// SPDX-License-Identifier: GPL-2.0 /* * Shared application/kernel submission and completion ring pairs, for * supporting fast/efficient IO. * * A note on the read/write ordering memory barriers that are matched between * the application and kernel side. * * After the application reads the CQ ring tail, it must use an * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses * before writing the tail (using smp_load_acquire to read the tail will * do). It also needs a smp_mb() before updating CQ head (ordering the * entry load(s) with the head store), pairing with an implicit barrier * through a control-dependency in io_get_cqring (smp_store_release to * store head will do). Failure to do so could lead to reading invalid * CQ entries. * * Likewise, the application must use an appropriate smp_wmb() before * writing the SQ tail (ordering SQ entry stores with the tail store), * which pairs with smp_load_acquire in io_get_sqring (smp_store_release * to store the tail will do). And it needs a barrier ordering the SQ * head load before writing new SQ entries (smp_load_acquire to read * head will do). * * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after* * updating the SQ tail; a full memory barrier smp_mb() is needed * between. * * Also see the examples in the liburing library: * * git://git.kernel.dk/liburing * * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens * from data shared between the kernel and application. This is done both * for ordering purposes, but also to ensure that once a value is loaded from * data that the application could potentially modify, it remains stable. * * Copyright (C) 2018-2019 Jens Axboe * Copyright (c) 2018-2019 Christoph Hellwig */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define CREATE_TRACE_POINTS #include #include #include "internal.h" #include "io-wq.h" #define IORING_MAX_ENTRIES 32768 #define IORING_MAX_CQ_ENTRIES (2 * IORING_MAX_ENTRIES) /* * Shift of 9 is 512 entries, or exactly one page on 64-bit archs */ #define IORING_FILE_TABLE_SHIFT 9 #define IORING_MAX_FILES_TABLE (1U << IORING_FILE_TABLE_SHIFT) #define IORING_FILE_TABLE_MASK (IORING_MAX_FILES_TABLE - 1) #define IORING_MAX_FIXED_FILES (64 * IORING_MAX_FILES_TABLE) struct io_uring { u32 head ____cacheline_aligned_in_smp; u32 tail ____cacheline_aligned_in_smp; }; /* * This data is shared with the application through the mmap at offsets * IORING_OFF_SQ_RING and IORING_OFF_CQ_RING. * * The offsets to the member fields are published through struct * io_sqring_offsets when calling io_uring_setup. */ struct io_rings { /* * Head and tail offsets into the ring; the offsets need to be * masked to get valid indices. * * The kernel controls head of the sq ring and the tail of the cq ring, * and the application controls tail of the sq ring and the head of the * cq ring. */ struct io_uring sq, cq; /* * Bitmasks to apply to head and tail offsets (constant, equals * ring_entries - 1) */ u32 sq_ring_mask, cq_ring_mask; /* Ring sizes (constant, power of 2) */ u32 sq_ring_entries, cq_ring_entries; /* * Number of invalid entries dropped by the kernel due to * invalid index stored in array * * Written by the kernel, shouldn't be modified by the * application (i.e. get number of "new events" by comparing to * cached value). * * After a new SQ head value was read by the application this * counter includes all submissions that were dropped reaching * the new SQ head (and possibly more). */ u32 sq_dropped; /* * Runtime flags * * Written by the kernel, shouldn't be modified by the * application. * * The application needs a full memory barrier before checking * for IORING_SQ_NEED_WAKEUP after updating the sq tail. */ u32 sq_flags; /* * Number of completion events lost because the queue was full; * this should be avoided by the application by making sure * there are not more requests pending than there is space in * the completion queue. * * Written by the kernel, shouldn't be modified by the * application (i.e. get number of "new events" by comparing to * cached value). * * As completion events come in out of order this counter is not * ordered with any other data. */ u32 cq_overflow; /* * Ring buffer of completion events. * * The kernel writes completion events fresh every time they are * produced, so the application is allowed to modify pending * entries. */ struct io_uring_cqe cqes[] ____cacheline_aligned_in_smp; }; struct io_mapped_ubuf { u64 ubuf; size_t len; struct bio_vec *bvec; unsigned int nr_bvecs; }; struct fixed_file_table { struct file **files; }; enum { FFD_F_ATOMIC, }; struct fixed_file_data { struct fixed_file_table *table; struct io_ring_ctx *ctx; struct percpu_ref refs; struct llist_head put_llist; unsigned long state; struct work_struct ref_work; struct completion done; }; struct io_ring_ctx { struct { struct percpu_ref refs; } ____cacheline_aligned_in_smp; struct { unsigned int flags; bool compat; bool account_mem; bool cq_overflow_flushed; bool drain_next; /* * Ring buffer of indices into array of io_uring_sqe, which is * mmapped by the application using the IORING_OFF_SQES offset. * * This indirection could e.g. be used to assign fixed * io_uring_sqe entries to operations and only submit them to * the queue when needed. * * The kernel modifies neither the indices array nor the entries * array. */ u32 *sq_array; unsigned cached_sq_head; unsigned sq_entries; unsigned sq_mask; unsigned sq_thread_idle; unsigned cached_sq_dropped; atomic_t cached_cq_overflow; unsigned long sq_check_overflow; struct list_head defer_list; struct list_head timeout_list; struct list_head cq_overflow_list; wait_queue_head_t inflight_wait; struct io_uring_sqe *sq_sqes; } ____cacheline_aligned_in_smp; struct io_rings *rings; /* IO offload */ struct io_wq *io_wq; struct task_struct *sqo_thread; /* if using sq thread polling */ struct mm_struct *sqo_mm; wait_queue_head_t sqo_wait; /* * If used, fixed file set. Writers must ensure that ->refs is dead, * readers must ensure that ->refs is alive as long as the file* is * used. Only updated through io_uring_register(2). */ struct fixed_file_data *file_data; unsigned nr_user_files; /* if used, fixed mapped user buffers */ unsigned nr_user_bufs; struct io_mapped_ubuf *user_bufs; struct user_struct *user; const struct cred *creds; /* 0 is for ctx quiesce/reinit/free, 1 is for sqo_thread started */ struct completion *completions; /* if all else fails... */ struct io_kiocb *fallback_req; #if defined(CONFIG_UNIX) struct socket *ring_sock; #endif struct { unsigned cached_cq_tail; unsigned cq_entries; unsigned cq_mask; atomic_t cq_timeouts; unsigned long cq_check_overflow; struct wait_queue_head cq_wait; struct fasync_struct *cq_fasync; struct eventfd_ctx *cq_ev_fd; } ____cacheline_aligned_in_smp; struct { struct mutex uring_lock; wait_queue_head_t wait; } ____cacheline_aligned_in_smp; struct { spinlock_t completion_lock; struct llist_head poll_llist; /* * ->poll_list is protected by the ctx->uring_lock for * io_uring instances that don't use IORING_SETUP_SQPOLL. * For SQPOLL, only the single threaded io_sq_thread() will * manipulate the list, hence no extra locking is needed there. */ struct list_head poll_list; struct hlist_head *cancel_hash; unsigned cancel_hash_bits; bool poll_multi_file; spinlock_t inflight_lock; struct list_head inflight_list; } ____cacheline_aligned_in_smp; }; /* * First field must be the file pointer in all the * iocb unions! See also 'struct kiocb' in */ struct io_poll_iocb { struct file *file; union { struct wait_queue_head *head; u64 addr; }; __poll_t events; bool done; bool canceled; struct wait_queue_entry wait; }; struct io_close { struct file *file; struct file *put_file; int fd; }; struct io_timeout_data { struct io_kiocb *req; struct hrtimer timer; struct timespec64 ts; enum hrtimer_mode mode; u32 seq_offset; }; struct io_accept { struct file *file; struct sockaddr __user *addr; int __user *addr_len; int flags; }; struct io_sync { struct file *file; loff_t len; loff_t off; int flags; int mode; }; struct io_cancel { struct file *file; u64 addr; }; struct io_timeout { struct file *file; u64 addr; int flags; unsigned count; }; struct io_rw { /* NOTE: kiocb has the file as the first member, so don't do it here */ struct kiocb kiocb; u64 addr; u64 len; }; struct io_connect { struct file *file; struct sockaddr __user *addr; int addr_len; }; struct io_sr_msg { struct file *file; union { struct user_msghdr __user *msg; void __user *buf; }; int msg_flags; size_t len; }; struct io_open { struct file *file; int dfd; union { umode_t mode; unsigned mask; }; const char __user *fname; struct filename *filename; struct statx __user *buffer; int flags; }; struct io_files_update { struct file *file; u64 arg; u32 nr_args; u32 offset; }; struct io_fadvise { struct file *file; u64 offset; u32 len; u32 advice; }; struct io_madvise { struct file *file; u64 addr; u32 len; u32 advice; }; struct io_async_connect { struct sockaddr_storage address; }; struct io_async_msghdr { struct iovec fast_iov[UIO_FASTIOV]; struct iovec *iov; struct sockaddr __user *uaddr; struct msghdr msg; }; struct io_async_rw { struct iovec fast_iov[UIO_FASTIOV]; struct iovec *iov; ssize_t nr_segs; ssize_t size; }; struct io_async_open { struct filename *filename; }; struct io_async_ctx { union { struct io_async_rw rw; struct io_async_msghdr msg; struct io_async_connect connect; struct io_timeout_data timeout; struct io_async_open open; }; }; /* * NOTE! Each of the iocb union members has the file pointer * as the first entry in their struct definition. So you can * access the file pointer through any of the sub-structs, * or directly as just 'ki_filp' in this struct. */ struct io_kiocb { union { struct file *file; struct io_rw rw; struct io_poll_iocb poll; struct io_accept accept; struct io_sync sync; struct io_cancel cancel; struct io_timeout timeout; struct io_connect connect; struct io_sr_msg sr_msg; struct io_open open; struct io_close close; struct io_files_update files_update; struct io_fadvise fadvise; struct io_madvise madvise; }; struct io_async_ctx *io; union { /* * ring_file is only used in the submission path, and * llist_node is only used for poll deferred completions */ struct file *ring_file; struct llist_node llist_node; }; int ring_fd; bool has_user; bool in_async; bool needs_fixed_file; u8 opcode; struct io_ring_ctx *ctx; union { struct list_head list; struct hlist_node hash_node; }; struct list_head link_list; unsigned int flags; refcount_t refs; #define REQ_F_NOWAIT 1 /* must not punt to workers */ #define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */ #define REQ_F_FIXED_FILE 4 /* ctx owns file */ #define REQ_F_LINK_NEXT 8 /* already grabbed next link */ #define REQ_F_IO_DRAIN 16 /* drain existing IO first */ #define REQ_F_IO_DRAINED 32 /* drain done */ #define REQ_F_LINK 64 /* linked sqes */ #define REQ_F_LINK_TIMEOUT 128 /* has linked timeout */ #define REQ_F_FAIL_LINK 256 /* fail rest of links */ #define REQ_F_DRAIN_LINK 512 /* link should be fully drained */ #define REQ_F_TIMEOUT 1024 /* timeout request */ #define REQ_F_ISREG 2048 /* regular file */ #define REQ_F_MUST_PUNT 4096 /* must be punted even for NONBLOCK */ #define REQ_F_TIMEOUT_NOSEQ 8192 /* no timeout sequence */ #define REQ_F_INFLIGHT 16384 /* on inflight list */ #define REQ_F_COMP_LOCKED 32768 /* completion under lock */ #define REQ_F_HARDLINK 65536 /* doesn't sever on completion < 0 */ #define REQ_F_FORCE_ASYNC 131072 /* IOSQE_ASYNC */ #define REQ_F_CUR_POS 262144 /* read/write uses file position */ u64 user_data; u32 result; u32 sequence; struct list_head inflight_entry; struct io_wq_work work; }; #define IO_PLUG_THRESHOLD 2 #define IO_IOPOLL_BATCH 8 struct io_submit_state { struct blk_plug plug; /* * io_kiocb alloc cache */ void *reqs[IO_IOPOLL_BATCH]; unsigned int free_reqs; unsigned int cur_req; /* * File reference cache */ struct file *file; unsigned int fd; unsigned int has_refs; unsigned int used_refs; unsigned int ios_left; }; struct io_op_def { /* needs req->io allocated for deferral/async */ unsigned async_ctx : 1; /* needs current->mm setup, does mm access */ unsigned needs_mm : 1; /* needs req->file assigned */ unsigned needs_file : 1; /* needs req->file assigned IFF fd is >= 0 */ unsigned fd_non_neg : 1; /* hash wq insertion if file is a regular file */ unsigned hash_reg_file : 1; /* unbound wq insertion if file is a non-regular file */ unsigned unbound_nonreg_file : 1; }; static const struct io_op_def io_op_defs[] = { { /* IORING_OP_NOP */ }, { /* IORING_OP_READV */ .async_ctx = 1, .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_WRITEV */ .async_ctx = 1, .needs_mm = 1, .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_FSYNC */ .needs_file = 1, }, { /* IORING_OP_READ_FIXED */ .needs_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_WRITE_FIXED */ .needs_file = 1, .hash_reg_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_POLL_ADD */ .needs_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_POLL_REMOVE */ }, { /* IORING_OP_SYNC_FILE_RANGE */ .needs_file = 1, }, { /* IORING_OP_SENDMSG */ .async_ctx = 1, .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_RECVMSG */ .async_ctx = 1, .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_TIMEOUT */ .async_ctx = 1, .needs_mm = 1, }, { /* IORING_OP_TIMEOUT_REMOVE */ }, { /* IORING_OP_ACCEPT */ .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_ASYNC_CANCEL */ }, { /* IORING_OP_LINK_TIMEOUT */ .async_ctx = 1, .needs_mm = 1, }, { /* IORING_OP_CONNECT */ .async_ctx = 1, .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_FALLOCATE */ .needs_file = 1, }, { /* IORING_OP_OPENAT */ .needs_file = 1, .fd_non_neg = 1, }, { /* IORING_OP_CLOSE */ .needs_file = 1, }, { /* IORING_OP_FILES_UPDATE */ .needs_mm = 1, }, { /* IORING_OP_STATX */ .needs_mm = 1, .needs_file = 1, .fd_non_neg = 1, }, { /* IORING_OP_READ */ .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_WRITE */ .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_FADVISE */ .needs_file = 1, }, { /* IORING_OP_MADVISE */ .needs_mm = 1, }, { /* IORING_OP_SEND */ .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, }, { /* IORING_OP_RECV */ .needs_mm = 1, .needs_file = 1, .unbound_nonreg_file = 1, }, }; static void io_wq_submit_work(struct io_wq_work **workptr); static void io_cqring_fill_event(struct io_kiocb *req, long res); static void io_put_req(struct io_kiocb *req); static void __io_double_put_req(struct io_kiocb *req); static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req); static void io_queue_linked_timeout(struct io_kiocb *req); static int __io_sqe_files_update(struct io_ring_ctx *ctx, struct io_uring_files_update *ip, unsigned nr_args); static struct kmem_cache *req_cachep; static const struct file_operations io_uring_fops; struct sock *io_uring_get_socket(struct file *file) { #if defined(CONFIG_UNIX) if (file->f_op == &io_uring_fops) { struct io_ring_ctx *ctx = file->private_data; return ctx->ring_sock->sk; } #endif return NULL; } EXPORT_SYMBOL(io_uring_get_socket); static void io_ring_ctx_ref_free(struct percpu_ref *ref) { struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs); complete(&ctx->completions[0]); } static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p) { struct io_ring_ctx *ctx; int hash_bits; ctx = kzalloc(sizeof(*ctx), GFP_KERNEL); if (!ctx) return NULL; ctx->fallback_req = kmem_cache_alloc(req_cachep, GFP_KERNEL); if (!ctx->fallback_req) goto err; ctx->completions = kmalloc(2 * sizeof(struct completion), GFP_KERNEL); if (!ctx->completions) goto err; /* * Use 5 bits less than the max cq entries, that should give us around * 32 entries per hash list if totally full and uniformly spread. */ hash_bits = ilog2(p->cq_entries); hash_bits -= 5; if (hash_bits <= 0) hash_bits = 1; ctx->cancel_hash_bits = hash_bits; ctx->cancel_hash = kmalloc((1U << hash_bits) * sizeof(struct hlist_head), GFP_KERNEL); if (!ctx->cancel_hash) goto err; __hash_init(ctx->cancel_hash, 1U << hash_bits); if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free, PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) goto err; ctx->flags = p->flags; init_waitqueue_head(&ctx->cq_wait); INIT_LIST_HEAD(&ctx->cq_overflow_list); init_completion(&ctx->completions[0]); init_completion(&ctx->completions[1]); mutex_init(&ctx->uring_lock); init_waitqueue_head(&ctx->wait); spin_lock_init(&ctx->completion_lock); init_llist_head(&ctx->poll_llist); INIT_LIST_HEAD(&ctx->poll_list); INIT_LIST_HEAD(&ctx->defer_list); INIT_LIST_HEAD(&ctx->timeout_list); init_waitqueue_head(&ctx->inflight_wait); spin_lock_init(&ctx->inflight_lock); INIT_LIST_HEAD(&ctx->inflight_list); return ctx; err: if (ctx->fallback_req) kmem_cache_free(req_cachep, ctx->fallback_req); kfree(ctx->completions); kfree(ctx->cancel_hash); kfree(ctx); return NULL; } static inline bool __req_need_defer(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; return req->sequence != ctx->cached_cq_tail + ctx->cached_sq_dropped + atomic_read(&ctx->cached_cq_overflow); } static inline bool req_need_defer(struct io_kiocb *req) { if ((req->flags & (REQ_F_IO_DRAIN|REQ_F_IO_DRAINED)) == REQ_F_IO_DRAIN) return __req_need_defer(req); return false; } static struct io_kiocb *io_get_deferred_req(struct io_ring_ctx *ctx) { struct io_kiocb *req; req = list_first_entry_or_null(&ctx->defer_list, struct io_kiocb, list); if (req && !req_need_defer(req)) { list_del_init(&req->list); return req; } return NULL; } static struct io_kiocb *io_get_timeout_req(struct io_ring_ctx *ctx) { struct io_kiocb *req; req = list_first_entry_or_null(&ctx->timeout_list, struct io_kiocb, list); if (req) { if (req->flags & REQ_F_TIMEOUT_NOSEQ) return NULL; if (!__req_need_defer(req)) { list_del_init(&req->list); return req; } } return NULL; } static void __io_commit_cqring(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; if (ctx->cached_cq_tail != READ_ONCE(rings->cq.tail)) { /* order cqe stores with ring update */ smp_store_release(&rings->cq.tail, ctx->cached_cq_tail); if (wq_has_sleeper(&ctx->cq_wait)) { wake_up_interruptible(&ctx->cq_wait); kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN); } } } static inline bool io_prep_async_work(struct io_kiocb *req, struct io_kiocb **link) { const struct io_op_def *def = &io_op_defs[req->opcode]; bool do_hashed = false; if (req->flags & REQ_F_ISREG) { if (def->hash_reg_file) do_hashed = true; } else { if (def->unbound_nonreg_file) req->work.flags |= IO_WQ_WORK_UNBOUND; } if (def->needs_mm) req->work.flags |= IO_WQ_WORK_NEEDS_USER; *link = io_prep_linked_timeout(req); return do_hashed; } static inline void io_queue_async_work(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *link; bool do_hashed; do_hashed = io_prep_async_work(req, &link); trace_io_uring_queue_async_work(ctx, do_hashed, req, &req->work, req->flags); if (!do_hashed) { io_wq_enqueue(ctx->io_wq, &req->work); } else { io_wq_enqueue_hashed(ctx->io_wq, &req->work, file_inode(req->file)); } if (link) io_queue_linked_timeout(link); } static void io_kill_timeout(struct io_kiocb *req) { int ret; ret = hrtimer_try_to_cancel(&req->io->timeout.timer); if (ret != -1) { atomic_inc(&req->ctx->cq_timeouts); list_del_init(&req->list); io_cqring_fill_event(req, 0); io_put_req(req); } } static void io_kill_timeouts(struct io_ring_ctx *ctx) { struct io_kiocb *req, *tmp; spin_lock_irq(&ctx->completion_lock); list_for_each_entry_safe(req, tmp, &ctx->timeout_list, list) io_kill_timeout(req); spin_unlock_irq(&ctx->completion_lock); } static void io_commit_cqring(struct io_ring_ctx *ctx) { struct io_kiocb *req; while ((req = io_get_timeout_req(ctx)) != NULL) io_kill_timeout(req); __io_commit_cqring(ctx); while ((req = io_get_deferred_req(ctx)) != NULL) { req->flags |= REQ_F_IO_DRAINED; io_queue_async_work(req); } } static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; unsigned tail; tail = ctx->cached_cq_tail; /* * writes to the cq entry need to come after reading head; the * control dependency is enough as we're using WRITE_ONCE to * fill the cq entry */ if (tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries) return NULL; ctx->cached_cq_tail++; return &rings->cqes[tail & ctx->cq_mask]; } static void io_cqring_ev_posted(struct io_ring_ctx *ctx) { if (waitqueue_active(&ctx->wait)) wake_up(&ctx->wait); if (waitqueue_active(&ctx->sqo_wait)) wake_up(&ctx->sqo_wait); if (ctx->cq_ev_fd) eventfd_signal(ctx->cq_ev_fd, 1); } /* Returns true if there are no backlogged entries after the flush */ static bool io_cqring_overflow_flush(struct io_ring_ctx *ctx, bool force) { struct io_rings *rings = ctx->rings; struct io_uring_cqe *cqe; struct io_kiocb *req; unsigned long flags; LIST_HEAD(list); if (!force) { if (list_empty_careful(&ctx->cq_overflow_list)) return true; if ((ctx->cached_cq_tail - READ_ONCE(rings->cq.head) == rings->cq_ring_entries)) return false; } spin_lock_irqsave(&ctx->completion_lock, flags); /* if force is set, the ring is going away. always drop after that */ if (force) ctx->cq_overflow_flushed = true; cqe = NULL; while (!list_empty(&ctx->cq_overflow_list)) { cqe = io_get_cqring(ctx); if (!cqe && !force) break; req = list_first_entry(&ctx->cq_overflow_list, struct io_kiocb, list); list_move(&req->list, &list); if (cqe) { WRITE_ONCE(cqe->user_data, req->user_data); WRITE_ONCE(cqe->res, req->result); WRITE_ONCE(cqe->flags, 0); } else { WRITE_ONCE(ctx->rings->cq_overflow, atomic_inc_return(&ctx->cached_cq_overflow)); } } io_commit_cqring(ctx); if (cqe) { clear_bit(0, &ctx->sq_check_overflow); clear_bit(0, &ctx->cq_check_overflow); } spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); while (!list_empty(&list)) { req = list_first_entry(&list, struct io_kiocb, list); list_del(&req->list); io_put_req(req); } return cqe != NULL; } static void io_cqring_fill_event(struct io_kiocb *req, long res) { struct io_ring_ctx *ctx = req->ctx; struct io_uring_cqe *cqe; trace_io_uring_complete(ctx, req->user_data, res); /* * If we can't get a cq entry, userspace overflowed the * submission (by quite a lot). Increment the overflow count in * the ring. */ cqe = io_get_cqring(ctx); if (likely(cqe)) { WRITE_ONCE(cqe->user_data, req->user_data); WRITE_ONCE(cqe->res, res); WRITE_ONCE(cqe->flags, 0); } else if (ctx->cq_overflow_flushed) { WRITE_ONCE(ctx->rings->cq_overflow, atomic_inc_return(&ctx->cached_cq_overflow)); } else { if (list_empty(&ctx->cq_overflow_list)) { set_bit(0, &ctx->sq_check_overflow); set_bit(0, &ctx->cq_check_overflow); } refcount_inc(&req->refs); req->result = res; list_add_tail(&req->list, &ctx->cq_overflow_list); } } static void io_cqring_add_event(struct io_kiocb *req, long res) { struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); io_cqring_fill_event(req, res); io_commit_cqring(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); } static inline bool io_is_fallback_req(struct io_kiocb *req) { return req == (struct io_kiocb *) ((unsigned long) req->ctx->fallback_req & ~1UL); } static struct io_kiocb *io_get_fallback_req(struct io_ring_ctx *ctx) { struct io_kiocb *req; req = ctx->fallback_req; if (!test_and_set_bit_lock(0, (unsigned long *) ctx->fallback_req)) return req; return NULL; } static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx, struct io_submit_state *state) { gfp_t gfp = GFP_KERNEL | __GFP_NOWARN; struct io_kiocb *req; if (!state) { req = kmem_cache_alloc(req_cachep, gfp); if (unlikely(!req)) goto fallback; } else if (!state->free_reqs) { size_t sz; int ret; sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs)); ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz, state->reqs); /* * Bulk alloc is all-or-nothing. If we fail to get a batch, * retry single alloc to be on the safe side. */ if (unlikely(ret <= 0)) { state->reqs[0] = kmem_cache_alloc(req_cachep, gfp); if (!state->reqs[0]) goto fallback; ret = 1; } state->free_reqs = ret - 1; state->cur_req = 1; req = state->reqs[0]; } else { req = state->reqs[state->cur_req]; state->free_reqs--; state->cur_req++; } got_it: req->io = NULL; req->ring_file = NULL; req->file = NULL; req->ctx = ctx; req->flags = 0; /* one is dropped after submission, the other at completion */ refcount_set(&req->refs, 2); req->result = 0; INIT_IO_WORK(&req->work, io_wq_submit_work); return req; fallback: req = io_get_fallback_req(ctx); if (req) goto got_it; percpu_ref_put(&ctx->refs); return NULL; } static void __io_req_do_free(struct io_kiocb *req) { if (likely(!io_is_fallback_req(req))) kmem_cache_free(req_cachep, req); else clear_bit_unlock(0, (unsigned long *) req->ctx->fallback_req); } static void __io_req_aux_free(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; kfree(req->io); if (req->file) { if (req->flags & REQ_F_FIXED_FILE) percpu_ref_put(&ctx->file_data->refs); else fput(req->file); } } static void __io_free_req(struct io_kiocb *req) { __io_req_aux_free(req); if (req->flags & REQ_F_INFLIGHT) { struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->inflight_lock, flags); list_del(&req->inflight_entry); if (waitqueue_active(&ctx->inflight_wait)) wake_up(&ctx->inflight_wait); spin_unlock_irqrestore(&ctx->inflight_lock, flags); } percpu_ref_put(&req->ctx->refs); __io_req_do_free(req); } struct req_batch { void *reqs[IO_IOPOLL_BATCH]; int to_free; int need_iter; }; static void io_free_req_many(struct io_ring_ctx *ctx, struct req_batch *rb) { if (!rb->to_free) return; if (rb->need_iter) { int i, inflight = 0; unsigned long flags; for (i = 0; i < rb->to_free; i++) { struct io_kiocb *req = rb->reqs[i]; if (req->flags & REQ_F_FIXED_FILE) req->file = NULL; if (req->flags & REQ_F_INFLIGHT) inflight++; else rb->reqs[i] = NULL; __io_req_aux_free(req); } if (!inflight) goto do_free; spin_lock_irqsave(&ctx->inflight_lock, flags); for (i = 0; i < rb->to_free; i++) { struct io_kiocb *req = rb->reqs[i]; if (req) { list_del(&req->inflight_entry); if (!--inflight) break; } } spin_unlock_irqrestore(&ctx->inflight_lock, flags); if (waitqueue_active(&ctx->inflight_wait)) wake_up(&ctx->inflight_wait); } do_free: kmem_cache_free_bulk(req_cachep, rb->to_free, rb->reqs); percpu_ref_put_many(&ctx->refs, rb->to_free); percpu_ref_put_many(&ctx->file_data->refs, rb->to_free); rb->to_free = rb->need_iter = 0; } static bool io_link_cancel_timeout(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; int ret; ret = hrtimer_try_to_cancel(&req->io->timeout.timer); if (ret != -1) { io_cqring_fill_event(req, -ECANCELED); io_commit_cqring(ctx); req->flags &= ~REQ_F_LINK; io_put_req(req); return true; } return false; } static void io_req_link_next(struct io_kiocb *req, struct io_kiocb **nxtptr) { struct io_ring_ctx *ctx = req->ctx; bool wake_ev = false; /* Already got next link */ if (req->flags & REQ_F_LINK_NEXT) return; /* * The list should never be empty when we are called here. But could * potentially happen if the chain is messed up, check to be on the * safe side. */ while (!list_empty(&req->link_list)) { struct io_kiocb *nxt = list_first_entry(&req->link_list, struct io_kiocb, link_list); if (unlikely((req->flags & REQ_F_LINK_TIMEOUT) && (nxt->flags & REQ_F_TIMEOUT))) { list_del_init(&nxt->link_list); wake_ev |= io_link_cancel_timeout(nxt); req->flags &= ~REQ_F_LINK_TIMEOUT; continue; } list_del_init(&req->link_list); if (!list_empty(&nxt->link_list)) nxt->flags |= REQ_F_LINK; *nxtptr = nxt; break; } req->flags |= REQ_F_LINK_NEXT; if (wake_ev) io_cqring_ev_posted(ctx); } /* * Called if REQ_F_LINK is set, and we fail the head request */ static void io_fail_links(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); while (!list_empty(&req->link_list)) { struct io_kiocb *link = list_first_entry(&req->link_list, struct io_kiocb, link_list); list_del_init(&link->link_list); trace_io_uring_fail_link(req, link); if ((req->flags & REQ_F_LINK_TIMEOUT) && link->opcode == IORING_OP_LINK_TIMEOUT) { io_link_cancel_timeout(link); } else { io_cqring_fill_event(link, -ECANCELED); __io_double_put_req(link); } req->flags &= ~REQ_F_LINK_TIMEOUT; } io_commit_cqring(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); } static void io_req_find_next(struct io_kiocb *req, struct io_kiocb **nxt) { if (likely(!(req->flags & REQ_F_LINK))) return; /* * If LINK is set, we have dependent requests in this chain. If we * didn't fail this request, queue the first one up, moving any other * dependencies to the next request. In case of failure, fail the rest * of the chain. */ if (req->flags & REQ_F_FAIL_LINK) { io_fail_links(req); } else if ((req->flags & (REQ_F_LINK_TIMEOUT | REQ_F_COMP_LOCKED)) == REQ_F_LINK_TIMEOUT) { struct io_ring_ctx *ctx = req->ctx; unsigned long flags; /* * If this is a timeout link, we could be racing with the * timeout timer. Grab the completion lock for this case to * protect against that. */ spin_lock_irqsave(&ctx->completion_lock, flags); io_req_link_next(req, nxt); spin_unlock_irqrestore(&ctx->completion_lock, flags); } else { io_req_link_next(req, nxt); } } static void io_free_req(struct io_kiocb *req) { struct io_kiocb *nxt = NULL; io_req_find_next(req, &nxt); __io_free_req(req); if (nxt) io_queue_async_work(nxt); } /* * Drop reference to request, return next in chain (if there is one) if this * was the last reference to this request. */ __attribute__((nonnull)) static void io_put_req_find_next(struct io_kiocb *req, struct io_kiocb **nxtptr) { io_req_find_next(req, nxtptr); if (refcount_dec_and_test(&req->refs)) __io_free_req(req); } static void io_put_req(struct io_kiocb *req) { if (refcount_dec_and_test(&req->refs)) io_free_req(req); } /* * Must only be used if we don't need to care about links, usually from * within the completion handling itself. */ static void __io_double_put_req(struct io_kiocb *req) { /* drop both submit and complete references */ if (refcount_sub_and_test(2, &req->refs)) __io_free_req(req); } static void io_double_put_req(struct io_kiocb *req) { /* drop both submit and complete references */ if (refcount_sub_and_test(2, &req->refs)) io_free_req(req); } static unsigned io_cqring_events(struct io_ring_ctx *ctx, bool noflush) { struct io_rings *rings = ctx->rings; if (test_bit(0, &ctx->cq_check_overflow)) { /* * noflush == true is from the waitqueue handler, just ensure * we wake up the task, and the next invocation will flush the * entries. We cannot safely to it from here. */ if (noflush && !list_empty(&ctx->cq_overflow_list)) return -1U; io_cqring_overflow_flush(ctx, false); } /* See comment at the top of this file */ smp_rmb(); return ctx->cached_cq_tail - READ_ONCE(rings->cq.head); } static inline unsigned int io_sqring_entries(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; /* make sure SQ entry isn't read before tail */ return smp_load_acquire(&rings->sq.tail) - ctx->cached_sq_head; } static inline bool io_req_multi_free(struct req_batch *rb, struct io_kiocb *req) { if ((req->flags & REQ_F_LINK) || io_is_fallback_req(req)) return false; if (!(req->flags & REQ_F_FIXED_FILE) || req->io) rb->need_iter++; rb->reqs[rb->to_free++] = req; if (unlikely(rb->to_free == ARRAY_SIZE(rb->reqs))) io_free_req_many(req->ctx, rb); return true; } /* * Find and free completed poll iocbs */ static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events, struct list_head *done) { struct req_batch rb; struct io_kiocb *req; rb.to_free = rb.need_iter = 0; while (!list_empty(done)) { req = list_first_entry(done, struct io_kiocb, list); list_del(&req->list); io_cqring_fill_event(req, req->result); (*nr_events)++; if (refcount_dec_and_test(&req->refs) && !io_req_multi_free(&rb, req)) io_free_req(req); } io_commit_cqring(ctx); io_free_req_many(ctx, &rb); } static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events, long min) { struct io_kiocb *req, *tmp; LIST_HEAD(done); bool spin; int ret; /* * Only spin for completions if we don't have multiple devices hanging * off our complete list, and we're under the requested amount. */ spin = !ctx->poll_multi_file && *nr_events < min; ret = 0; list_for_each_entry_safe(req, tmp, &ctx->poll_list, list) { struct kiocb *kiocb = &req->rw.kiocb; /* * Move completed entries to our local list. If we find a * request that requires polling, break out and complete * the done list first, if we have entries there. */ if (req->flags & REQ_F_IOPOLL_COMPLETED) { list_move_tail(&req->list, &done); continue; } if (!list_empty(&done)) break; ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin); if (ret < 0) break; if (ret && spin) spin = false; ret = 0; } if (!list_empty(&done)) io_iopoll_complete(ctx, nr_events, &done); return ret; } /* * Poll for a minimum of 'min' events. Note that if min == 0 we consider that a * non-spinning poll check - we'll still enter the driver poll loop, but only * as a non-spinning completion check. */ static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events, long min) { while (!list_empty(&ctx->poll_list) && !need_resched()) { int ret; ret = io_do_iopoll(ctx, nr_events, min); if (ret < 0) return ret; if (!min || *nr_events >= min) return 0; } return 1; } /* * We can't just wait for polled events to come to us, we have to actively * find and complete them. */ static void io_iopoll_reap_events(struct io_ring_ctx *ctx) { if (!(ctx->flags & IORING_SETUP_IOPOLL)) return; mutex_lock(&ctx->uring_lock); while (!list_empty(&ctx->poll_list)) { unsigned int nr_events = 0; io_iopoll_getevents(ctx, &nr_events, 1); /* * Ensure we allow local-to-the-cpu processing to take place, * in this case we need to ensure that we reap all events. */ cond_resched(); } mutex_unlock(&ctx->uring_lock); } static int __io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, long min) { int iters = 0, ret = 0; do { int tmin = 0; /* * Don't enter poll loop if we already have events pending. * If we do, we can potentially be spinning for commands that * already triggered a CQE (eg in error). */ if (io_cqring_events(ctx, false)) break; /* * If a submit got punted to a workqueue, we can have the * application entering polling for a command before it gets * issued. That app will hold the uring_lock for the duration * of the poll right here, so we need to take a breather every * now and then to ensure that the issue has a chance to add * the poll to the issued list. Otherwise we can spin here * forever, while the workqueue is stuck trying to acquire the * very same mutex. */ if (!(++iters & 7)) { mutex_unlock(&ctx->uring_lock); mutex_lock(&ctx->uring_lock); } if (*nr_events < min) tmin = min - *nr_events; ret = io_iopoll_getevents(ctx, nr_events, tmin); if (ret <= 0) break; ret = 0; } while (min && !*nr_events && !need_resched()); return ret; } static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events, long min) { int ret; /* * We disallow the app entering submit/complete with polling, but we * still need to lock the ring to prevent racing with polled issue * that got punted to a workqueue. */ mutex_lock(&ctx->uring_lock); ret = __io_iopoll_check(ctx, nr_events, min); mutex_unlock(&ctx->uring_lock); return ret; } static void kiocb_end_write(struct io_kiocb *req) { /* * Tell lockdep we inherited freeze protection from submission * thread. */ if (req->flags & REQ_F_ISREG) { struct inode *inode = file_inode(req->file); __sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE); } file_end_write(req->file); } static inline void req_set_fail_links(struct io_kiocb *req) { if ((req->flags & (REQ_F_LINK | REQ_F_HARDLINK)) == REQ_F_LINK) req->flags |= REQ_F_FAIL_LINK; } static void io_complete_rw_common(struct kiocb *kiocb, long res) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); if (kiocb->ki_flags & IOCB_WRITE) kiocb_end_write(req); if (res != req->result) req_set_fail_links(req); io_cqring_add_event(req, res); } static void io_complete_rw(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); io_complete_rw_common(kiocb, res); io_put_req(req); } static struct io_kiocb *__io_complete_rw(struct kiocb *kiocb, long res) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); struct io_kiocb *nxt = NULL; io_complete_rw_common(kiocb, res); io_put_req_find_next(req, &nxt); return nxt; } static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); if (kiocb->ki_flags & IOCB_WRITE) kiocb_end_write(req); if (res != req->result) req_set_fail_links(req); req->result = res; if (res != -EAGAIN) req->flags |= REQ_F_IOPOLL_COMPLETED; } /* * After the iocb has been issued, it's safe to be found on the poll list. * Adding the kiocb to the list AFTER submission ensures that we don't * find it from a io_iopoll_getevents() thread before the issuer is done * accessing the kiocb cookie. */ static void io_iopoll_req_issued(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; /* * Track whether we have multiple files in our lists. This will impact * how we do polling eventually, not spinning if we're on potentially * different devices. */ if (list_empty(&ctx->poll_list)) { ctx->poll_multi_file = false; } else if (!ctx->poll_multi_file) { struct io_kiocb *list_req; list_req = list_first_entry(&ctx->poll_list, struct io_kiocb, list); if (list_req->file != req->file) ctx->poll_multi_file = true; } /* * For fast devices, IO may have already completed. If it has, add * it to the front so we find it first. */ if (req->flags & REQ_F_IOPOLL_COMPLETED) list_add(&req->list, &ctx->poll_list); else list_add_tail(&req->list, &ctx->poll_list); } static void io_file_put(struct io_submit_state *state) { if (state->file) { int diff = state->has_refs - state->used_refs; if (diff) fput_many(state->file, diff); state->file = NULL; } } /* * Get as many references to a file as we have IOs left in this submission, * assuming most submissions are for one file, or at least that each file * has more than one submission. */ static struct file *io_file_get(struct io_submit_state *state, int fd) { if (!state) return fget(fd); if (state->file) { if (state->fd == fd) { state->used_refs++; state->ios_left--; return state->file; } io_file_put(state); } state->file = fget_many(fd, state->ios_left); if (!state->file) return NULL; state->fd = fd; state->has_refs = state->ios_left; state->used_refs = 1; state->ios_left--; return state->file; } /* * If we tracked the file through the SCM inflight mechanism, we could support * any file. For now, just ensure that anything potentially problematic is done * inline. */ static bool io_file_supports_async(struct file *file) { umode_t mode = file_inode(file)->i_mode; if (S_ISBLK(mode) || S_ISCHR(mode) || S_ISSOCK(mode)) return true; if (S_ISREG(mode) && file->f_op != &io_uring_fops) return true; return false; } static int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool force_nonblock) { struct io_ring_ctx *ctx = req->ctx; struct kiocb *kiocb = &req->rw.kiocb; unsigned ioprio; int ret; if (!req->file) return -EBADF; if (S_ISREG(file_inode(req->file)->i_mode)) req->flags |= REQ_F_ISREG; kiocb->ki_pos = READ_ONCE(sqe->off); if (kiocb->ki_pos == -1 && !(req->file->f_mode & FMODE_STREAM)) { req->flags |= REQ_F_CUR_POS; kiocb->ki_pos = req->file->f_pos; } kiocb->ki_flags = iocb_flags(kiocb->ki_filp); kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp)); ioprio = READ_ONCE(sqe->ioprio); if (ioprio) { ret = ioprio_check_cap(ioprio); if (ret) return ret; kiocb->ki_ioprio = ioprio; } else kiocb->ki_ioprio = get_current_ioprio(); ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags)); if (unlikely(ret)) return ret; /* don't allow async punt if RWF_NOWAIT was requested */ if ((kiocb->ki_flags & IOCB_NOWAIT) || (req->file->f_flags & O_NONBLOCK)) req->flags |= REQ_F_NOWAIT; if (force_nonblock) kiocb->ki_flags |= IOCB_NOWAIT; if (ctx->flags & IORING_SETUP_IOPOLL) { if (!(kiocb->ki_flags & IOCB_DIRECT) || !kiocb->ki_filp->f_op->iopoll) return -EOPNOTSUPP; kiocb->ki_flags |= IOCB_HIPRI; kiocb->ki_complete = io_complete_rw_iopoll; req->result = 0; } else { if (kiocb->ki_flags & IOCB_HIPRI) return -EINVAL; kiocb->ki_complete = io_complete_rw; } req->rw.addr = READ_ONCE(sqe->addr); req->rw.len = READ_ONCE(sqe->len); /* we own ->private, reuse it for the buffer index */ req->rw.kiocb.private = (void *) (unsigned long) READ_ONCE(sqe->buf_index); return 0; } static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) { switch (ret) { case -EIOCBQUEUED: break; case -ERESTARTSYS: case -ERESTARTNOINTR: case -ERESTARTNOHAND: case -ERESTART_RESTARTBLOCK: /* * We can't just restart the syscall, since previously * submitted sqes may already be in progress. Just fail this * IO with EINTR. */ ret = -EINTR; /* fall through */ default: kiocb->ki_complete(kiocb, ret, 0); } } static void kiocb_done(struct kiocb *kiocb, ssize_t ret, struct io_kiocb **nxt, bool in_async) { struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw.kiocb); if (req->flags & REQ_F_CUR_POS) req->file->f_pos = kiocb->ki_pos; if (in_async && ret >= 0 && kiocb->ki_complete == io_complete_rw) *nxt = __io_complete_rw(kiocb, ret); else io_rw_done(kiocb, ret); } static ssize_t io_import_fixed(struct io_kiocb *req, int rw, struct iov_iter *iter) { struct io_ring_ctx *ctx = req->ctx; size_t len = req->rw.len; struct io_mapped_ubuf *imu; unsigned index, buf_index; size_t offset; u64 buf_addr; /* attempt to use fixed buffers without having provided iovecs */ if (unlikely(!ctx->user_bufs)) return -EFAULT; buf_index = (unsigned long) req->rw.kiocb.private; if (unlikely(buf_index >= ctx->nr_user_bufs)) return -EFAULT; index = array_index_nospec(buf_index, ctx->nr_user_bufs); imu = &ctx->user_bufs[index]; buf_addr = req->rw.addr; /* overflow */ if (buf_addr + len < buf_addr) return -EFAULT; /* not inside the mapped region */ if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len) return -EFAULT; /* * May not be a start of buffer, set size appropriately * and advance us to the beginning. */ offset = buf_addr - imu->ubuf; iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len); if (offset) { /* * Don't use iov_iter_advance() here, as it's really slow for * using the latter parts of a big fixed buffer - it iterates * over each segment manually. We can cheat a bit here, because * we know that: * * 1) it's a BVEC iter, we set it up * 2) all bvecs are PAGE_SIZE in size, except potentially the * first and last bvec * * So just find our index, and adjust the iterator afterwards. * If the offset is within the first bvec (or the whole first * bvec, just use iov_iter_advance(). This makes it easier * since we can just skip the first segment, which may not * be PAGE_SIZE aligned. */ const struct bio_vec *bvec = imu->bvec; if (offset <= bvec->bv_len) { iov_iter_advance(iter, offset); } else { unsigned long seg_skip; /* skip first vec */ offset -= bvec->bv_len; seg_skip = 1 + (offset >> PAGE_SHIFT); iter->bvec = bvec + seg_skip; iter->nr_segs -= seg_skip; iter->count -= bvec->bv_len + offset; iter->iov_offset = offset & ~PAGE_MASK; } } return len; } static ssize_t io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec, struct iov_iter *iter) { void __user *buf = u64_to_user_ptr(req->rw.addr); size_t sqe_len = req->rw.len; u8 opcode; opcode = req->opcode; if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) { *iovec = NULL; return io_import_fixed(req, rw, iter); } /* buffer index only valid with fixed read/write */ if (req->rw.kiocb.private) return -EINVAL; if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE) { ssize_t ret; ret = import_single_range(rw, buf, sqe_len, *iovec, iter); *iovec = NULL; return ret; } if (req->io) { struct io_async_rw *iorw = &req->io->rw; *iovec = iorw->iov; iov_iter_init(iter, rw, *iovec, iorw->nr_segs, iorw->size); if (iorw->iov == iorw->fast_iov) *iovec = NULL; return iorw->size; } if (!req->has_user) return -EFAULT; #ifdef CONFIG_COMPAT if (req->ctx->compat) return compat_import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter); #endif return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter); } /* * For files that don't have ->read_iter() and ->write_iter(), handle them * by looping over ->read() or ->write() manually. */ static ssize_t loop_rw_iter(int rw, struct file *file, struct kiocb *kiocb, struct iov_iter *iter) { ssize_t ret = 0; /* * Don't support polled IO through this interface, and we can't * support non-blocking either. For the latter, this just causes * the kiocb to be handled from an async context. */ if (kiocb->ki_flags & IOCB_HIPRI) return -EOPNOTSUPP; if (kiocb->ki_flags & IOCB_NOWAIT) return -EAGAIN; while (iov_iter_count(iter)) { struct iovec iovec; ssize_t nr; if (!iov_iter_is_bvec(iter)) { iovec = iov_iter_iovec(iter); } else { /* fixed buffers import bvec */ iovec.iov_base = kmap(iter->bvec->bv_page) + iter->iov_offset; iovec.iov_len = min(iter->count, iter->bvec->bv_len - iter->iov_offset); } if (rw == READ) { nr = file->f_op->read(file, iovec.iov_base, iovec.iov_len, &kiocb->ki_pos); } else { nr = file->f_op->write(file, iovec.iov_base, iovec.iov_len, &kiocb->ki_pos); } if (iov_iter_is_bvec(iter)) kunmap(iter->bvec->bv_page); if (nr < 0) { if (!ret) ret = nr; break; } ret += nr; if (nr != iovec.iov_len) break; iov_iter_advance(iter, nr); } return ret; } static void io_req_map_rw(struct io_kiocb *req, ssize_t io_size, struct iovec *iovec, struct iovec *fast_iov, struct iov_iter *iter) { req->io->rw.nr_segs = iter->nr_segs; req->io->rw.size = io_size; req->io->rw.iov = iovec; if (!req->io->rw.iov) { req->io->rw.iov = req->io->rw.fast_iov; memcpy(req->io->rw.iov, fast_iov, sizeof(struct iovec) * iter->nr_segs); } } static int io_alloc_async_ctx(struct io_kiocb *req) { if (!io_op_defs[req->opcode].async_ctx) return 0; req->io = kmalloc(sizeof(*req->io), GFP_KERNEL); return req->io == NULL; } static void io_rw_async(struct io_wq_work **workptr) { struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work); struct iovec *iov = NULL; if (req->io->rw.iov != req->io->rw.fast_iov) iov = req->io->rw.iov; io_wq_submit_work(workptr); kfree(iov); } static int io_setup_async_rw(struct io_kiocb *req, ssize_t io_size, struct iovec *iovec, struct iovec *fast_iov, struct iov_iter *iter) { if (req->opcode == IORING_OP_READ_FIXED || req->opcode == IORING_OP_WRITE_FIXED) return 0; if (!req->io && io_alloc_async_ctx(req)) return -ENOMEM; io_req_map_rw(req, io_size, iovec, fast_iov, iter); req->work.func = io_rw_async; return 0; } static int io_read_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool force_nonblock) { struct io_async_ctx *io; struct iov_iter iter; ssize_t ret; ret = io_prep_rw(req, sqe, force_nonblock); if (ret) return ret; if (unlikely(!(req->file->f_mode & FMODE_READ))) return -EBADF; if (!req->io) return 0; io = req->io; io->rw.iov = io->rw.fast_iov; req->io = NULL; ret = io_import_iovec(READ, req, &io->rw.iov, &iter); req->io = io; if (ret < 0) return ret; io_req_map_rw(req, ret, io->rw.iov, io->rw.fast_iov, &iter); return 0; } static int io_read(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw.kiocb; struct iov_iter iter; size_t iov_count; ssize_t io_size, ret; ret = io_import_iovec(READ, req, &iovec, &iter); if (ret < 0) return ret; /* Ensure we clear previously set non-block flag */ if (!force_nonblock) req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT; req->result = 0; io_size = ret; if (req->flags & REQ_F_LINK) req->result = io_size; /* * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so * we know to async punt it even if it was opened O_NONBLOCK */ if (force_nonblock && !io_file_supports_async(req->file)) { req->flags |= REQ_F_MUST_PUNT; goto copy_iov; } iov_count = iov_iter_count(&iter); ret = rw_verify_area(READ, req->file, &kiocb->ki_pos, iov_count); if (!ret) { ssize_t ret2; if (req->file->f_op->read_iter) ret2 = call_read_iter(req->file, kiocb, &iter); else ret2 = loop_rw_iter(READ, req->file, kiocb, &iter); /* Catch -EAGAIN return for forced non-blocking submission */ if (!force_nonblock || ret2 != -EAGAIN) { kiocb_done(kiocb, ret2, nxt, req->in_async); } else { copy_iov: ret = io_setup_async_rw(req, io_size, iovec, inline_vecs, &iter); if (ret) goto out_free; return -EAGAIN; } } out_free: if (!io_wq_current_is_worker()) kfree(iovec); return ret; } static int io_write_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool force_nonblock) { struct io_async_ctx *io; struct iov_iter iter; ssize_t ret; ret = io_prep_rw(req, sqe, force_nonblock); if (ret) return ret; if (unlikely(!(req->file->f_mode & FMODE_WRITE))) return -EBADF; if (!req->io) return 0; io = req->io; io->rw.iov = io->rw.fast_iov; req->io = NULL; ret = io_import_iovec(WRITE, req, &io->rw.iov, &iter); req->io = io; if (ret < 0) return ret; io_req_map_rw(req, ret, io->rw.iov, io->rw.fast_iov, &iter); return 0; } static int io_write(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs; struct kiocb *kiocb = &req->rw.kiocb; struct iov_iter iter; size_t iov_count; ssize_t ret, io_size; ret = io_import_iovec(WRITE, req, &iovec, &iter); if (ret < 0) return ret; /* Ensure we clear previously set non-block flag */ if (!force_nonblock) req->rw.kiocb.ki_flags &= ~IOCB_NOWAIT; req->result = 0; io_size = ret; if (req->flags & REQ_F_LINK) req->result = io_size; /* * If the file doesn't support async, mark it as REQ_F_MUST_PUNT so * we know to async punt it even if it was opened O_NONBLOCK */ if (force_nonblock && !io_file_supports_async(req->file)) { req->flags |= REQ_F_MUST_PUNT; goto copy_iov; } /* file path doesn't support NOWAIT for non-direct_IO */ if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT) && (req->flags & REQ_F_ISREG)) goto copy_iov; iov_count = iov_iter_count(&iter); ret = rw_verify_area(WRITE, req->file, &kiocb->ki_pos, iov_count); if (!ret) { ssize_t ret2; /* * Open-code file_start_write here to grab freeze protection, * which will be released by another thread in * io_complete_rw(). Fool lockdep by telling it the lock got * released so that it doesn't complain about the held lock when * we return to userspace. */ if (req->flags & REQ_F_ISREG) { __sb_start_write(file_inode(req->file)->i_sb, SB_FREEZE_WRITE, true); __sb_writers_release(file_inode(req->file)->i_sb, SB_FREEZE_WRITE); } kiocb->ki_flags |= IOCB_WRITE; if (req->file->f_op->write_iter) ret2 = call_write_iter(req->file, kiocb, &iter); else ret2 = loop_rw_iter(WRITE, req->file, kiocb, &iter); if (!force_nonblock || ret2 != -EAGAIN) { kiocb_done(kiocb, ret2, nxt, req->in_async); } else { copy_iov: ret = io_setup_async_rw(req, io_size, iovec, inline_vecs, &iter); if (ret) goto out_free; return -EAGAIN; } } out_free: if (!io_wq_current_is_worker()) kfree(iovec); return ret; } /* * IORING_OP_NOP just posts a completion event, nothing else. */ static int io_nop(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; io_cqring_add_event(req, 0); io_put_req(req); return 0; } static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; if (!req->file) return -EBADF; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index)) return -EINVAL; req->sync.flags = READ_ONCE(sqe->fsync_flags); if (unlikely(req->sync.flags & ~IORING_FSYNC_DATASYNC)) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->len); return 0; } static bool io_req_cancelled(struct io_kiocb *req) { if (req->work.flags & IO_WQ_WORK_CANCEL) { req_set_fail_links(req); io_cqring_add_event(req, -ECANCELED); io_put_req(req); return true; } return false; } static void io_link_work_cb(struct io_wq_work **workptr) { struct io_wq_work *work = *workptr; struct io_kiocb *link = work->data; io_queue_linked_timeout(link); work->func = io_wq_submit_work; } static void io_wq_assign_next(struct io_wq_work **workptr, struct io_kiocb *nxt) { struct io_kiocb *link; io_prep_async_work(nxt, &link); *workptr = &nxt->work; if (link) { nxt->work.flags |= IO_WQ_WORK_CB; nxt->work.func = io_link_work_cb; nxt->work.data = link; } } static void io_fsync_finish(struct io_wq_work **workptr) { struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work); loff_t end = req->sync.off + req->sync.len; struct io_kiocb *nxt = NULL; int ret; if (io_req_cancelled(req)) return; ret = vfs_fsync_range(req->file, req->sync.off, end > 0 ? end : LLONG_MAX, req->sync.flags & IORING_FSYNC_DATASYNC); if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, &nxt); if (nxt) io_wq_assign_next(workptr, nxt); } static int io_fsync(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { struct io_wq_work *work, *old_work; /* fsync always requires a blocking context */ if (force_nonblock) { io_put_req(req); req->work.func = io_fsync_finish; return -EAGAIN; } work = old_work = &req->work; io_fsync_finish(&work); if (work && work != old_work) *nxt = container_of(work, struct io_kiocb, work); return 0; } static void io_fallocate_finish(struct io_wq_work **workptr) { struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work); struct io_kiocb *nxt = NULL; int ret; ret = vfs_fallocate(req->file, req->sync.mode, req->sync.off, req->sync.len); if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, &nxt); if (nxt) io_wq_assign_next(workptr, nxt); } static int io_fallocate_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (sqe->ioprio || sqe->buf_index || sqe->rw_flags) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->addr); req->sync.mode = READ_ONCE(sqe->len); return 0; } static int io_fallocate(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { struct io_wq_work *work, *old_work; /* fallocate always requiring blocking context */ if (force_nonblock) { io_put_req(req); req->work.func = io_fallocate_finish; return -EAGAIN; } work = old_work = &req->work; io_fallocate_finish(&work); if (work && work != old_work) *nxt = container_of(work, struct io_kiocb, work); return 0; } static int io_openat_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { int ret; if (sqe->ioprio || sqe->buf_index) return -EINVAL; req->open.dfd = READ_ONCE(sqe->fd); req->open.mode = READ_ONCE(sqe->len); req->open.fname = u64_to_user_ptr(READ_ONCE(sqe->addr)); req->open.flags = READ_ONCE(sqe->open_flags); req->open.filename = getname(req->open.fname); if (IS_ERR(req->open.filename)) { ret = PTR_ERR(req->open.filename); req->open.filename = NULL; return ret; } return 0; } static int io_openat(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { struct open_flags op; struct open_how how; struct file *file; int ret; if (force_nonblock) { req->work.flags |= IO_WQ_WORK_NEEDS_FILES; return -EAGAIN; } how = build_open_how(req->open.flags, req->open.mode); ret = build_open_flags(&how, &op); if (ret) goto err; ret = get_unused_fd_flags(how.flags); if (ret < 0) goto err; file = do_filp_open(req->open.dfd, req->open.filename, &op); if (IS_ERR(file)) { put_unused_fd(ret); ret = PTR_ERR(file); } else { fsnotify_open(file); fd_install(ret, file); } err: putname(req->open.filename); if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, nxt); return 0; } static int io_madvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU) if (sqe->ioprio || sqe->buf_index || sqe->off) return -EINVAL; req->madvise.addr = READ_ONCE(sqe->addr); req->madvise.len = READ_ONCE(sqe->len); req->madvise.advice = READ_ONCE(sqe->fadvise_advice); return 0; #else return -EOPNOTSUPP; #endif } static int io_madvise(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { #if defined(CONFIG_ADVISE_SYSCALLS) && defined(CONFIG_MMU) struct io_madvise *ma = &req->madvise; int ret; if (force_nonblock) return -EAGAIN; ret = do_madvise(ma->addr, ma->len, ma->advice); if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, nxt); return 0; #else return -EOPNOTSUPP; #endif } static int io_fadvise_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (sqe->ioprio || sqe->buf_index || sqe->addr) return -EINVAL; req->fadvise.offset = READ_ONCE(sqe->off); req->fadvise.len = READ_ONCE(sqe->len); req->fadvise.advice = READ_ONCE(sqe->fadvise_advice); return 0; } static int io_fadvise(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { struct io_fadvise *fa = &req->fadvise; int ret; /* DONTNEED may block, others _should_ not */ if (fa->advice == POSIX_FADV_DONTNEED && force_nonblock) return -EAGAIN; ret = vfs_fadvise(req->file, fa->offset, fa->len, fa->advice); if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, nxt); return 0; } static int io_statx_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { unsigned lookup_flags; int ret; if (sqe->ioprio || sqe->buf_index) return -EINVAL; req->open.dfd = READ_ONCE(sqe->fd); req->open.mask = READ_ONCE(sqe->len); req->open.fname = u64_to_user_ptr(READ_ONCE(sqe->addr)); req->open.buffer = u64_to_user_ptr(READ_ONCE(sqe->addr2)); req->open.flags = READ_ONCE(sqe->statx_flags); if (vfs_stat_set_lookup_flags(&lookup_flags, req->open.flags)) return -EINVAL; req->open.filename = getname_flags(req->open.fname, lookup_flags, NULL); if (IS_ERR(req->open.filename)) { ret = PTR_ERR(req->open.filename); req->open.filename = NULL; return ret; } return 0; } static int io_statx(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { struct io_open *ctx = &req->open; unsigned lookup_flags; struct path path; struct kstat stat; int ret; if (force_nonblock) return -EAGAIN; if (vfs_stat_set_lookup_flags(&lookup_flags, ctx->flags)) return -EINVAL; retry: /* filename_lookup() drops it, keep a reference */ ctx->filename->refcnt++; ret = filename_lookup(ctx->dfd, ctx->filename, lookup_flags, &path, NULL); if (ret) goto err; ret = vfs_getattr(&path, &stat, ctx->mask, ctx->flags); path_put(&path); if (retry_estale(ret, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } if (!ret) ret = cp_statx(&stat, ctx->buffer); err: putname(ctx->filename); if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, nxt); return 0; } static int io_close_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { /* * If we queue this for async, it must not be cancellable. That would * leave the 'file' in an undeterminate state. */ req->work.flags |= IO_WQ_WORK_NO_CANCEL; if (sqe->ioprio || sqe->off || sqe->addr || sqe->len || sqe->rw_flags || sqe->buf_index) return -EINVAL; if (sqe->flags & IOSQE_FIXED_FILE) return -EINVAL; req->close.fd = READ_ONCE(sqe->fd); if (req->file->f_op == &io_uring_fops || req->close.fd == req->ring_fd) return -EBADF; return 0; } static void io_close_finish(struct io_wq_work **workptr) { struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work); struct io_kiocb *nxt = NULL; /* Invoked with files, we need to do the close */ if (req->work.files) { int ret; ret = filp_close(req->close.put_file, req->work.files); if (ret < 0) { req_set_fail_links(req); } io_cqring_add_event(req, ret); } fput(req->close.put_file); /* we bypassed the re-issue, drop the submission reference */ io_put_req(req); io_put_req_find_next(req, &nxt); if (nxt) io_wq_assign_next(workptr, nxt); } static int io_close(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { int ret; req->close.put_file = NULL; ret = __close_fd_get_file(req->close.fd, &req->close.put_file); if (ret < 0) return ret; /* if the file has a flush method, be safe and punt to async */ if (req->close.put_file->f_op->flush && !io_wq_current_is_worker()) { req->work.flags |= IO_WQ_WORK_NEEDS_FILES; goto eagain; } /* * No ->flush(), safely close from here and just punt the * fput() to async context. */ ret = filp_close(req->close.put_file, current->files); if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); if (io_wq_current_is_worker()) { struct io_wq_work *old_work, *work; old_work = work = &req->work; io_close_finish(&work); if (work && work != old_work) *nxt = container_of(work, struct io_kiocb, work); return 0; } eagain: req->work.func = io_close_finish; return -EAGAIN; } static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; if (!req->file) return -EBADF; if (unlikely(ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index)) return -EINVAL; req->sync.off = READ_ONCE(sqe->off); req->sync.len = READ_ONCE(sqe->len); req->sync.flags = READ_ONCE(sqe->sync_range_flags); return 0; } static void io_sync_file_range_finish(struct io_wq_work **workptr) { struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work); struct io_kiocb *nxt = NULL; int ret; if (io_req_cancelled(req)) return; ret = sync_file_range(req->file, req->sync.off, req->sync.len, req->sync.flags); if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, &nxt); if (nxt) io_wq_assign_next(workptr, nxt); } static int io_sync_file_range(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { struct io_wq_work *work, *old_work; /* sync_file_range always requires a blocking context */ if (force_nonblock) { io_put_req(req); req->work.func = io_sync_file_range_finish; return -EAGAIN; } work = old_work = &req->work; io_sync_file_range_finish(&work); if (work && work != old_work) *nxt = container_of(work, struct io_kiocb, work); return 0; } #if defined(CONFIG_NET) static void io_sendrecv_async(struct io_wq_work **workptr) { struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work); struct iovec *iov = NULL; if (req->io->rw.iov != req->io->rw.fast_iov) iov = req->io->msg.iov; io_wq_submit_work(workptr); kfree(iov); } #endif static int io_sendmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_NET) struct io_sr_msg *sr = &req->sr_msg; struct io_async_ctx *io = req->io; sr->msg_flags = READ_ONCE(sqe->msg_flags); sr->msg = u64_to_user_ptr(READ_ONCE(sqe->addr)); sr->len = READ_ONCE(sqe->len); if (!io || req->opcode == IORING_OP_SEND) return 0; io->msg.iov = io->msg.fast_iov; return sendmsg_copy_msghdr(&io->msg.msg, sr->msg, sr->msg_flags, &io->msg.iov); #else return -EOPNOTSUPP; #endif } static int io_sendmsg(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { #if defined(CONFIG_NET) struct io_async_msghdr *kmsg = NULL; struct socket *sock; int ret; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sock = sock_from_file(req->file, &ret); if (sock) { struct io_async_ctx io; struct sockaddr_storage addr; unsigned flags; if (req->io) { kmsg = &req->io->msg; kmsg->msg.msg_name = &addr; /* if iov is set, it's allocated already */ if (!kmsg->iov) kmsg->iov = kmsg->fast_iov; kmsg->msg.msg_iter.iov = kmsg->iov; } else { struct io_sr_msg *sr = &req->sr_msg; kmsg = &io.msg; kmsg->msg.msg_name = &addr; io.msg.iov = io.msg.fast_iov; ret = sendmsg_copy_msghdr(&io.msg.msg, sr->msg, sr->msg_flags, &io.msg.iov); if (ret) return ret; } flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (force_nonblock) flags |= MSG_DONTWAIT; ret = __sys_sendmsg_sock(sock, &kmsg->msg, flags); if (force_nonblock && ret == -EAGAIN) { if (req->io) return -EAGAIN; if (io_alloc_async_ctx(req)) return -ENOMEM; memcpy(&req->io->msg, &io.msg, sizeof(io.msg)); req->work.func = io_sendrecv_async; return -EAGAIN; } if (ret == -ERESTARTSYS) ret = -EINTR; } if (!io_wq_current_is_worker() && kmsg && kmsg->iov != kmsg->fast_iov) kfree(kmsg->iov); io_cqring_add_event(req, ret); if (ret < 0) req_set_fail_links(req); io_put_req_find_next(req, nxt); return 0; #else return -EOPNOTSUPP; #endif } static int io_send(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { #if defined(CONFIG_NET) struct socket *sock; int ret; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sock = sock_from_file(req->file, &ret); if (sock) { struct io_sr_msg *sr = &req->sr_msg; struct msghdr msg; struct iovec iov; unsigned flags; ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter); if (ret) return ret; msg.msg_name = NULL; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_namelen = 0; flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (force_nonblock) flags |= MSG_DONTWAIT; ret = __sys_sendmsg_sock(sock, &msg, flags); if (force_nonblock && ret == -EAGAIN) return -EAGAIN; if (ret == -ERESTARTSYS) ret = -EINTR; } io_cqring_add_event(req, ret); if (ret < 0) req_set_fail_links(req); io_put_req_find_next(req, nxt); return 0; #else return -EOPNOTSUPP; #endif } static int io_recvmsg_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_NET) struct io_sr_msg *sr = &req->sr_msg; struct io_async_ctx *io = req->io; sr->msg_flags = READ_ONCE(sqe->msg_flags); sr->msg = u64_to_user_ptr(READ_ONCE(sqe->addr)); if (!io || req->opcode == IORING_OP_RECV) return 0; io->msg.iov = io->msg.fast_iov; return recvmsg_copy_msghdr(&io->msg.msg, sr->msg, sr->msg_flags, &io->msg.uaddr, &io->msg.iov); #else return -EOPNOTSUPP; #endif } static int io_recvmsg(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { #if defined(CONFIG_NET) struct io_async_msghdr *kmsg = NULL; struct socket *sock; int ret; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sock = sock_from_file(req->file, &ret); if (sock) { struct io_async_ctx io; struct sockaddr_storage addr; unsigned flags; if (req->io) { kmsg = &req->io->msg; kmsg->msg.msg_name = &addr; /* if iov is set, it's allocated already */ if (!kmsg->iov) kmsg->iov = kmsg->fast_iov; kmsg->msg.msg_iter.iov = kmsg->iov; } else { struct io_sr_msg *sr = &req->sr_msg; kmsg = &io.msg; kmsg->msg.msg_name = &addr; io.msg.iov = io.msg.fast_iov; ret = recvmsg_copy_msghdr(&io.msg.msg, sr->msg, sr->msg_flags, &io.msg.uaddr, &io.msg.iov); if (ret) return ret; } flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (force_nonblock) flags |= MSG_DONTWAIT; ret = __sys_recvmsg_sock(sock, &kmsg->msg, req->sr_msg.msg, kmsg->uaddr, flags); if (force_nonblock && ret == -EAGAIN) { if (req->io) return -EAGAIN; if (io_alloc_async_ctx(req)) return -ENOMEM; memcpy(&req->io->msg, &io.msg, sizeof(io.msg)); req->work.func = io_sendrecv_async; return -EAGAIN; } if (ret == -ERESTARTSYS) ret = -EINTR; } if (!io_wq_current_is_worker() && kmsg && kmsg->iov != kmsg->fast_iov) kfree(kmsg->iov); io_cqring_add_event(req, ret); if (ret < 0) req_set_fail_links(req); io_put_req_find_next(req, nxt); return 0; #else return -EOPNOTSUPP; #endif } static int io_recv(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { #if defined(CONFIG_NET) struct socket *sock; int ret; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; sock = sock_from_file(req->file, &ret); if (sock) { struct io_sr_msg *sr = &req->sr_msg; struct msghdr msg; struct iovec iov; unsigned flags; ret = import_single_range(READ, sr->buf, sr->len, &iov, &msg.msg_iter); if (ret) return ret; msg.msg_name = NULL; msg.msg_control = NULL; msg.msg_controllen = 0; msg.msg_namelen = 0; msg.msg_iocb = NULL; msg.msg_flags = 0; flags = req->sr_msg.msg_flags; if (flags & MSG_DONTWAIT) req->flags |= REQ_F_NOWAIT; else if (force_nonblock) flags |= MSG_DONTWAIT; ret = __sys_recvmsg_sock(sock, &msg, NULL, NULL, flags); if (force_nonblock && ret == -EAGAIN) return -EAGAIN; if (ret == -ERESTARTSYS) ret = -EINTR; } io_cqring_add_event(req, ret); if (ret < 0) req_set_fail_links(req); io_put_req_find_next(req, nxt); return 0; #else return -EOPNOTSUPP; #endif } static int io_accept_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_NET) struct io_accept *accept = &req->accept; if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL))) return -EINVAL; if (sqe->ioprio || sqe->len || sqe->buf_index) return -EINVAL; accept->addr = u64_to_user_ptr(READ_ONCE(sqe->addr)); accept->addr_len = u64_to_user_ptr(READ_ONCE(sqe->addr2)); accept->flags = READ_ONCE(sqe->accept_flags); return 0; #else return -EOPNOTSUPP; #endif } #if defined(CONFIG_NET) static int __io_accept(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { struct io_accept *accept = &req->accept; unsigned file_flags; int ret; file_flags = force_nonblock ? O_NONBLOCK : 0; ret = __sys_accept4_file(req->file, file_flags, accept->addr, accept->addr_len, accept->flags); if (ret == -EAGAIN && force_nonblock) return -EAGAIN; if (ret == -ERESTARTSYS) ret = -EINTR; if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, nxt); return 0; } static void io_accept_finish(struct io_wq_work **workptr) { struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work); struct io_kiocb *nxt = NULL; if (io_req_cancelled(req)) return; __io_accept(req, &nxt, false); if (nxt) io_wq_assign_next(workptr, nxt); } #endif static int io_accept(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { #if defined(CONFIG_NET) int ret; ret = __io_accept(req, nxt, force_nonblock); if (ret == -EAGAIN && force_nonblock) { req->work.func = io_accept_finish; req->work.flags |= IO_WQ_WORK_NEEDS_FILES; io_put_req(req); return -EAGAIN; } return 0; #else return -EOPNOTSUPP; #endif } static int io_connect_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { #if defined(CONFIG_NET) struct io_connect *conn = &req->connect; struct io_async_ctx *io = req->io; if (unlikely(req->ctx->flags & (IORING_SETUP_IOPOLL|IORING_SETUP_SQPOLL))) return -EINVAL; if (sqe->ioprio || sqe->len || sqe->buf_index || sqe->rw_flags) return -EINVAL; conn->addr = u64_to_user_ptr(READ_ONCE(sqe->addr)); conn->addr_len = READ_ONCE(sqe->addr2); if (!io) return 0; return move_addr_to_kernel(conn->addr, conn->addr_len, &io->connect.address); #else return -EOPNOTSUPP; #endif } static int io_connect(struct io_kiocb *req, struct io_kiocb **nxt, bool force_nonblock) { #if defined(CONFIG_NET) struct io_async_ctx __io, *io; unsigned file_flags; int ret; if (req->io) { io = req->io; } else { ret = move_addr_to_kernel(req->connect.addr, req->connect.addr_len, &__io.connect.address); if (ret) goto out; io = &__io; } file_flags = force_nonblock ? O_NONBLOCK : 0; ret = __sys_connect_file(req->file, &io->connect.address, req->connect.addr_len, file_flags); if ((ret == -EAGAIN || ret == -EINPROGRESS) && force_nonblock) { if (req->io) return -EAGAIN; if (io_alloc_async_ctx(req)) { ret = -ENOMEM; goto out; } memcpy(&req->io->connect, &__io.connect, sizeof(__io.connect)); return -EAGAIN; } if (ret == -ERESTARTSYS) ret = -EINTR; out: if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req_find_next(req, nxt); return 0; #else return -EOPNOTSUPP; #endif } static void io_poll_remove_one(struct io_kiocb *req) { struct io_poll_iocb *poll = &req->poll; spin_lock(&poll->head->lock); WRITE_ONCE(poll->canceled, true); if (!list_empty(&poll->wait.entry)) { list_del_init(&poll->wait.entry); io_queue_async_work(req); } spin_unlock(&poll->head->lock); hash_del(&req->hash_node); } static void io_poll_remove_all(struct io_ring_ctx *ctx) { struct hlist_node *tmp; struct io_kiocb *req; int i; spin_lock_irq(&ctx->completion_lock); for (i = 0; i < (1U << ctx->cancel_hash_bits); i++) { struct hlist_head *list; list = &ctx->cancel_hash[i]; hlist_for_each_entry_safe(req, tmp, list, hash_node) io_poll_remove_one(req); } spin_unlock_irq(&ctx->completion_lock); } static int io_poll_cancel(struct io_ring_ctx *ctx, __u64 sqe_addr) { struct hlist_head *list; struct io_kiocb *req; list = &ctx->cancel_hash[hash_long(sqe_addr, ctx->cancel_hash_bits)]; hlist_for_each_entry(req, list, hash_node) { if (sqe_addr == req->user_data) { io_poll_remove_one(req); return 0; } } return -ENOENT; } static int io_poll_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index || sqe->poll_events) return -EINVAL; req->poll.addr = READ_ONCE(sqe->addr); return 0; } /* * Find a running poll command that matches one specified in sqe->addr, * and remove it if found. */ static int io_poll_remove(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; u64 addr; int ret; addr = req->poll.addr; spin_lock_irq(&ctx->completion_lock); ret = io_poll_cancel(ctx, addr); spin_unlock_irq(&ctx->completion_lock); io_cqring_add_event(req, ret); if (ret < 0) req_set_fail_links(req); io_put_req(req); return 0; } static void io_poll_complete(struct io_kiocb *req, __poll_t mask, int error) { struct io_ring_ctx *ctx = req->ctx; req->poll.done = true; if (error) io_cqring_fill_event(req, error); else io_cqring_fill_event(req, mangle_poll(mask)); io_commit_cqring(ctx); } static void io_poll_complete_work(struct io_wq_work **workptr) { struct io_wq_work *work = *workptr; struct io_kiocb *req = container_of(work, struct io_kiocb, work); struct io_poll_iocb *poll = &req->poll; struct poll_table_struct pt = { ._key = poll->events }; struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *nxt = NULL; __poll_t mask = 0; int ret = 0; if (work->flags & IO_WQ_WORK_CANCEL) { WRITE_ONCE(poll->canceled, true); ret = -ECANCELED; } else if (READ_ONCE(poll->canceled)) { ret = -ECANCELED; } if (ret != -ECANCELED) mask = vfs_poll(poll->file, &pt) & poll->events; /* * Note that ->ki_cancel callers also delete iocb from active_reqs after * calling ->ki_cancel. We need the ctx_lock roundtrip here to * synchronize with them. In the cancellation case the list_del_init * itself is not actually needed, but harmless so we keep it in to * avoid further branches in the fast path. */ spin_lock_irq(&ctx->completion_lock); if (!mask && ret != -ECANCELED) { add_wait_queue(poll->head, &poll->wait); spin_unlock_irq(&ctx->completion_lock); return; } hash_del(&req->hash_node); io_poll_complete(req, mask, ret); spin_unlock_irq(&ctx->completion_lock); io_cqring_ev_posted(ctx); if (ret < 0) req_set_fail_links(req); io_put_req_find_next(req, &nxt); if (nxt) io_wq_assign_next(workptr, nxt); } static void __io_poll_flush(struct io_ring_ctx *ctx, struct llist_node *nodes) { struct io_kiocb *req, *tmp; struct req_batch rb; rb.to_free = rb.need_iter = 0; spin_lock_irq(&ctx->completion_lock); llist_for_each_entry_safe(req, tmp, nodes, llist_node) { hash_del(&req->hash_node); io_poll_complete(req, req->result, 0); if (refcount_dec_and_test(&req->refs) && !io_req_multi_free(&rb, req)) { req->flags |= REQ_F_COMP_LOCKED; io_free_req(req); } } spin_unlock_irq(&ctx->completion_lock); io_cqring_ev_posted(ctx); io_free_req_many(ctx, &rb); } static void io_poll_flush(struct io_wq_work **workptr) { struct io_kiocb *req = container_of(*workptr, struct io_kiocb, work); struct llist_node *nodes; nodes = llist_del_all(&req->ctx->poll_llist); if (nodes) __io_poll_flush(req->ctx, nodes); } static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync, void *key) { struct io_poll_iocb *poll = wait->private; struct io_kiocb *req = container_of(poll, struct io_kiocb, poll); struct io_ring_ctx *ctx = req->ctx; __poll_t mask = key_to_poll(key); /* for instances that support it check for an event match first: */ if (mask && !(mask & poll->events)) return 0; list_del_init(&poll->wait.entry); /* * Run completion inline if we can. We're using trylock here because * we are violating the completion_lock -> poll wq lock ordering. * If we have a link timeout we're going to need the completion_lock * for finalizing the request, mark us as having grabbed that already. */ if (mask) { unsigned long flags; if (llist_empty(&ctx->poll_llist) && spin_trylock_irqsave(&ctx->completion_lock, flags)) { hash_del(&req->hash_node); io_poll_complete(req, mask, 0); req->flags |= REQ_F_COMP_LOCKED; io_put_req(req); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); req = NULL; } else { req->result = mask; req->llist_node.next = NULL; /* if the list wasn't empty, we're done */ if (!llist_add(&req->llist_node, &ctx->poll_llist)) req = NULL; else req->work.func = io_poll_flush; } } if (req) io_queue_async_work(req); return 1; } struct io_poll_table { struct poll_table_struct pt; struct io_kiocb *req; int error; }; static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head, struct poll_table_struct *p) { struct io_poll_table *pt = container_of(p, struct io_poll_table, pt); if (unlikely(pt->req->poll.head)) { pt->error = -EINVAL; return; } pt->error = 0; pt->req->poll.head = head; add_wait_queue(head, &pt->req->poll.wait); } static void io_poll_req_insert(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; struct hlist_head *list; list = &ctx->cancel_hash[hash_long(req->user_data, ctx->cancel_hash_bits)]; hlist_add_head(&req->hash_node, list); } static int io_poll_add_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_poll_iocb *poll = &req->poll; u16 events; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index) return -EINVAL; if (!poll->file) return -EBADF; events = READ_ONCE(sqe->poll_events); poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP; return 0; } static int io_poll_add(struct io_kiocb *req, struct io_kiocb **nxt) { struct io_poll_iocb *poll = &req->poll; struct io_ring_ctx *ctx = req->ctx; struct io_poll_table ipt; bool cancel = false; __poll_t mask; INIT_IO_WORK(&req->work, io_poll_complete_work); INIT_HLIST_NODE(&req->hash_node); poll->head = NULL; poll->done = false; poll->canceled = false; ipt.pt._qproc = io_poll_queue_proc; ipt.pt._key = poll->events; ipt.req = req; ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */ /* initialized the list so that we can do list_empty checks */ INIT_LIST_HEAD(&poll->wait.entry); init_waitqueue_func_entry(&poll->wait, io_poll_wake); poll->wait.private = poll; INIT_LIST_HEAD(&req->list); mask = vfs_poll(poll->file, &ipt.pt) & poll->events; spin_lock_irq(&ctx->completion_lock); if (likely(poll->head)) { spin_lock(&poll->head->lock); if (unlikely(list_empty(&poll->wait.entry))) { if (ipt.error) cancel = true; ipt.error = 0; mask = 0; } if (mask || ipt.error) list_del_init(&poll->wait.entry); else if (cancel) WRITE_ONCE(poll->canceled, true); else if (!poll->done) /* actually waiting for an event */ io_poll_req_insert(req); spin_unlock(&poll->head->lock); } if (mask) { /* no async, we'd stolen it */ ipt.error = 0; io_poll_complete(req, mask, 0); } spin_unlock_irq(&ctx->completion_lock); if (mask) { io_cqring_ev_posted(ctx); io_put_req_find_next(req, nxt); } return ipt.error; } static enum hrtimer_restart io_timeout_fn(struct hrtimer *timer) { struct io_timeout_data *data = container_of(timer, struct io_timeout_data, timer); struct io_kiocb *req = data->req; struct io_ring_ctx *ctx = req->ctx; unsigned long flags; atomic_inc(&ctx->cq_timeouts); spin_lock_irqsave(&ctx->completion_lock, flags); /* * We could be racing with timeout deletion. If the list is empty, * then timeout lookup already found it and will be handling it. */ if (!list_empty(&req->list)) { struct io_kiocb *prev; /* * Adjust the reqs sequence before the current one because it * will consume a slot in the cq_ring and the cq_tail * pointer will be increased, otherwise other timeout reqs may * return in advance without waiting for enough wait_nr. */ prev = req; list_for_each_entry_continue_reverse(prev, &ctx->timeout_list, list) prev->sequence++; list_del_init(&req->list); } io_cqring_fill_event(req, -ETIME); io_commit_cqring(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); req_set_fail_links(req); io_put_req(req); return HRTIMER_NORESTART; } static int io_timeout_cancel(struct io_ring_ctx *ctx, __u64 user_data) { struct io_kiocb *req; int ret = -ENOENT; list_for_each_entry(req, &ctx->timeout_list, list) { if (user_data == req->user_data) { list_del_init(&req->list); ret = 0; break; } } if (ret == -ENOENT) return ret; ret = hrtimer_try_to_cancel(&req->io->timeout.timer); if (ret == -1) return -EALREADY; req_set_fail_links(req); io_cqring_fill_event(req, -ECANCELED); io_put_req(req); return 0; } static int io_timeout_remove_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->flags || sqe->ioprio || sqe->buf_index || sqe->len) return -EINVAL; req->timeout.addr = READ_ONCE(sqe->addr); req->timeout.flags = READ_ONCE(sqe->timeout_flags); if (req->timeout.flags) return -EINVAL; return 0; } /* * Remove or update an existing timeout command */ static int io_timeout_remove(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; int ret; spin_lock_irq(&ctx->completion_lock); ret = io_timeout_cancel(ctx, req->timeout.addr); io_cqring_fill_event(req, ret); io_commit_cqring(ctx); spin_unlock_irq(&ctx->completion_lock); io_cqring_ev_posted(ctx); if (ret < 0) req_set_fail_links(req); io_put_req(req); return 0; } static int io_timeout_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe, bool is_timeout_link) { struct io_timeout_data *data; unsigned flags; if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->ioprio || sqe->buf_index || sqe->len != 1) return -EINVAL; if (sqe->off && is_timeout_link) return -EINVAL; flags = READ_ONCE(sqe->timeout_flags); if (flags & ~IORING_TIMEOUT_ABS) return -EINVAL; req->timeout.count = READ_ONCE(sqe->off); if (!req->io && io_alloc_async_ctx(req)) return -ENOMEM; data = &req->io->timeout; data->req = req; req->flags |= REQ_F_TIMEOUT; if (get_timespec64(&data->ts, u64_to_user_ptr(sqe->addr))) return -EFAULT; if (flags & IORING_TIMEOUT_ABS) data->mode = HRTIMER_MODE_ABS; else data->mode = HRTIMER_MODE_REL; hrtimer_init(&data->timer, CLOCK_MONOTONIC, data->mode); return 0; } static int io_timeout(struct io_kiocb *req) { unsigned count; struct io_ring_ctx *ctx = req->ctx; struct io_timeout_data *data; struct list_head *entry; unsigned span = 0; data = &req->io->timeout; /* * sqe->off holds how many events that need to occur for this * timeout event to be satisfied. If it isn't set, then this is * a pure timeout request, sequence isn't used. */ count = req->timeout.count; if (!count) { req->flags |= REQ_F_TIMEOUT_NOSEQ; spin_lock_irq(&ctx->completion_lock); entry = ctx->timeout_list.prev; goto add; } req->sequence = ctx->cached_sq_head + count - 1; data->seq_offset = count; /* * Insertion sort, ensuring the first entry in the list is always * the one we need first. */ spin_lock_irq(&ctx->completion_lock); list_for_each_prev(entry, &ctx->timeout_list) { struct io_kiocb *nxt = list_entry(entry, struct io_kiocb, list); unsigned nxt_sq_head; long long tmp, tmp_nxt; u32 nxt_offset = nxt->io->timeout.seq_offset; if (nxt->flags & REQ_F_TIMEOUT_NOSEQ) continue; /* * Since cached_sq_head + count - 1 can overflow, use type long * long to store it. */ tmp = (long long)ctx->cached_sq_head + count - 1; nxt_sq_head = nxt->sequence - nxt_offset + 1; tmp_nxt = (long long)nxt_sq_head + nxt_offset - 1; /* * cached_sq_head may overflow, and it will never overflow twice * once there is some timeout req still be valid. */ if (ctx->cached_sq_head < nxt_sq_head) tmp += UINT_MAX; if (tmp > tmp_nxt) break; /* * Sequence of reqs after the insert one and itself should * be adjusted because each timeout req consumes a slot. */ span++; nxt->sequence++; } req->sequence -= span; add: list_add(&req->list, entry); data->timer.function = io_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); spin_unlock_irq(&ctx->completion_lock); return 0; } static bool io_cancel_cb(struct io_wq_work *work, void *data) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); return req->user_data == (unsigned long) data; } static int io_async_cancel_one(struct io_ring_ctx *ctx, void *sqe_addr) { enum io_wq_cancel cancel_ret; int ret = 0; cancel_ret = io_wq_cancel_cb(ctx->io_wq, io_cancel_cb, sqe_addr); switch (cancel_ret) { case IO_WQ_CANCEL_OK: ret = 0; break; case IO_WQ_CANCEL_RUNNING: ret = -EALREADY; break; case IO_WQ_CANCEL_NOTFOUND: ret = -ENOENT; break; } return ret; } static void io_async_find_and_cancel(struct io_ring_ctx *ctx, struct io_kiocb *req, __u64 sqe_addr, struct io_kiocb **nxt, int success_ret) { unsigned long flags; int ret; ret = io_async_cancel_one(ctx, (void *) (unsigned long) sqe_addr); if (ret != -ENOENT) { spin_lock_irqsave(&ctx->completion_lock, flags); goto done; } spin_lock_irqsave(&ctx->completion_lock, flags); ret = io_timeout_cancel(ctx, sqe_addr); if (ret != -ENOENT) goto done; ret = io_poll_cancel(ctx, sqe_addr); done: if (!ret) ret = success_ret; io_cqring_fill_event(req, ret); io_commit_cqring(ctx); spin_unlock_irqrestore(&ctx->completion_lock, flags); io_cqring_ev_posted(ctx); if (ret < 0) req_set_fail_links(req); io_put_req_find_next(req, nxt); } static int io_async_cancel_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL)) return -EINVAL; if (sqe->flags || sqe->ioprio || sqe->off || sqe->len || sqe->cancel_flags) return -EINVAL; req->cancel.addr = READ_ONCE(sqe->addr); return 0; } static int io_async_cancel(struct io_kiocb *req, struct io_kiocb **nxt) { struct io_ring_ctx *ctx = req->ctx; io_async_find_and_cancel(ctx, req, req->cancel.addr, nxt, 0); return 0; } static int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { if (sqe->flags || sqe->ioprio || sqe->rw_flags) return -EINVAL; req->files_update.offset = READ_ONCE(sqe->off); req->files_update.nr_args = READ_ONCE(sqe->len); if (!req->files_update.nr_args) return -EINVAL; req->files_update.arg = READ_ONCE(sqe->addr); return 0; } static int io_files_update(struct io_kiocb *req, bool force_nonblock) { struct io_ring_ctx *ctx = req->ctx; struct io_uring_files_update up; int ret; if (force_nonblock) { req->work.flags |= IO_WQ_WORK_NEEDS_FILES; return -EAGAIN; } up.offset = req->files_update.offset; up.fds = req->files_update.arg; mutex_lock(&ctx->uring_lock); ret = __io_sqe_files_update(ctx, &up, req->files_update.nr_args); mutex_unlock(&ctx->uring_lock); if (ret < 0) req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req(req); return 0; } static int io_req_defer_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) { ssize_t ret = 0; switch (req->opcode) { case IORING_OP_NOP: break; case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: ret = io_read_prep(req, sqe, true); break; case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: ret = io_write_prep(req, sqe, true); break; case IORING_OP_POLL_ADD: ret = io_poll_add_prep(req, sqe); break; case IORING_OP_POLL_REMOVE: ret = io_poll_remove_prep(req, sqe); break; case IORING_OP_FSYNC: ret = io_prep_fsync(req, sqe); break; case IORING_OP_SYNC_FILE_RANGE: ret = io_prep_sfr(req, sqe); break; case IORING_OP_SENDMSG: case IORING_OP_SEND: ret = io_sendmsg_prep(req, sqe); break; case IORING_OP_RECVMSG: case IORING_OP_RECV: ret = io_recvmsg_prep(req, sqe); break; case IORING_OP_CONNECT: ret = io_connect_prep(req, sqe); break; case IORING_OP_TIMEOUT: ret = io_timeout_prep(req, sqe, false); break; case IORING_OP_TIMEOUT_REMOVE: ret = io_timeout_remove_prep(req, sqe); break; case IORING_OP_ASYNC_CANCEL: ret = io_async_cancel_prep(req, sqe); break; case IORING_OP_LINK_TIMEOUT: ret = io_timeout_prep(req, sqe, true); break; case IORING_OP_ACCEPT: ret = io_accept_prep(req, sqe); break; case IORING_OP_FALLOCATE: ret = io_fallocate_prep(req, sqe); break; case IORING_OP_OPENAT: ret = io_openat_prep(req, sqe); break; case IORING_OP_CLOSE: ret = io_close_prep(req, sqe); break; case IORING_OP_FILES_UPDATE: ret = io_files_update_prep(req, sqe); break; case IORING_OP_STATX: ret = io_statx_prep(req, sqe); break; case IORING_OP_FADVISE: ret = io_fadvise_prep(req, sqe); break; case IORING_OP_MADVISE: ret = io_madvise_prep(req, sqe); break; default: printk_once(KERN_WARNING "io_uring: unhandled opcode %d\n", req->opcode); ret = -EINVAL; break; } return ret; } static int io_req_defer(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; int ret; /* Still need defer if there is pending req in defer list. */ if (!req_need_defer(req) && list_empty(&ctx->defer_list)) return 0; if (!req->io && io_alloc_async_ctx(req)) return -EAGAIN; ret = io_req_defer_prep(req, sqe); if (ret < 0) return ret; spin_lock_irq(&ctx->completion_lock); if (!req_need_defer(req) && list_empty(&ctx->defer_list)) { spin_unlock_irq(&ctx->completion_lock); return 0; } trace_io_uring_defer(ctx, req, req->user_data); list_add_tail(&req->list, &ctx->defer_list); spin_unlock_irq(&ctx->completion_lock); return -EIOCBQUEUED; } static int io_issue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct io_kiocb **nxt, bool force_nonblock) { struct io_ring_ctx *ctx = req->ctx; int ret; switch (req->opcode) { case IORING_OP_NOP: ret = io_nop(req); break; case IORING_OP_READV: case IORING_OP_READ_FIXED: case IORING_OP_READ: if (sqe) { ret = io_read_prep(req, sqe, force_nonblock); if (ret < 0) break; } ret = io_read(req, nxt, force_nonblock); break; case IORING_OP_WRITEV: case IORING_OP_WRITE_FIXED: case IORING_OP_WRITE: if (sqe) { ret = io_write_prep(req, sqe, force_nonblock); if (ret < 0) break; } ret = io_write(req, nxt, force_nonblock); break; case IORING_OP_FSYNC: if (sqe) { ret = io_prep_fsync(req, sqe); if (ret < 0) break; } ret = io_fsync(req, nxt, force_nonblock); break; case IORING_OP_POLL_ADD: if (sqe) { ret = io_poll_add_prep(req, sqe); if (ret) break; } ret = io_poll_add(req, nxt); break; case IORING_OP_POLL_REMOVE: if (sqe) { ret = io_poll_remove_prep(req, sqe); if (ret < 0) break; } ret = io_poll_remove(req); break; case IORING_OP_SYNC_FILE_RANGE: if (sqe) { ret = io_prep_sfr(req, sqe); if (ret < 0) break; } ret = io_sync_file_range(req, nxt, force_nonblock); break; case IORING_OP_SENDMSG: case IORING_OP_SEND: if (sqe) { ret = io_sendmsg_prep(req, sqe); if (ret < 0) break; } if (req->opcode == IORING_OP_SENDMSG) ret = io_sendmsg(req, nxt, force_nonblock); else ret = io_send(req, nxt, force_nonblock); break; case IORING_OP_RECVMSG: case IORING_OP_RECV: if (sqe) { ret = io_recvmsg_prep(req, sqe); if (ret) break; } if (req->opcode == IORING_OP_RECVMSG) ret = io_recvmsg(req, nxt, force_nonblock); else ret = io_recv(req, nxt, force_nonblock); break; case IORING_OP_TIMEOUT: if (sqe) { ret = io_timeout_prep(req, sqe, false); if (ret) break; } ret = io_timeout(req); break; case IORING_OP_TIMEOUT_REMOVE: if (sqe) { ret = io_timeout_remove_prep(req, sqe); if (ret) break; } ret = io_timeout_remove(req); break; case IORING_OP_ACCEPT: if (sqe) { ret = io_accept_prep(req, sqe); if (ret) break; } ret = io_accept(req, nxt, force_nonblock); break; case IORING_OP_CONNECT: if (sqe) { ret = io_connect_prep(req, sqe); if (ret) break; } ret = io_connect(req, nxt, force_nonblock); break; case IORING_OP_ASYNC_CANCEL: if (sqe) { ret = io_async_cancel_prep(req, sqe); if (ret) break; } ret = io_async_cancel(req, nxt); break; case IORING_OP_FALLOCATE: if (sqe) { ret = io_fallocate_prep(req, sqe); if (ret) break; } ret = io_fallocate(req, nxt, force_nonblock); break; case IORING_OP_OPENAT: if (sqe) { ret = io_openat_prep(req, sqe); if (ret) break; } ret = io_openat(req, nxt, force_nonblock); break; case IORING_OP_CLOSE: if (sqe) { ret = io_close_prep(req, sqe); if (ret) break; } ret = io_close(req, nxt, force_nonblock); break; case IORING_OP_FILES_UPDATE: if (sqe) { ret = io_files_update_prep(req, sqe); if (ret) break; } ret = io_files_update(req, force_nonblock); break; case IORING_OP_STATX: if (sqe) { ret = io_statx_prep(req, sqe); if (ret) break; } ret = io_statx(req, nxt, force_nonblock); break; case IORING_OP_FADVISE: if (sqe) { ret = io_fadvise_prep(req, sqe); if (ret) break; } ret = io_fadvise(req, nxt, force_nonblock); break; case IORING_OP_MADVISE: if (sqe) { ret = io_madvise_prep(req, sqe); if (ret) break; } ret = io_madvise(req, nxt, force_nonblock); break; default: ret = -EINVAL; break; } if (ret) return ret; if (ctx->flags & IORING_SETUP_IOPOLL) { const bool in_async = io_wq_current_is_worker(); if (req->result == -EAGAIN) return -EAGAIN; /* workqueue context doesn't hold uring_lock, grab it now */ if (in_async) mutex_lock(&ctx->uring_lock); io_iopoll_req_issued(req); if (in_async) mutex_unlock(&ctx->uring_lock); } return 0; } static void io_wq_submit_work(struct io_wq_work **workptr) { struct io_wq_work *work = *workptr; struct io_kiocb *req = container_of(work, struct io_kiocb, work); struct io_kiocb *nxt = NULL; int ret = 0; /* if NO_CANCEL is set, we must still run the work */ if ((work->flags & (IO_WQ_WORK_CANCEL|IO_WQ_WORK_NO_CANCEL)) == IO_WQ_WORK_CANCEL) { ret = -ECANCELED; } if (!ret) { req->has_user = (work->flags & IO_WQ_WORK_HAS_MM) != 0; req->in_async = true; do { ret = io_issue_sqe(req, NULL, &nxt, false); /* * We can get EAGAIN for polled IO even though we're * forcing a sync submission from here, since we can't * wait for request slots on the block side. */ if (ret != -EAGAIN) break; cond_resched(); } while (1); } /* drop submission reference */ io_put_req(req); if (ret) { req_set_fail_links(req); io_cqring_add_event(req, ret); io_put_req(req); } /* if a dependent link is ready, pass it back */ if (!ret && nxt) io_wq_assign_next(workptr, nxt); } static int io_req_needs_file(struct io_kiocb *req, int fd) { if (!io_op_defs[req->opcode].needs_file) return 0; if (fd == -1 && io_op_defs[req->opcode].fd_non_neg) return 0; return 1; } static inline struct file *io_file_from_index(struct io_ring_ctx *ctx, int index) { struct fixed_file_table *table; table = &ctx->file_data->table[index >> IORING_FILE_TABLE_SHIFT]; return table->files[index & IORING_FILE_TABLE_MASK];; } static int io_req_set_file(struct io_submit_state *state, struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_ring_ctx *ctx = req->ctx; unsigned flags; int fd; flags = READ_ONCE(sqe->flags); fd = READ_ONCE(sqe->fd); if (flags & IOSQE_IO_DRAIN) req->flags |= REQ_F_IO_DRAIN; if (!io_req_needs_file(req, fd)) return 0; if (flags & IOSQE_FIXED_FILE) { if (unlikely(!ctx->file_data || (unsigned) fd >= ctx->nr_user_files)) return -EBADF; fd = array_index_nospec(fd, ctx->nr_user_files); req->file = io_file_from_index(ctx, fd); if (!req->file) return -EBADF; req->flags |= REQ_F_FIXED_FILE; percpu_ref_get(&ctx->file_data->refs); } else { if (req->needs_fixed_file) return -EBADF; trace_io_uring_file_get(ctx, fd); req->file = io_file_get(state, fd); if (unlikely(!req->file)) return -EBADF; } return 0; } static int io_grab_files(struct io_kiocb *req) { int ret = -EBADF; struct io_ring_ctx *ctx = req->ctx; if (!req->ring_file) return -EBADF; rcu_read_lock(); spin_lock_irq(&ctx->inflight_lock); /* * We use the f_ops->flush() handler to ensure that we can flush * out work accessing these files if the fd is closed. Check if * the fd has changed since we started down this path, and disallow * this operation if it has. */ if (fcheck(req->ring_fd) == req->ring_file) { list_add(&req->inflight_entry, &ctx->inflight_list); req->flags |= REQ_F_INFLIGHT; req->work.files = current->files; ret = 0; } spin_unlock_irq(&ctx->inflight_lock); rcu_read_unlock(); return ret; } static enum hrtimer_restart io_link_timeout_fn(struct hrtimer *timer) { struct io_timeout_data *data = container_of(timer, struct io_timeout_data, timer); struct io_kiocb *req = data->req; struct io_ring_ctx *ctx = req->ctx; struct io_kiocb *prev = NULL; unsigned long flags; spin_lock_irqsave(&ctx->completion_lock, flags); /* * We don't expect the list to be empty, that will only happen if we * race with the completion of the linked work. */ if (!list_empty(&req->link_list)) { prev = list_entry(req->link_list.prev, struct io_kiocb, link_list); if (refcount_inc_not_zero(&prev->refs)) { list_del_init(&req->link_list); prev->flags &= ~REQ_F_LINK_TIMEOUT; } else prev = NULL; } spin_unlock_irqrestore(&ctx->completion_lock, flags); if (prev) { req_set_fail_links(prev); io_async_find_and_cancel(ctx, req, prev->user_data, NULL, -ETIME); io_put_req(prev); } else { io_cqring_add_event(req, -ETIME); io_put_req(req); } return HRTIMER_NORESTART; } static void io_queue_linked_timeout(struct io_kiocb *req) { struct io_ring_ctx *ctx = req->ctx; /* * If the list is now empty, then our linked request finished before * we got a chance to setup the timer */ spin_lock_irq(&ctx->completion_lock); if (!list_empty(&req->link_list)) { struct io_timeout_data *data = &req->io->timeout; data->timer.function = io_link_timeout_fn; hrtimer_start(&data->timer, timespec64_to_ktime(data->ts), data->mode); } spin_unlock_irq(&ctx->completion_lock); /* drop submission reference */ io_put_req(req); } static struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req) { struct io_kiocb *nxt; if (!(req->flags & REQ_F_LINK)) return NULL; nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb, link_list); if (!nxt || nxt->opcode != IORING_OP_LINK_TIMEOUT) return NULL; req->flags |= REQ_F_LINK_TIMEOUT; return nxt; } static void __io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_kiocb *linked_timeout; struct io_kiocb *nxt = NULL; int ret; again: linked_timeout = io_prep_linked_timeout(req); ret = io_issue_sqe(req, sqe, &nxt, true); /* * We async punt it if the file wasn't marked NOWAIT, or if the file * doesn't support non-blocking read/write attempts */ if (ret == -EAGAIN && (!(req->flags & REQ_F_NOWAIT) || (req->flags & REQ_F_MUST_PUNT))) { if (req->work.flags & IO_WQ_WORK_NEEDS_FILES) { ret = io_grab_files(req); if (ret) goto err; } /* * Queued up for async execution, worker will release * submit reference when the iocb is actually submitted. */ io_queue_async_work(req); goto done_req; } err: /* drop submission reference */ io_put_req(req); if (linked_timeout) { if (!ret) io_queue_linked_timeout(linked_timeout); else io_put_req(linked_timeout); } /* and drop final reference, if we failed */ if (ret) { io_cqring_add_event(req, ret); req_set_fail_links(req); io_put_req(req); } done_req: if (nxt) { req = nxt; nxt = NULL; goto again; } } static void io_queue_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe) { int ret; if (unlikely(req->ctx->drain_next)) { req->flags |= REQ_F_IO_DRAIN; req->ctx->drain_next = false; } req->ctx->drain_next = (req->flags & REQ_F_DRAIN_LINK); ret = io_req_defer(req, sqe); if (ret) { if (ret != -EIOCBQUEUED) { io_cqring_add_event(req, ret); req_set_fail_links(req); io_double_put_req(req); } } else if (req->flags & REQ_F_FORCE_ASYNC) { /* * Never try inline submit of IOSQE_ASYNC is set, go straight * to async execution. */ req->work.flags |= IO_WQ_WORK_CONCURRENT; io_queue_async_work(req); } else { __io_queue_sqe(req, sqe); } } static inline void io_queue_link_head(struct io_kiocb *req) { if (unlikely(req->flags & REQ_F_FAIL_LINK)) { io_cqring_add_event(req, -ECANCELED); io_double_put_req(req); } else io_queue_sqe(req, NULL); } #define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK| \ IOSQE_IO_HARDLINK | IOSQE_ASYNC) static bool io_submit_sqe(struct io_kiocb *req, const struct io_uring_sqe *sqe, struct io_submit_state *state, struct io_kiocb **link) { struct io_ring_ctx *ctx = req->ctx; unsigned int sqe_flags; int ret; sqe_flags = READ_ONCE(sqe->flags); /* enforce forwards compatibility on users */ if (unlikely(sqe_flags & ~SQE_VALID_FLAGS)) { ret = -EINVAL; goto err_req; } if (sqe_flags & IOSQE_ASYNC) req->flags |= REQ_F_FORCE_ASYNC; ret = io_req_set_file(state, req, sqe); if (unlikely(ret)) { err_req: io_cqring_add_event(req, ret); io_double_put_req(req); return false; } /* * If we already have a head request, queue this one for async * submittal once the head completes. If we don't have a head but * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be * submitted sync once the chain is complete. If none of those * conditions are true (normal request), then just queue it. */ if (*link) { struct io_kiocb *head = *link; if (sqe_flags & IOSQE_IO_DRAIN) head->flags |= REQ_F_DRAIN_LINK | REQ_F_IO_DRAIN; if (sqe_flags & IOSQE_IO_HARDLINK) req->flags |= REQ_F_HARDLINK; if (io_alloc_async_ctx(req)) { ret = -EAGAIN; goto err_req; } ret = io_req_defer_prep(req, sqe); if (ret) { /* fail even hard links since we don't submit */ head->flags |= REQ_F_FAIL_LINK; goto err_req; } trace_io_uring_link(ctx, req, head); list_add_tail(&req->link_list, &head->link_list); /* last request of a link, enqueue the link */ if (!(sqe_flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK))) { io_queue_link_head(head); *link = NULL; } } else if (sqe_flags & (IOSQE_IO_LINK|IOSQE_IO_HARDLINK)) { req->flags |= REQ_F_LINK; if (sqe_flags & IOSQE_IO_HARDLINK) req->flags |= REQ_F_HARDLINK; INIT_LIST_HEAD(&req->link_list); ret = io_req_defer_prep(req, sqe); if (ret) req->flags |= REQ_F_FAIL_LINK; *link = req; } else { io_queue_sqe(req, sqe); } return true; } /* * Batched submission is done, ensure local IO is flushed out. */ static void io_submit_state_end(struct io_submit_state *state) { blk_finish_plug(&state->plug); io_file_put(state); if (state->free_reqs) kmem_cache_free_bulk(req_cachep, state->free_reqs, &state->reqs[state->cur_req]); } /* * Start submission side cache. */ static void io_submit_state_start(struct io_submit_state *state, unsigned int max_ios) { blk_start_plug(&state->plug); state->free_reqs = 0; state->file = NULL; state->ios_left = max_ios; } static void io_commit_sqring(struct io_ring_ctx *ctx) { struct io_rings *rings = ctx->rings; /* * Ensure any loads from the SQEs are done at this point, * since once we write the new head, the application could * write new data to them. */ smp_store_release(&rings->sq.head, ctx->cached_sq_head); } /* * Fetch an sqe, if one is available. Note that sqe_ptr will point to memory * that is mapped by userspace. This means that care needs to be taken to * ensure that reads are stable, as we cannot rely on userspace always * being a good citizen. If members of the sqe are validated and then later * used, it's important that those reads are done through READ_ONCE() to * prevent a re-load down the line. */ static bool io_get_sqring(struct io_ring_ctx *ctx, struct io_kiocb *req, const struct io_uring_sqe **sqe_ptr) { u32 *sq_array = ctx->sq_array; unsigned head; /* * The cached sq head (or cq tail) serves two purposes: * * 1) allows us to batch the cost of updating the user visible * head updates. * 2) allows the kernel side to track the head on its own, even * though the application is the one updating it. */ head = READ_ONCE(sq_array[ctx->cached_sq_head & ctx->sq_mask]); if (likely(head < ctx->sq_entries)) { /* * All io need record the previous position, if LINK vs DARIN, * it can be used to mark the position of the first IO in the * link list. */ req->sequence = ctx->cached_sq_head; *sqe_ptr = &ctx->sq_sqes[head]; req->opcode = READ_ONCE((*sqe_ptr)->opcode); req->user_data = READ_ONCE((*sqe_ptr)->user_data); ctx->cached_sq_head++; return true; } /* drop invalid entries */ ctx->cached_sq_head++; ctx->cached_sq_dropped++; WRITE_ONCE(ctx->rings->sq_dropped, ctx->cached_sq_dropped); return false; } static int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr, struct file *ring_file, int ring_fd, struct mm_struct **mm, bool async) { struct io_submit_state state, *statep = NULL; struct io_kiocb *link = NULL; int i, submitted = 0; bool mm_fault = false; /* if we have a backlog and couldn't flush it all, return BUSY */ if (test_bit(0, &ctx->sq_check_overflow)) { if (!list_empty(&ctx->cq_overflow_list) && !io_cqring_overflow_flush(ctx, false)) return -EBUSY; } /* make sure SQ entry isn't read before tail */ nr = min3(nr, ctx->sq_entries, io_sqring_entries(ctx)); if (!percpu_ref_tryget_many(&ctx->refs, nr)) return -EAGAIN; if (nr > IO_PLUG_THRESHOLD) { io_submit_state_start(&state, nr); statep = &state; } for (i = 0; i < nr; i++) { const struct io_uring_sqe *sqe; struct io_kiocb *req; req = io_get_req(ctx, statep); if (unlikely(!req)) { if (!submitted) submitted = -EAGAIN; break; } if (!io_get_sqring(ctx, req, &sqe)) { __io_req_do_free(req); break; } /* will complete beyond this point, count as submitted */ submitted++; if (unlikely(req->opcode >= IORING_OP_LAST)) { io_cqring_add_event(req, -EINVAL); io_double_put_req(req); break; } if (io_op_defs[req->opcode].needs_mm && !*mm) { mm_fault = mm_fault || !mmget_not_zero(ctx->sqo_mm); if (!mm_fault) { use_mm(ctx->sqo_mm); *mm = ctx->sqo_mm; } } req->ring_file = ring_file; req->ring_fd = ring_fd; req->has_user = *mm != NULL; req->in_async = async; req->needs_fixed_file = async; trace_io_uring_submit_sqe(ctx, req->user_data, true, async); if (!io_submit_sqe(req, sqe, statep, &link)) break; } if (submitted != nr) percpu_ref_put_many(&ctx->refs, nr - submitted); if (link) io_queue_link_head(link); if (statep) io_submit_state_end(&state); /* Commit SQ ring head once we've consumed and submitted all SQEs */ io_commit_sqring(ctx); return submitted; } static int io_sq_thread(void *data) { struct io_ring_ctx *ctx = data; struct mm_struct *cur_mm = NULL; const struct cred *old_cred; mm_segment_t old_fs; DEFINE_WAIT(wait); unsigned inflight; unsigned long timeout; int ret; complete(&ctx->completions[1]); old_fs = get_fs(); set_fs(USER_DS); old_cred = override_creds(ctx->creds); ret = timeout = inflight = 0; while (!kthread_should_park()) { unsigned int to_submit; if (inflight) { unsigned nr_events = 0; if (ctx->flags & IORING_SETUP_IOPOLL) { /* * inflight is the count of the maximum possible * entries we submitted, but it can be smaller * if we dropped some of them. If we don't have * poll entries available, then we know that we * have nothing left to poll for. Reset the * inflight count to zero in that case. */ mutex_lock(&ctx->uring_lock); if (!list_empty(&ctx->poll_list)) __io_iopoll_check(ctx, &nr_events, 0); else inflight = 0; mutex_unlock(&ctx->uring_lock); } else { /* * Normal IO, just pretend everything completed. * We don't have to poll completions for that. */ nr_events = inflight; } inflight -= nr_events; if (!inflight) timeout = jiffies + ctx->sq_thread_idle; } to_submit = io_sqring_entries(ctx); /* * If submit got -EBUSY, flag us as needing the application * to enter the kernel to reap and flush events. */ if (!to_submit || ret == -EBUSY) { /* * We're polling. If we're within the defined idle * period, then let us spin without work before going * to sleep. The exception is if we got EBUSY doing * more IO, we should wait for the application to * reap events and wake us up. */ if (inflight || (!time_after(jiffies, timeout) && ret != -EBUSY)) { cond_resched(); continue; } /* * Drop cur_mm before scheduling, we can't hold it for * long periods (or over schedule()). Do this before * adding ourselves to the waitqueue, as the unuse/drop * may sleep. */ if (cur_mm) { unuse_mm(cur_mm); mmput(cur_mm); cur_mm = NULL; } prepare_to_wait(&ctx->sqo_wait, &wait, TASK_INTERRUPTIBLE); /* Tell userspace we may need a wakeup call */ ctx->rings->sq_flags |= IORING_SQ_NEED_WAKEUP; /* make sure to read SQ tail after writing flags */ smp_mb(); to_submit = io_sqring_entries(ctx); if (!to_submit || ret == -EBUSY) { if (kthread_should_park()) { finish_wait(&ctx->sqo_wait, &wait); break; } if (signal_pending(current)) flush_signals(current); schedule(); finish_wait(&ctx->sqo_wait, &wait); ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP; continue; } finish_wait(&ctx->sqo_wait, &wait); ctx->rings->sq_flags &= ~IORING_SQ_NEED_WAKEUP; } mutex_lock(&ctx->uring_lock); ret = io_submit_sqes(ctx, to_submit, NULL, -1, &cur_mm, true); mutex_unlock(&ctx->uring_lock); if (ret > 0) inflight += ret; } set_fs(old_fs); if (cur_mm) { unuse_mm(cur_mm); mmput(cur_mm); } revert_creds(old_cred); kthread_parkme(); return 0; } struct io_wait_queue { struct wait_queue_entry wq; struct io_ring_ctx *ctx; unsigned to_wait; unsigned nr_timeouts; }; static inline bool io_should_wake(struct io_wait_queue *iowq, bool noflush) { struct io_ring_ctx *ctx = iowq->ctx; /* * Wake up if we have enough events, or if a timeout occurred since we * started waiting. For timeouts, we always want to return to userspace, * regardless of event count. */ return io_cqring_events(ctx, noflush) >= iowq->to_wait || atomic_read(&ctx->cq_timeouts) != iowq->nr_timeouts; } static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode, int wake_flags, void *key) { struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, wq); /* use noflush == true, as we can't safely rely on locking context */ if (!io_should_wake(iowq, true)) return -1; return autoremove_wake_function(curr, mode, wake_flags, key); } /* * Wait until events become available, if we don't already have some. The * application must reap them itself, as they reside on the shared cq ring. */ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events, const sigset_t __user *sig, size_t sigsz) { struct io_wait_queue iowq = { .wq = { .private = current, .func = io_wake_function, .entry = LIST_HEAD_INIT(iowq.wq.entry), }, .ctx = ctx, .to_wait = min_events, }; struct io_rings *rings = ctx->rings; int ret = 0; if (io_cqring_events(ctx, false) >= min_events) return 0; if (sig) { #ifdef CONFIG_COMPAT if (in_compat_syscall()) ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig, sigsz); else #endif ret = set_user_sigmask(sig, sigsz); if (ret) return ret; } iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts); trace_io_uring_cqring_wait(ctx, min_events); do { prepare_to_wait_exclusive(&ctx->wait, &iowq.wq, TASK_INTERRUPTIBLE); if (io_should_wake(&iowq, false)) break; schedule(); if (signal_pending(current)) { ret = -EINTR; break; } } while (1); finish_wait(&ctx->wait, &iowq.wq); restore_saved_sigmask_unless(ret == -EINTR); return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0; } static void __io_sqe_files_unregister(struct io_ring_ctx *ctx) { #if defined(CONFIG_UNIX) if (ctx->ring_sock) { struct sock *sock = ctx->ring_sock->sk; struct sk_buff *skb; while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL) kfree_skb(skb); } #else int i; for (i = 0; i < ctx->nr_user_files; i++) { struct file *file; file = io_file_from_index(ctx, i); if (file) fput(file); } #endif } static void io_file_ref_kill(struct percpu_ref *ref) { struct fixed_file_data *data; data = container_of(ref, struct fixed_file_data, refs); complete(&data->done); } static int io_sqe_files_unregister(struct io_ring_ctx *ctx) { struct fixed_file_data *data = ctx->file_data; unsigned nr_tables, i; if (!data) return -ENXIO; /* protect against inflight atomic switch, which drops the ref */ flush_work(&data->ref_work); percpu_ref_get(&data->refs); percpu_ref_kill_and_confirm(&data->refs, io_file_ref_kill); wait_for_completion(&data->done); percpu_ref_put(&data->refs); percpu_ref_exit(&data->refs); __io_sqe_files_unregister(ctx); nr_tables = DIV_ROUND_UP(ctx->nr_user_files, IORING_MAX_FILES_TABLE); for (i = 0; i < nr_tables; i++) kfree(data->table[i].files); kfree(data->table); kfree(data); ctx->file_data = NULL; ctx->nr_user_files = 0; return 0; } static void io_sq_thread_stop(struct io_ring_ctx *ctx) { if (ctx->sqo_thread) { wait_for_completion(&ctx->completions[1]); /* * The park is a bit of a work-around, without it we get * warning spews on shutdown with SQPOLL set and affinity * set to a single CPU. */ kthread_park(ctx->sqo_thread); kthread_stop(ctx->sqo_thread); ctx->sqo_thread = NULL; } } static void io_finish_async(struct io_ring_ctx *ctx) { io_sq_thread_stop(ctx); if (ctx->io_wq) { io_wq_destroy(ctx->io_wq); ctx->io_wq = NULL; } } #if defined(CONFIG_UNIX) /* * Ensure the UNIX gc is aware of our file set, so we are certain that * the io_uring can be safely unregistered on process exit, even if we have * loops in the file referencing. */ static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset) { struct sock *sk = ctx->ring_sock->sk; struct scm_fp_list *fpl; struct sk_buff *skb; int i, nr_files; if (!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) { unsigned long inflight = ctx->user->unix_inflight + nr; if (inflight > task_rlimit(current, RLIMIT_NOFILE)) return -EMFILE; } fpl = kzalloc(sizeof(*fpl), GFP_KERNEL); if (!fpl) return -ENOMEM; skb = alloc_skb(0, GFP_KERNEL); if (!skb) { kfree(fpl); return -ENOMEM; } skb->sk = sk; nr_files = 0; fpl->user = get_uid(ctx->user); for (i = 0; i < nr; i++) { struct file *file = io_file_from_index(ctx, i + offset); if (!file) continue; fpl->fp[nr_files] = get_file(file); unix_inflight(fpl->user, fpl->fp[nr_files]); nr_files++; } if (nr_files) { fpl->max = SCM_MAX_FD; fpl->count = nr_files; UNIXCB(skb).fp = fpl; skb->destructor = unix_destruct_scm; refcount_add(skb->truesize, &sk->sk_wmem_alloc); skb_queue_head(&sk->sk_receive_queue, skb); for (i = 0; i < nr_files; i++) fput(fpl->fp[i]); } else { kfree_skb(skb); kfree(fpl); } return 0; } /* * If UNIX sockets are enabled, fd passing can cause a reference cycle which * causes regular reference counting to break down. We rely on the UNIX * garbage collection to take care of this problem for us. */ static int io_sqe_files_scm(struct io_ring_ctx *ctx) { unsigned left, total; int ret = 0; total = 0; left = ctx->nr_user_files; while (left) { unsigned this_files = min_t(unsigned, left, SCM_MAX_FD); ret = __io_sqe_files_scm(ctx, this_files, total); if (ret) break; left -= this_files; total += this_files; } if (!ret) return 0; while (total < ctx->nr_user_files) { struct file *file = io_file_from_index(ctx, total); if (file) fput(file); total++; } return ret; } #else static int io_sqe_files_scm(struct io_ring_ctx *ctx) { return 0; } #endif static int io_sqe_alloc_file_tables(struct io_ring_ctx *ctx, unsigned nr_tables, unsigned nr_files) { int i; for (i = 0; i < nr_tables; i++) { struct fixed_file_table *table = &ctx->file_data->table[i]; unsigned this_files; this_files = min(nr_files, IORING_MAX_FILES_TABLE); table->files = kcalloc(this_files, sizeof(struct file *), GFP_KERNEL); if (!table->files) break; nr_files -= this_files; } if (i == nr_tables) return 0; for (i = 0; i < nr_tables; i++) { struct fixed_file_table *table = &ctx->file_data->table[i]; kfree(table->files); } return 1; } static void io_ring_file_put(struct io_ring_ctx *ctx, struct file *file) { #if defined(CONFIG_UNIX) struct sock *sock = ctx->ring_sock->sk; struct sk_buff_head list, *head = &sock->sk_receive_queue; struct sk_buff *skb; int i; __skb_queue_head_init(&list); /* * Find the skb that holds this file in its SCM_RIGHTS. When found, * remove this entry and rearrange the file array. */ skb = skb_dequeue(head); while (skb) { struct scm_fp_list *fp; fp = UNIXCB(skb).fp; for (i = 0; i < fp->count; i++) { int left; if (fp->fp[i] != file) continue; unix_notinflight(fp->user, fp->fp[i]); left = fp->count - 1 - i; if (left) { memmove(&fp->fp[i], &fp->fp[i + 1], left * sizeof(struct file *)); } fp->count--; if (!fp->count) { kfree_skb(skb); skb = NULL; } else { __skb_queue_tail(&list, skb); } fput(file); file = NULL; break; } if (!file) break; __skb_queue_tail(&list, skb); skb = skb_dequeue(head); } if (skb_peek(&list)) { spin_lock_irq(&head->lock); while ((skb = __skb_dequeue(&list)) != NULL) __skb_queue_tail(head, skb); spin_unlock_irq(&head->lock); } #else fput(file); #endif } struct io_file_put { struct llist_node llist; struct file *file; struct completion *done; }; static void io_ring_file_ref_switch(struct work_struct *work) { struct io_file_put *pfile, *tmp; struct fixed_file_data *data; struct llist_node *node; data = container_of(work, struct fixed_file_data, ref_work); while ((node = llist_del_all(&data->put_llist)) != NULL) { llist_for_each_entry_safe(pfile, tmp, node, llist) { io_ring_file_put(data->ctx, pfile->file); if (pfile->done) complete(pfile->done); else kfree(pfile); } } percpu_ref_get(&data->refs); percpu_ref_switch_to_percpu(&data->refs); } static void io_file_data_ref_zero(struct percpu_ref *ref) { struct fixed_file_data *data; data = container_of(ref, struct fixed_file_data, refs); /* we can't safely switch from inside this context, punt to wq */ queue_work(system_wq, &data->ref_work); } static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { __s32 __user *fds = (__s32 __user *) arg; unsigned nr_tables; struct file *file; int fd, ret = 0; unsigned i; if (ctx->file_data) return -EBUSY; if (!nr_args) return -EINVAL; if (nr_args > IORING_MAX_FIXED_FILES) return -EMFILE; ctx->file_data = kzalloc(sizeof(*ctx->file_data), GFP_KERNEL); if (!ctx->file_data) return -ENOMEM; ctx->file_data->ctx = ctx; init_completion(&ctx->file_data->done); nr_tables = DIV_ROUND_UP(nr_args, IORING_MAX_FILES_TABLE); ctx->file_data->table = kcalloc(nr_tables, sizeof(struct fixed_file_table), GFP_KERNEL); if (!ctx->file_data->table) { kfree(ctx->file_data); ctx->file_data = NULL; return -ENOMEM; } if (percpu_ref_init(&ctx->file_data->refs, io_file_data_ref_zero, PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) { kfree(ctx->file_data->table); kfree(ctx->file_data); ctx->file_data = NULL; return -ENOMEM; } ctx->file_data->put_llist.first = NULL; INIT_WORK(&ctx->file_data->ref_work, io_ring_file_ref_switch); if (io_sqe_alloc_file_tables(ctx, nr_tables, nr_args)) { percpu_ref_exit(&ctx->file_data->refs); kfree(ctx->file_data->table); kfree(ctx->file_data); ctx->file_data = NULL; return -ENOMEM; } for (i = 0; i < nr_args; i++, ctx->nr_user_files++) { struct fixed_file_table *table; unsigned index; ret = -EFAULT; if (copy_from_user(&fd, &fds[i], sizeof(fd))) break; /* allow sparse sets */ if (fd == -1) { ret = 0; continue; } table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT]; index = i & IORING_FILE_TABLE_MASK; file = fget(fd); ret = -EBADF; if (!file) break; /* * Don't allow io_uring instances to be registered. If UNIX * isn't enabled, then this causes a reference cycle and this * instance can never get freed. If UNIX is enabled we'll * handle it just fine, but there's still no point in allowing * a ring fd as it doesn't support regular read/write anyway. */ if (file->f_op == &io_uring_fops) { fput(file); break; } ret = 0; table->files[index] = file; } if (ret) { for (i = 0; i < ctx->nr_user_files; i++) { file = io_file_from_index(ctx, i); if (file) fput(file); } for (i = 0; i < nr_tables; i++) kfree(ctx->file_data->table[i].files); kfree(ctx->file_data->table); kfree(ctx->file_data); ctx->file_data = NULL; ctx->nr_user_files = 0; return ret; } ret = io_sqe_files_scm(ctx); if (ret) io_sqe_files_unregister(ctx); return ret; } static int io_sqe_file_register(struct io_ring_ctx *ctx, struct file *file, int index) { #if defined(CONFIG_UNIX) struct sock *sock = ctx->ring_sock->sk; struct sk_buff_head *head = &sock->sk_receive_queue; struct sk_buff *skb; /* * See if we can merge this file into an existing skb SCM_RIGHTS * file set. If there's no room, fall back to allocating a new skb * and filling it in. */ spin_lock_irq(&head->lock); skb = skb_peek(head); if (skb) { struct scm_fp_list *fpl = UNIXCB(skb).fp; if (fpl->count < SCM_MAX_FD) { __skb_unlink(skb, head); spin_unlock_irq(&head->lock); fpl->fp[fpl->count] = get_file(file); unix_inflight(fpl->user, fpl->fp[fpl->count]); fpl->count++; spin_lock_irq(&head->lock); __skb_queue_head(head, skb); } else { skb = NULL; } } spin_unlock_irq(&head->lock); if (skb) { fput(file); return 0; } return __io_sqe_files_scm(ctx, 1, index); #else return 0; #endif } static void io_atomic_switch(struct percpu_ref *ref) { struct fixed_file_data *data; data = container_of(ref, struct fixed_file_data, refs); clear_bit(FFD_F_ATOMIC, &data->state); } static bool io_queue_file_removal(struct fixed_file_data *data, struct file *file) { struct io_file_put *pfile, pfile_stack; DECLARE_COMPLETION_ONSTACK(done); /* * If we fail allocating the struct we need for doing async reomval * of this file, just punt to sync and wait for it. */ pfile = kzalloc(sizeof(*pfile), GFP_KERNEL); if (!pfile) { pfile = &pfile_stack; pfile->done = &done; } pfile->file = file; llist_add(&pfile->llist, &data->put_llist); if (pfile == &pfile_stack) { if (!test_and_set_bit(FFD_F_ATOMIC, &data->state)) { percpu_ref_put(&data->refs); percpu_ref_switch_to_atomic(&data->refs, io_atomic_switch); } wait_for_completion(&done); flush_work(&data->ref_work); return false; } return true; } static int __io_sqe_files_update(struct io_ring_ctx *ctx, struct io_uring_files_update *up, unsigned nr_args) { struct fixed_file_data *data = ctx->file_data; bool ref_switch = false; struct file *file; __s32 __user *fds; int fd, i, err; __u32 done; if (check_add_overflow(up->offset, nr_args, &done)) return -EOVERFLOW; if (done > ctx->nr_user_files) return -EINVAL; done = 0; fds = u64_to_user_ptr(up->fds); while (nr_args) { struct fixed_file_table *table; unsigned index; err = 0; if (copy_from_user(&fd, &fds[done], sizeof(fd))) { err = -EFAULT; break; } i = array_index_nospec(up->offset, ctx->nr_user_files); table = &ctx->file_data->table[i >> IORING_FILE_TABLE_SHIFT]; index = i & IORING_FILE_TABLE_MASK; if (table->files[index]) { file = io_file_from_index(ctx, index); table->files[index] = NULL; if (io_queue_file_removal(data, file)) ref_switch = true; } if (fd != -1) { file = fget(fd); if (!file) { err = -EBADF; break; } /* * Don't allow io_uring instances to be registered. If * UNIX isn't enabled, then this causes a reference * cycle and this instance can never get freed. If UNIX * is enabled we'll handle it just fine, but there's * still no point in allowing a ring fd as it doesn't * support regular read/write anyway. */ if (file->f_op == &io_uring_fops) { fput(file); err = -EBADF; break; } table->files[index] = file; err = io_sqe_file_register(ctx, file, i); if (err) break; } nr_args--; done++; up->offset++; } if (ref_switch && !test_and_set_bit(FFD_F_ATOMIC, &data->state)) { percpu_ref_put(&data->refs); percpu_ref_switch_to_atomic(&data->refs, io_atomic_switch); } return done ? done : err; } static int io_sqe_files_update(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { struct io_uring_files_update up; if (!ctx->file_data) return -ENXIO; if (!nr_args) return -EINVAL; if (copy_from_user(&up, arg, sizeof(up))) return -EFAULT; if (up.resv) return -EINVAL; return __io_sqe_files_update(ctx, &up, nr_args); } static void io_put_work(struct io_wq_work *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); io_put_req(req); } static void io_get_work(struct io_wq_work *work) { struct io_kiocb *req = container_of(work, struct io_kiocb, work); refcount_inc(&req->refs); } static int io_sq_offload_start(struct io_ring_ctx *ctx, struct io_uring_params *p) { struct io_wq_data data; unsigned concurrency; int ret; init_waitqueue_head(&ctx->sqo_wait); mmgrab(current->mm); ctx->sqo_mm = current->mm; if (ctx->flags & IORING_SETUP_SQPOLL) { ret = -EPERM; if (!capable(CAP_SYS_ADMIN)) goto err; ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle); if (!ctx->sq_thread_idle) ctx->sq_thread_idle = HZ; if (p->flags & IORING_SETUP_SQ_AFF) { int cpu = p->sq_thread_cpu; ret = -EINVAL; if (cpu >= nr_cpu_ids) goto err; if (!cpu_online(cpu)) goto err; ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread, ctx, cpu, "io_uring-sq"); } else { ctx->sqo_thread = kthread_create(io_sq_thread, ctx, "io_uring-sq"); } if (IS_ERR(ctx->sqo_thread)) { ret = PTR_ERR(ctx->sqo_thread); ctx->sqo_thread = NULL; goto err; } wake_up_process(ctx->sqo_thread); } else if (p->flags & IORING_SETUP_SQ_AFF) { /* Can't have SQ_AFF without SQPOLL */ ret = -EINVAL; goto err; } data.mm = ctx->sqo_mm; data.user = ctx->user; data.creds = ctx->creds; data.get_work = io_get_work; data.put_work = io_put_work; /* Do QD, or 4 * CPUS, whatever is smallest */ concurrency = min(ctx->sq_entries, 4 * num_online_cpus()); ctx->io_wq = io_wq_create(concurrency, &data); if (IS_ERR(ctx->io_wq)) { ret = PTR_ERR(ctx->io_wq); ctx->io_wq = NULL; goto err; } return 0; err: io_finish_async(ctx); mmdrop(ctx->sqo_mm); ctx->sqo_mm = NULL; return ret; } static void io_unaccount_mem(struct user_struct *user, unsigned long nr_pages) { atomic_long_sub(nr_pages, &user->locked_vm); } static int io_account_mem(struct user_struct *user, unsigned long nr_pages) { unsigned long page_limit, cur_pages, new_pages; /* Don't allow more pages than we can safely lock */ page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; do { cur_pages = atomic_long_read(&user->locked_vm); new_pages = cur_pages + nr_pages; if (new_pages > page_limit) return -ENOMEM; } while (atomic_long_cmpxchg(&user->locked_vm, cur_pages, new_pages) != cur_pages); return 0; } static void io_mem_free(void *ptr) { struct page *page; if (!ptr) return; page = virt_to_head_page(ptr); if (put_page_testzero(page)) free_compound_page(page); } static void *io_mem_alloc(size_t size) { gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP | __GFP_NORETRY; return (void *) __get_free_pages(gfp_flags, get_order(size)); } static unsigned long rings_size(unsigned sq_entries, unsigned cq_entries, size_t *sq_offset) { struct io_rings *rings; size_t off, sq_array_size; off = struct_size(rings, cqes, cq_entries); if (off == SIZE_MAX) return SIZE_MAX; #ifdef CONFIG_SMP off = ALIGN(off, SMP_CACHE_BYTES); if (off == 0) return SIZE_MAX; #endif sq_array_size = array_size(sizeof(u32), sq_entries); if (sq_array_size == SIZE_MAX) return SIZE_MAX; if (check_add_overflow(off, sq_array_size, &off)) return SIZE_MAX; if (sq_offset) *sq_offset = off; return off; } static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries) { size_t pages; pages = (size_t)1 << get_order( rings_size(sq_entries, cq_entries, NULL)); pages += (size_t)1 << get_order( array_size(sizeof(struct io_uring_sqe), sq_entries)); return pages; } static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx) { int i, j; if (!ctx->user_bufs) return -ENXIO; for (i = 0; i < ctx->nr_user_bufs; i++) { struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; for (j = 0; j < imu->nr_bvecs; j++) put_user_page(imu->bvec[j].bv_page); if (ctx->account_mem) io_unaccount_mem(ctx->user, imu->nr_bvecs); kvfree(imu->bvec); imu->nr_bvecs = 0; } kfree(ctx->user_bufs); ctx->user_bufs = NULL; ctx->nr_user_bufs = 0; return 0; } static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst, void __user *arg, unsigned index) { struct iovec __user *src; #ifdef CONFIG_COMPAT if (ctx->compat) { struct compat_iovec __user *ciovs; struct compat_iovec ciov; ciovs = (struct compat_iovec __user *) arg; if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov))) return -EFAULT; dst->iov_base = u64_to_user_ptr((u64)ciov.iov_base); dst->iov_len = ciov.iov_len; return 0; } #endif src = (struct iovec __user *) arg; if (copy_from_user(dst, &src[index], sizeof(*dst))) return -EFAULT; return 0; } static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg, unsigned nr_args) { struct vm_area_struct **vmas = NULL; struct page **pages = NULL; int i, j, got_pages = 0; int ret = -EINVAL; if (ctx->user_bufs) return -EBUSY; if (!nr_args || nr_args > UIO_MAXIOV) return -EINVAL; ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf), GFP_KERNEL); if (!ctx->user_bufs) return -ENOMEM; for (i = 0; i < nr_args; i++) { struct io_mapped_ubuf *imu = &ctx->user_bufs[i]; unsigned long off, start, end, ubuf; int pret, nr_pages; struct iovec iov; size_t size; ret = io_copy_iov(ctx, &iov, arg, i); if (ret) goto err; /* * Don't impose further limits on the size and buffer * constraints here, we'll -EINVAL later when IO is * submitted if they are wrong. */ ret = -EFAULT; if (!iov.iov_base || !iov.iov_len) goto err; /* arbitrary limit, but we need something */ if (iov.iov_len > SZ_1G) goto err; ubuf = (unsigned long) iov.iov_base; end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT; start = ubuf >> PAGE_SHIFT; nr_pages = end - start; if (ctx->account_mem) { ret = io_account_mem(ctx->user, nr_pages); if (ret) goto err; } ret = 0; if (!pages || nr_pages > got_pages) { kfree(vmas); kfree(pages); pages = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL); vmas = kvmalloc_array(nr_pages, sizeof(struct vm_area_struct *), GFP_KERNEL); if (!pages || !vmas) { ret = -ENOMEM; if (ctx->account_mem) io_unaccount_mem(ctx->user, nr_pages); goto err; } got_pages = nr_pages; } imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec), GFP_KERNEL); ret = -ENOMEM; if (!imu->bvec) { if (ctx->account_mem) io_unaccount_mem(ctx->user, nr_pages); goto err; } ret = 0; down_read(¤t->mm->mmap_sem); pret = get_user_pages(ubuf, nr_pages, FOLL_WRITE | FOLL_LONGTERM, pages, vmas); if (pret == nr_pages) { /* don't support file backed memory */ for (j = 0; j < nr_pages; j++) { struct vm_area_struct *vma = vmas[j]; if (vma->vm_file && !is_file_hugepages(vma->vm_file)) { ret = -EOPNOTSUPP; break; } } } else { ret = pret < 0 ? pret : -EFAULT; } up_read(¤t->mm->mmap_sem); if (ret) { /* * if we did partial map, or found file backed vmas, * release any pages we did get */ if (pret > 0) put_user_pages(pages, pret); if (ctx->account_mem) io_unaccount_mem(ctx->user, nr_pages); kvfree(imu->bvec); goto err; } off = ubuf & ~PAGE_MASK; size = iov.iov_len; for (j = 0; j < nr_pages; j++) { size_t vec_len; vec_len = min_t(size_t, size, PAGE_SIZE - off); imu->bvec[j].bv_page = pages[j]; imu->bvec[j].bv_len = vec_len; imu->bvec[j].bv_offset = off; off = 0; size -= vec_len; } /* store original address for later verification */ imu->ubuf = ubuf; imu->len = iov.iov_len; imu->nr_bvecs = nr_pages; ctx->nr_user_bufs++; } kvfree(pages); kvfree(vmas); return 0; err: kvfree(pages); kvfree(vmas); io_sqe_buffer_unregister(ctx); return ret; } static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg) { __s32 __user *fds = arg; int fd; if (ctx->cq_ev_fd) return -EBUSY; if (copy_from_user(&fd, fds, sizeof(*fds))) return -EFAULT; ctx->cq_ev_fd = eventfd_ctx_fdget(fd); if (IS_ERR(ctx->cq_ev_fd)) { int ret = PTR_ERR(ctx->cq_ev_fd); ctx->cq_ev_fd = NULL; return ret; } return 0; } static int io_eventfd_unregister(struct io_ring_ctx *ctx) { if (ctx->cq_ev_fd) { eventfd_ctx_put(ctx->cq_ev_fd); ctx->cq_ev_fd = NULL; return 0; } return -ENXIO; } static void io_ring_ctx_free(struct io_ring_ctx *ctx) { io_finish_async(ctx); if (ctx->sqo_mm) mmdrop(ctx->sqo_mm); io_iopoll_reap_events(ctx); io_sqe_buffer_unregister(ctx); io_sqe_files_unregister(ctx); io_eventfd_unregister(ctx); #if defined(CONFIG_UNIX) if (ctx->ring_sock) { ctx->ring_sock->file = NULL; /* so that iput() is called */ sock_release(ctx->ring_sock); } #endif io_mem_free(ctx->rings); io_mem_free(ctx->sq_sqes); percpu_ref_exit(&ctx->refs); if (ctx->account_mem) io_unaccount_mem(ctx->user, ring_pages(ctx->sq_entries, ctx->cq_entries)); free_uid(ctx->user); put_cred(ctx->creds); kfree(ctx->completions); kfree(ctx->cancel_hash); kmem_cache_free(req_cachep, ctx->fallback_req); kfree(ctx); } static __poll_t io_uring_poll(struct file *file, poll_table *wait) { struct io_ring_ctx *ctx = file->private_data; __poll_t mask = 0; poll_wait(file, &ctx->cq_wait, wait); /* * synchronizes with barrier from wq_has_sleeper call in * io_commit_cqring */ smp_rmb(); if (READ_ONCE(ctx->rings->sq.tail) - ctx->cached_sq_head != ctx->rings->sq_ring_entries) mask |= EPOLLOUT | EPOLLWRNORM; if (READ_ONCE(ctx->rings->cq.head) != ctx->cached_cq_tail) mask |= EPOLLIN | EPOLLRDNORM; return mask; } static int io_uring_fasync(int fd, struct file *file, int on) { struct io_ring_ctx *ctx = file->private_data; return fasync_helper(fd, file, on, &ctx->cq_fasync); } static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx) { mutex_lock(&ctx->uring_lock); percpu_ref_kill(&ctx->refs); mutex_unlock(&ctx->uring_lock); io_kill_timeouts(ctx); io_poll_remove_all(ctx); if (ctx->io_wq) io_wq_cancel_all(ctx->io_wq); io_iopoll_reap_events(ctx); /* if we failed setting up the ctx, we might not have any rings */ if (ctx->rings) io_cqring_overflow_flush(ctx, true); wait_for_completion(&ctx->completions[0]); io_ring_ctx_free(ctx); } static int io_uring_release(struct inode *inode, struct file *file) { struct io_ring_ctx *ctx = file->private_data; file->private_data = NULL; io_ring_ctx_wait_and_kill(ctx); return 0; } static void io_uring_cancel_files(struct io_ring_ctx *ctx, struct files_struct *files) { struct io_kiocb *req; DEFINE_WAIT(wait); while (!list_empty_careful(&ctx->inflight_list)) { struct io_kiocb *cancel_req = NULL; spin_lock_irq(&ctx->inflight_lock); list_for_each_entry(req, &ctx->inflight_list, inflight_entry) { if (req->work.files != files) continue; /* req is being completed, ignore */ if (!refcount_inc_not_zero(&req->refs)) continue; cancel_req = req; break; } if (cancel_req) prepare_to_wait(&ctx->inflight_wait, &wait, TASK_UNINTERRUPTIBLE); spin_unlock_irq(&ctx->inflight_lock); /* We need to keep going until we don't find a matching req */ if (!cancel_req) break; io_wq_cancel_work(ctx->io_wq, &cancel_req->work); io_put_req(cancel_req); schedule(); } finish_wait(&ctx->inflight_wait, &wait); } static int io_uring_flush(struct file *file, void *data) { struct io_ring_ctx *ctx = file->private_data; io_uring_cancel_files(ctx, data); if (fatal_signal_pending(current) || (current->flags & PF_EXITING)) { io_cqring_overflow_flush(ctx, true); io_wq_cancel_all(ctx->io_wq); } return 0; } static void *io_uring_validate_mmap_request(struct file *file, loff_t pgoff, size_t sz) { struct io_ring_ctx *ctx = file->private_data; loff_t offset = pgoff << PAGE_SHIFT; struct page *page; void *ptr; switch (offset) { case IORING_OFF_SQ_RING: case IORING_OFF_CQ_RING: ptr = ctx->rings; break; case IORING_OFF_SQES: ptr = ctx->sq_sqes; break; default: return ERR_PTR(-EINVAL); } page = virt_to_head_page(ptr); if (sz > page_size(page)) return ERR_PTR(-EINVAL); return ptr; } #ifdef CONFIG_MMU static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) { size_t sz = vma->vm_end - vma->vm_start; unsigned long pfn; void *ptr; ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz); if (IS_ERR(ptr)) return PTR_ERR(ptr); pfn = virt_to_phys(ptr) >> PAGE_SHIFT; return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); } #else /* !CONFIG_MMU */ static int io_uring_mmap(struct file *file, struct vm_area_struct *vma) { return vma->vm_flags & (VM_SHARED | VM_MAYSHARE) ? 0 : -EINVAL; } static unsigned int io_uring_nommu_mmap_capabilities(struct file *file) { return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE; } static unsigned long io_uring_nommu_get_unmapped_area(struct file *file, unsigned long addr, unsigned long len, unsigned long pgoff, unsigned long flags) { void *ptr; ptr = io_uring_validate_mmap_request(file, pgoff, len); if (IS_ERR(ptr)) return PTR_ERR(ptr); return (unsigned long) ptr; } #endif /* !CONFIG_MMU */ SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit, u32, min_complete, u32, flags, const sigset_t __user *, sig, size_t, sigsz) { struct io_ring_ctx *ctx; long ret = -EBADF; int submitted = 0; struct fd f; if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP)) return -EINVAL; f = fdget(fd); if (!f.file) return -EBADF; ret = -EOPNOTSUPP; if (f.file->f_op != &io_uring_fops) goto out_fput; ret = -ENXIO; ctx = f.file->private_data; if (!percpu_ref_tryget(&ctx->refs)) goto out_fput; /* * For SQ polling, the thread will do all submissions and completions. * Just return the requested submit count, and wake the thread if * we were asked to. */ ret = 0; if (ctx->flags & IORING_SETUP_SQPOLL) { if (!list_empty_careful(&ctx->cq_overflow_list)) io_cqring_overflow_flush(ctx, false); if (flags & IORING_ENTER_SQ_WAKEUP) wake_up(&ctx->sqo_wait); submitted = to_submit; } else if (to_submit) { struct mm_struct *cur_mm; if (current->mm != ctx->sqo_mm || current_cred() != ctx->creds) { ret = -EPERM; goto out; } mutex_lock(&ctx->uring_lock); /* already have mm, so io_submit_sqes() won't try to grab it */ cur_mm = ctx->sqo_mm; submitted = io_submit_sqes(ctx, to_submit, f.file, fd, &cur_mm, false); mutex_unlock(&ctx->uring_lock); if (submitted != to_submit) goto out; } if (flags & IORING_ENTER_GETEVENTS) { unsigned nr_events = 0; min_complete = min(min_complete, ctx->cq_entries); if (ctx->flags & IORING_SETUP_IOPOLL) { ret = io_iopoll_check(ctx, &nr_events, min_complete); } else { ret = io_cqring_wait(ctx, min_complete, sig, sigsz); } } out: percpu_ref_put(&ctx->refs); out_fput: fdput(f); return submitted ? submitted : ret; } static const struct file_operations io_uring_fops = { .release = io_uring_release, .flush = io_uring_flush, .mmap = io_uring_mmap, #ifndef CONFIG_MMU .get_unmapped_area = io_uring_nommu_get_unmapped_area, .mmap_capabilities = io_uring_nommu_mmap_capabilities, #endif .poll = io_uring_poll, .fasync = io_uring_fasync, }; static int io_allocate_scq_urings(struct io_ring_ctx *ctx, struct io_uring_params *p) { struct io_rings *rings; size_t size, sq_array_offset; size = rings_size(p->sq_entries, p->cq_entries, &sq_array_offset); if (size == SIZE_MAX) return -EOVERFLOW; rings = io_mem_alloc(size); if (!rings) return -ENOMEM; ctx->rings = rings; ctx->sq_array = (u32 *)((char *)rings + sq_array_offset); rings->sq_ring_mask = p->sq_entries - 1; rings->cq_ring_mask = p->cq_entries - 1; rings->sq_ring_entries = p->sq_entries; rings->cq_ring_entries = p->cq_entries; ctx->sq_mask = rings->sq_ring_mask; ctx->cq_mask = rings->cq_ring_mask; ctx->sq_entries = rings->sq_ring_entries; ctx->cq_entries = rings->cq_ring_entries; size = array_size(sizeof(struct io_uring_sqe), p->sq_entries); if (size == SIZE_MAX) { io_mem_free(ctx->rings); ctx->rings = NULL; return -EOVERFLOW; } ctx->sq_sqes = io_mem_alloc(size); if (!ctx->sq_sqes) { io_mem_free(ctx->rings); ctx->rings = NULL; return -ENOMEM; } return 0; } /* * Allocate an anonymous fd, this is what constitutes the application * visible backing of an io_uring instance. The application mmaps this * fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled, * we have to tie this fd to a socket for file garbage collection purposes. */ static int io_uring_get_fd(struct io_ring_ctx *ctx) { struct file *file; int ret; #if defined(CONFIG_UNIX) ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP, &ctx->ring_sock); if (ret) return ret; #endif ret = get_unused_fd_flags(O_RDWR | O_CLOEXEC); if (ret < 0) goto err; file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx, O_RDWR | O_CLOEXEC); if (IS_ERR(file)) { put_unused_fd(ret); ret = PTR_ERR(file); goto err; } #if defined(CONFIG_UNIX) ctx->ring_sock->file = file; #endif fd_install(ret, file); return ret; err: #if defined(CONFIG_UNIX) sock_release(ctx->ring_sock); ctx->ring_sock = NULL; #endif return ret; } static int io_uring_create(unsigned entries, struct io_uring_params *p) { struct user_struct *user = NULL; struct io_ring_ctx *ctx; bool account_mem; int ret; if (!entries) return -EINVAL; if (entries > IORING_MAX_ENTRIES) { if (!(p->flags & IORING_SETUP_CLAMP)) return -EINVAL; entries = IORING_MAX_ENTRIES; } /* * Use twice as many entries for the CQ ring. It's possible for the * application to drive a higher depth than the size of the SQ ring, * since the sqes are only used at submission time. This allows for * some flexibility in overcommitting a bit. If the application has * set IORING_SETUP_CQSIZE, it will have passed in the desired number * of CQ ring entries manually. */ p->sq_entries = roundup_pow_of_two(entries); if (p->flags & IORING_SETUP_CQSIZE) { /* * If IORING_SETUP_CQSIZE is set, we do the same roundup * to a power-of-two, if it isn't already. We do NOT impose * any cq vs sq ring sizing. */ if (p->cq_entries < p->sq_entries) return -EINVAL; if (p->cq_entries > IORING_MAX_CQ_ENTRIES) { if (!(p->flags & IORING_SETUP_CLAMP)) return -EINVAL; p->cq_entries = IORING_MAX_CQ_ENTRIES; } p->cq_entries = roundup_pow_of_two(p->cq_entries); } else { p->cq_entries = 2 * p->sq_entries; } user = get_uid(current_user()); account_mem = !capable(CAP_IPC_LOCK); if (account_mem) { ret = io_account_mem(user, ring_pages(p->sq_entries, p->cq_entries)); if (ret) { free_uid(user); return ret; } } ctx = io_ring_ctx_alloc(p); if (!ctx) { if (account_mem) io_unaccount_mem(user, ring_pages(p->sq_entries, p->cq_entries)); free_uid(user); return -ENOMEM; } ctx->compat = in_compat_syscall(); ctx->account_mem = account_mem; ctx->user = user; ctx->creds = get_current_cred(); ret = io_allocate_scq_urings(ctx, p); if (ret) goto err; ret = io_sq_offload_start(ctx, p); if (ret) goto err; memset(&p->sq_off, 0, sizeof(p->sq_off)); p->sq_off.head = offsetof(struct io_rings, sq.head); p->sq_off.tail = offsetof(struct io_rings, sq.tail); p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask); p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries); p->sq_off.flags = offsetof(struct io_rings, sq_flags); p->sq_off.dropped = offsetof(struct io_rings, sq_dropped); p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings; memset(&p->cq_off, 0, sizeof(p->cq_off)); p->cq_off.head = offsetof(struct io_rings, cq.head); p->cq_off.tail = offsetof(struct io_rings, cq.tail); p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask); p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries); p->cq_off.overflow = offsetof(struct io_rings, cq_overflow); p->cq_off.cqes = offsetof(struct io_rings, cqes); /* * Install ring fd as the very last thing, so we don't risk someone * having closed it before we finish setup */ ret = io_uring_get_fd(ctx); if (ret < 0) goto err; p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP | IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS; trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags); return ret; err: io_ring_ctx_wait_and_kill(ctx); return ret; } /* * Sets up an aio uring context, and returns the fd. Applications asks for a * ring size, we return the actual sq/cq ring sizes (among other things) in the * params structure passed in. */ static long io_uring_setup(u32 entries, struct io_uring_params __user *params) { struct io_uring_params p; long ret; int i; if (copy_from_user(&p, params, sizeof(p))) return -EFAULT; for (i = 0; i < ARRAY_SIZE(p.resv); i++) { if (p.resv[i]) return -EINVAL; } if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL | IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE | IORING_SETUP_CLAMP)) return -EINVAL; ret = io_uring_create(entries, &p); if (ret < 0) return ret; if (copy_to_user(params, &p, sizeof(p))) return -EFAULT; return ret; } SYSCALL_DEFINE2(io_uring_setup, u32, entries, struct io_uring_params __user *, params) { return io_uring_setup(entries, params); } static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode, void __user *arg, unsigned nr_args) __releases(ctx->uring_lock) __acquires(ctx->uring_lock) { int ret; /* * We're inside the ring mutex, if the ref is already dying, then * someone else killed the ctx or is already going through * io_uring_register(). */ if (percpu_ref_is_dying(&ctx->refs)) return -ENXIO; if (opcode != IORING_UNREGISTER_FILES && opcode != IORING_REGISTER_FILES_UPDATE) { percpu_ref_kill(&ctx->refs); /* * Drop uring mutex before waiting for references to exit. If * another thread is currently inside io_uring_enter() it might * need to grab the uring_lock to make progress. If we hold it * here across the drain wait, then we can deadlock. It's safe * to drop the mutex here, since no new references will come in * after we've killed the percpu ref. */ mutex_unlock(&ctx->uring_lock); wait_for_completion(&ctx->completions[0]); mutex_lock(&ctx->uring_lock); } switch (opcode) { case IORING_REGISTER_BUFFERS: ret = io_sqe_buffer_register(ctx, arg, nr_args); break; case IORING_UNREGISTER_BUFFERS: ret = -EINVAL; if (arg || nr_args) break; ret = io_sqe_buffer_unregister(ctx); break; case IORING_REGISTER_FILES: ret = io_sqe_files_register(ctx, arg, nr_args); break; case IORING_UNREGISTER_FILES: ret = -EINVAL; if (arg || nr_args) break; ret = io_sqe_files_unregister(ctx); break; case IORING_REGISTER_FILES_UPDATE: ret = io_sqe_files_update(ctx, arg, nr_args); break; case IORING_REGISTER_EVENTFD: ret = -EINVAL; if (nr_args != 1) break; ret = io_eventfd_register(ctx, arg); break; case IORING_UNREGISTER_EVENTFD: ret = -EINVAL; if (arg || nr_args) break; ret = io_eventfd_unregister(ctx); break; default: ret = -EINVAL; break; } if (opcode != IORING_UNREGISTER_FILES && opcode != IORING_REGISTER_FILES_UPDATE) { /* bring the ctx back to life */ reinit_completion(&ctx->completions[0]); percpu_ref_reinit(&ctx->refs); } return ret; } SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode, void __user *, arg, unsigned int, nr_args) { struct io_ring_ctx *ctx; long ret = -EBADF; struct fd f; f = fdget(fd); if (!f.file) return -EBADF; ret = -EOPNOTSUPP; if (f.file->f_op != &io_uring_fops) goto out_fput; ctx = f.file->private_data; mutex_lock(&ctx->uring_lock); ret = __io_uring_register(ctx, opcode, arg, nr_args); mutex_unlock(&ctx->uring_lock); trace_io_uring_register(ctx, opcode, ctx->nr_user_files, ctx->nr_user_bufs, ctx->cq_ev_fd != NULL, ret); out_fput: fdput(f); return ret; } static int __init io_uring_init(void) { BUILD_BUG_ON(ARRAY_SIZE(io_op_defs) != IORING_OP_LAST); req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC); return 0; }; __initcall(io_uring_init);