/* * Copyright (C) 2016 Red Hat, Inc. All rights reserved. * * This file is released under the GPL. */ #include "dm-core.h" #include "dm-rq.h" #include <linux/elevator.h> /* for rq_end_sector() */ #include <linux/blk-mq.h> #define DM_MSG_PREFIX "core-rq" /* * One of these is allocated per request. */ struct dm_rq_target_io { struct mapped_device *md; struct dm_target *ti; struct request *orig, *clone; struct kthread_work work; blk_status_t error; union map_info info; struct dm_stats_aux stats_aux; unsigned long duration_jiffies; unsigned n_sectors; unsigned completed; }; #define DM_MQ_NR_HW_QUEUES 1 #define DM_MQ_QUEUE_DEPTH 2048 static unsigned dm_mq_nr_hw_queues = DM_MQ_NR_HW_QUEUES; static unsigned dm_mq_queue_depth = DM_MQ_QUEUE_DEPTH; /* * Request-based DM's mempools' reserved IOs set by the user. */ #define RESERVED_REQUEST_BASED_IOS 256 static unsigned reserved_rq_based_ios = RESERVED_REQUEST_BASED_IOS; unsigned dm_get_reserved_rq_based_ios(void) { return __dm_get_module_param(&reserved_rq_based_ios, RESERVED_REQUEST_BASED_IOS, DM_RESERVED_MAX_IOS); } EXPORT_SYMBOL_GPL(dm_get_reserved_rq_based_ios); static unsigned dm_get_blk_mq_nr_hw_queues(void) { return __dm_get_module_param(&dm_mq_nr_hw_queues, 1, 32); } static unsigned dm_get_blk_mq_queue_depth(void) { return __dm_get_module_param(&dm_mq_queue_depth, DM_MQ_QUEUE_DEPTH, BLK_MQ_MAX_DEPTH); } int dm_request_based(struct mapped_device *md) { return queue_is_mq(md->queue); } void dm_start_queue(struct request_queue *q) { blk_mq_unquiesce_queue(q); blk_mq_kick_requeue_list(q); } void dm_stop_queue(struct request_queue *q) { if (blk_mq_queue_stopped(q)) return; blk_mq_quiesce_queue(q); } /* * Partial completion handling for request-based dm */ static void end_clone_bio(struct bio *clone) { struct dm_rq_clone_bio_info *info = container_of(clone, struct dm_rq_clone_bio_info, clone); struct dm_rq_target_io *tio = info->tio; unsigned int nr_bytes = info->orig->bi_iter.bi_size; blk_status_t error = clone->bi_status; bool is_last = !clone->bi_next; bio_put(clone); if (tio->error) /* * An error has already been detected on the request. * Once error occurred, just let clone->end_io() handle * the remainder. */ return; else if (error) { /* * Don't notice the error to the upper layer yet. * The error handling decision is made by the target driver, * when the request is completed. */ tio->error = error; goto exit; } /* * I/O for the bio successfully completed. * Notice the data completion to the upper layer. */ tio->completed += nr_bytes; /* * Update the original request. * Do not use blk_mq_end_request() here, because it may complete * the original request before the clone, and break the ordering. */ if (is_last) exit: blk_update_request(tio->orig, BLK_STS_OK, tio->completed); } static struct dm_rq_target_io *tio_from_request(struct request *rq) { return blk_mq_rq_to_pdu(rq); } static void rq_end_stats(struct mapped_device *md, struct request *orig) { if (unlikely(dm_stats_used(&md->stats))) { struct dm_rq_target_io *tio = tio_from_request(orig); tio->duration_jiffies = jiffies - tio->duration_jiffies; dm_stats_account_io(&md->stats, rq_data_dir(orig), blk_rq_pos(orig), tio->n_sectors, true, tio->duration_jiffies, &tio->stats_aux); } } /* * Don't touch any member of the md after calling this function because * the md may be freed in dm_put() at the end of this function. * Or do dm_get() before calling this function and dm_put() later. */ static void rq_completed(struct mapped_device *md) { /* nudge anyone waiting on suspend queue */ if (unlikely(wq_has_sleeper(&md->wait))) wake_up(&md->wait); /* * dm_put() must be at the end of this function. See the comment above */ dm_put(md); } /* * Complete the clone and the original request. * Must be called without clone's queue lock held, * see end_clone_request() for more details. */ static void dm_end_request(struct request *clone, blk_status_t error) { struct dm_rq_target_io *tio = clone->end_io_data; struct mapped_device *md = tio->md; struct request *rq = tio->orig; blk_rq_unprep_clone(clone); tio->ti->type->release_clone_rq(clone, NULL); rq_end_stats(md, rq); blk_mq_end_request(rq, error); rq_completed(md); } static void __dm_mq_kick_requeue_list(struct request_queue *q, unsigned long msecs) { blk_mq_delay_kick_requeue_list(q, msecs); } void dm_mq_kick_requeue_list(struct mapped_device *md) { __dm_mq_kick_requeue_list(dm_get_md_queue(md), 0); } EXPORT_SYMBOL(dm_mq_kick_requeue_list); static void dm_mq_delay_requeue_request(struct request *rq, unsigned long msecs) { blk_mq_requeue_request(rq, false); __dm_mq_kick_requeue_list(rq->q, msecs); } static void dm_requeue_original_request(struct dm_rq_target_io *tio, bool delay_requeue) { struct mapped_device *md = tio->md; struct request *rq = tio->orig; unsigned long delay_ms = delay_requeue ? 100 : 0; rq_end_stats(md, rq); if (tio->clone) { blk_rq_unprep_clone(tio->clone); tio->ti->type->release_clone_rq(tio->clone, NULL); } dm_mq_delay_requeue_request(rq, delay_ms); rq_completed(md); } static void dm_done(struct request *clone, blk_status_t error, bool mapped) { int r = DM_ENDIO_DONE; struct dm_rq_target_io *tio = clone->end_io_data; dm_request_endio_fn rq_end_io = NULL; if (tio->ti) { rq_end_io = tio->ti->type->rq_end_io; if (mapped && rq_end_io) r = rq_end_io(tio->ti, clone, error, &tio->info); } if (unlikely(error == BLK_STS_TARGET)) { if (req_op(clone) == REQ_OP_DISCARD && !clone->q->limits.max_discard_sectors) disable_discard(tio->md); else if (req_op(clone) == REQ_OP_WRITE_SAME && !clone->q->limits.max_write_same_sectors) disable_write_same(tio->md); else if (req_op(clone) == REQ_OP_WRITE_ZEROES && !clone->q->limits.max_write_zeroes_sectors) disable_write_zeroes(tio->md); } switch (r) { case DM_ENDIO_DONE: /* The target wants to complete the I/O */ dm_end_request(clone, error); break; case DM_ENDIO_INCOMPLETE: /* The target will handle the I/O */ return; case DM_ENDIO_REQUEUE: /* The target wants to requeue the I/O */ dm_requeue_original_request(tio, false); break; case DM_ENDIO_DELAY_REQUEUE: /* The target wants to requeue the I/O after a delay */ dm_requeue_original_request(tio, true); break; default: DMWARN("unimplemented target endio return value: %d", r); BUG(); } } /* * Request completion handler for request-based dm */ static void dm_softirq_done(struct request *rq) { bool mapped = true; struct dm_rq_target_io *tio = tio_from_request(rq); struct request *clone = tio->clone; if (!clone) { struct mapped_device *md = tio->md; rq_end_stats(md, rq); blk_mq_end_request(rq, tio->error); rq_completed(md); return; } if (rq->rq_flags & RQF_FAILED) mapped = false; dm_done(clone, tio->error, mapped); } /* * Complete the clone and the original request with the error status * through softirq context. */ static void dm_complete_request(struct request *rq, blk_status_t error) { struct dm_rq_target_io *tio = tio_from_request(rq); tio->error = error; blk_mq_complete_request(rq); } /* * Complete the not-mapped clone and the original request with the error status * through softirq context. * Target's rq_end_io() function isn't called. * This may be used when the target's clone_and_map_rq() function fails. */ static void dm_kill_unmapped_request(struct request *rq, blk_status_t error) { rq->rq_flags |= RQF_FAILED; dm_complete_request(rq, error); } static void end_clone_request(struct request *clone, blk_status_t error) { struct dm_rq_target_io *tio = clone->end_io_data; dm_complete_request(tio->orig, error); } static blk_status_t dm_dispatch_clone_request(struct request *clone, struct request *rq) { blk_status_t r; if (blk_queue_io_stat(clone->q)) clone->rq_flags |= RQF_IO_STAT; clone->start_time_ns = ktime_get_ns(); r = blk_insert_cloned_request(clone->q, clone); if (r != BLK_STS_OK && r != BLK_STS_RESOURCE && r != BLK_STS_DEV_RESOURCE) /* must complete clone in terms of original request */ dm_complete_request(rq, r); return r; } static int dm_rq_bio_constructor(struct bio *bio, struct bio *bio_orig, void *data) { struct dm_rq_target_io *tio = data; struct dm_rq_clone_bio_info *info = container_of(bio, struct dm_rq_clone_bio_info, clone); info->orig = bio_orig; info->tio = tio; bio->bi_end_io = end_clone_bio; return 0; } static int setup_clone(struct request *clone, struct request *rq, struct dm_rq_target_io *tio, gfp_t gfp_mask) { int r; r = blk_rq_prep_clone(clone, rq, &tio->md->bs, gfp_mask, dm_rq_bio_constructor, tio); if (r) return r; clone->end_io = end_clone_request; clone->end_io_data = tio; tio->clone = clone; return 0; } static void init_tio(struct dm_rq_target_io *tio, struct request *rq, struct mapped_device *md) { tio->md = md; tio->ti = NULL; tio->clone = NULL; tio->orig = rq; tio->error = 0; tio->completed = 0; /* * Avoid initializing info for blk-mq; it passes * target-specific data through info.ptr * (see: dm_mq_init_request) */ if (!md->init_tio_pdu) memset(&tio->info, 0, sizeof(tio->info)); } /* * Returns: * DM_MAPIO_* : the request has been processed as indicated * DM_MAPIO_REQUEUE : the original request needs to be immediately requeued * < 0 : the request was completed due to failure */ static int map_request(struct dm_rq_target_io *tio) { int r; struct dm_target *ti = tio->ti; struct mapped_device *md = tio->md; struct request *rq = tio->orig; struct request *clone = NULL; blk_status_t ret; r = ti->type->clone_and_map_rq(ti, rq, &tio->info, &clone); switch (r) { case DM_MAPIO_SUBMITTED: /* The target has taken the I/O to submit by itself later */ break; case DM_MAPIO_REMAPPED: if (setup_clone(clone, rq, tio, GFP_ATOMIC)) { /* -ENOMEM */ ti->type->release_clone_rq(clone, &tio->info); return DM_MAPIO_REQUEUE; } /* The target has remapped the I/O so dispatch it */ trace_block_rq_remap(clone->q, clone, disk_devt(dm_disk(md)), blk_rq_pos(rq)); ret = dm_dispatch_clone_request(clone, rq); if (ret == BLK_STS_RESOURCE || ret == BLK_STS_DEV_RESOURCE) { blk_rq_unprep_clone(clone); tio->ti->type->release_clone_rq(clone, &tio->info); tio->clone = NULL; return DM_MAPIO_REQUEUE; } break; case DM_MAPIO_REQUEUE: /* The target wants to requeue the I/O */ break; case DM_MAPIO_DELAY_REQUEUE: /* The target wants to requeue the I/O after a delay */ dm_requeue_original_request(tio, true); break; case DM_MAPIO_KILL: /* The target wants to complete the I/O */ dm_kill_unmapped_request(rq, BLK_STS_IOERR); break; default: DMWARN("unimplemented target map return value: %d", r); BUG(); } return r; } /* DEPRECATED: previously used for request-based merge heuristic in dm_request_fn() */ ssize_t dm_attr_rq_based_seq_io_merge_deadline_show(struct mapped_device *md, char *buf) { return sprintf(buf, "%u\n", 0); } ssize_t dm_attr_rq_based_seq_io_merge_deadline_store(struct mapped_device *md, const char *buf, size_t count) { return count; } static void dm_start_request(struct mapped_device *md, struct request *orig) { blk_mq_start_request(orig); if (unlikely(dm_stats_used(&md->stats))) { struct dm_rq_target_io *tio = tio_from_request(orig); tio->duration_jiffies = jiffies; tio->n_sectors = blk_rq_sectors(orig); dm_stats_account_io(&md->stats, rq_data_dir(orig), blk_rq_pos(orig), tio->n_sectors, false, 0, &tio->stats_aux); } /* * Hold the md reference here for the in-flight I/O. * We can't rely on the reference count by device opener, * because the device may be closed during the request completion * when all bios are completed. * See the comment in rq_completed() too. */ dm_get(md); } static int dm_mq_init_request(struct blk_mq_tag_set *set, struct request *rq, unsigned int hctx_idx, unsigned int numa_node) { struct mapped_device *md = set->driver_data; struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq); /* * Must initialize md member of tio, otherwise it won't * be available in dm_mq_queue_rq. */ tio->md = md; if (md->init_tio_pdu) { /* target-specific per-io data is immediately after the tio */ tio->info.ptr = tio + 1; } return 0; } static blk_status_t dm_mq_queue_rq(struct blk_mq_hw_ctx *hctx, const struct blk_mq_queue_data *bd) { struct request *rq = bd->rq; struct dm_rq_target_io *tio = blk_mq_rq_to_pdu(rq); struct mapped_device *md = tio->md; struct dm_target *ti = md->immutable_target; if (unlikely(!ti)) { int srcu_idx; struct dm_table *map = dm_get_live_table(md, &srcu_idx); ti = dm_table_find_target(map, 0); dm_put_live_table(md, srcu_idx); } if (ti->type->busy && ti->type->busy(ti)) return BLK_STS_RESOURCE; dm_start_request(md, rq); /* Init tio using md established in .init_request */ init_tio(tio, rq, md); /* * Establish tio->ti before calling map_request(). */ tio->ti = ti; /* Direct call is fine since .queue_rq allows allocations */ if (map_request(tio) == DM_MAPIO_REQUEUE) { /* Undo dm_start_request() before requeuing */ rq_end_stats(md, rq); rq_completed(md); return BLK_STS_RESOURCE; } return BLK_STS_OK; } static const struct blk_mq_ops dm_mq_ops = { .queue_rq = dm_mq_queue_rq, .complete = dm_softirq_done, .init_request = dm_mq_init_request, }; int dm_mq_init_request_queue(struct mapped_device *md, struct dm_table *t) { struct request_queue *q; struct dm_target *immutable_tgt; int err; md->tag_set = kzalloc_node(sizeof(struct blk_mq_tag_set), GFP_KERNEL, md->numa_node_id); if (!md->tag_set) return -ENOMEM; md->tag_set->ops = &dm_mq_ops; md->tag_set->queue_depth = dm_get_blk_mq_queue_depth(); md->tag_set->numa_node = md->numa_node_id; md->tag_set->flags = BLK_MQ_F_SHOULD_MERGE; md->tag_set->nr_hw_queues = dm_get_blk_mq_nr_hw_queues(); md->tag_set->driver_data = md; md->tag_set->cmd_size = sizeof(struct dm_rq_target_io); immutable_tgt = dm_table_get_immutable_target(t); if (immutable_tgt && immutable_tgt->per_io_data_size) { /* any target-specific per-io data is immediately after the tio */ md->tag_set->cmd_size += immutable_tgt->per_io_data_size; md->init_tio_pdu = true; } err = blk_mq_alloc_tag_set(md->tag_set); if (err) goto out_kfree_tag_set; q = blk_mq_init_allocated_queue(md->tag_set, md->queue); if (IS_ERR(q)) { err = PTR_ERR(q); goto out_tag_set; } return 0; out_tag_set: blk_mq_free_tag_set(md->tag_set); out_kfree_tag_set: kfree(md->tag_set); return err; } void dm_mq_cleanup_mapped_device(struct mapped_device *md) { if (md->tag_set) { blk_mq_free_tag_set(md->tag_set); kfree(md->tag_set); } } module_param(reserved_rq_based_ios, uint, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(reserved_rq_based_ios, "Reserved IOs in request-based mempools"); /* Unused, but preserved for userspace compatibility */ static bool use_blk_mq = true; module_param(use_blk_mq, bool, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(use_blk_mq, "Use block multiqueue for request-based DM devices"); module_param(dm_mq_nr_hw_queues, uint, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(dm_mq_nr_hw_queues, "Number of hardware queues for request-based dm-mq devices"); module_param(dm_mq_queue_depth, uint, S_IRUGO | S_IWUSR); MODULE_PARM_DESC(dm_mq_queue_depth, "Queue depth for request-based dm-mq devices");