From b7f944411b4a628443f84a542858a8c78847bb48 Mon Sep 17 00:00:00 2001 From: Ashutosh Dixit Date: Tue, 29 Sep 2015 18:10:44 -0700 Subject: misc: mic: SCIF poll SCIF poll allows both user and kernel mode clients to wait on events on a SCIF endpoint. These events include availability of space or data in the SCIF ring buffer, availability of connection requests on a listening endpoint and completion of connections when using async connects. Reviewed-by: Nikhil Rao Reviewed-by: Sudeep Dutt Signed-off-by: Ashutosh Dixit Signed-off-by: Greg Kroah-Hartman --- drivers/misc/mic/scif/scif_api.c | 158 +++++++++++++++++++++++++++++++++++++- drivers/misc/mic/scif/scif_epd.h | 22 ++++++ drivers/misc/mic/scif/scif_fd.c | 9 +++ drivers/misc/mic/scif/scif_main.h | 2 + 4 files changed, 190 insertions(+), 1 deletion(-) (limited to 'drivers/misc/mic/scif') diff --git a/drivers/misc/mic/scif/scif_api.c b/drivers/misc/mic/scif/scif_api.c index f39d3135a9ef..bf2d70fcd055 100644 --- a/drivers/misc/mic/scif/scif_api.c +++ b/drivers/misc/mic/scif/scif_api.c @@ -37,9 +37,21 @@ enum conn_async_state { ASYNC_CONN_FLUSH_WORK /* async work flush in progress */ }; +/* + * File operations for anonymous inode file associated with a SCIF endpoint, + * used in kernel mode SCIF poll. Kernel mode SCIF poll calls portions of the + * poll API in the kernel and these take in a struct file *. Since a struct + * file is not available to kernel mode SCIF, it uses an anonymous file for + * this purpose. + */ +const struct file_operations scif_anon_fops = { + .owner = THIS_MODULE, +}; + scif_epd_t scif_open(void) { struct scif_endpt *ep; + int err; might_sleep(); ep = kzalloc(sizeof(*ep), GFP_KERNEL); @@ -50,6 +62,10 @@ scif_epd_t scif_open(void) if (!ep->qp_info.qp) goto err_qp_alloc; + err = scif_anon_inode_getfile(ep); + if (err) + goto err_anon_inode; + spin_lock_init(&ep->lock); mutex_init(&ep->sendlock); mutex_init(&ep->recvlock); @@ -59,6 +75,8 @@ scif_epd_t scif_open(void) "SCIFAPI open: ep %p success\n", ep); return ep; +err_anon_inode: + kfree(ep->qp_info.qp); err_qp_alloc: kfree(ep); err_ep_alloc: @@ -279,6 +297,7 @@ int scif_close(scif_epd_t epd) } } scif_put_port(ep->port.port); + scif_anon_inode_fput(ep); scif_teardown_ep(ep); scif_add_epd_to_zombie_list(ep, !SCIF_EPLOCK_HELD); return 0; @@ -558,8 +577,10 @@ void scif_conn_handler(struct work_struct *work) list_del(&ep->conn_list); } spin_unlock(&scif_info.nb_connect_lock); - if (ep) + if (ep) { ep->conn_err = scif_conn_func(ep); + wake_up_interruptible(&ep->conn_pend_wq); + } } while (ep); } @@ -660,6 +681,7 @@ int __scif_connect(scif_epd_t epd, struct scif_port_id *dst, bool non_block) ep->remote_dev = &scif_dev[dst->node]; ep->qp_info.qp->magic = SCIFEP_MAGIC; if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) { + init_waitqueue_head(&ep->conn_pend_wq); spin_lock(&scif_info.nb_connect_lock); list_add_tail(&ep->conn_list, &scif_info.nb_connect_list); spin_unlock(&scif_info.nb_connect_lock); @@ -788,6 +810,10 @@ retry_connection: goto scif_accept_error_qpalloc; } + err = scif_anon_inode_getfile(cep); + if (err) + goto scif_accept_error_anon_inode; + cep->qp_info.qp->magic = SCIFEP_MAGIC; spdev = scif_get_peer_dev(cep->remote_dev); if (IS_ERR(spdev)) { @@ -858,6 +884,8 @@ retry: spin_unlock(&cep->lock); return 0; scif_accept_error_map: + scif_anon_inode_fput(cep); +scif_accept_error_anon_inode: scif_teardown_ep(cep); scif_accept_error_qpalloc: kfree(cep); @@ -1247,6 +1275,134 @@ int scif_recv(scif_epd_t epd, void *msg, int len, int flags) } EXPORT_SYMBOL_GPL(scif_recv); +static inline void _scif_poll_wait(struct file *f, wait_queue_head_t *wq, + poll_table *p, struct scif_endpt *ep) +{ + /* + * Because poll_wait makes a GFP_KERNEL allocation, give up the lock + * and regrab it afterwards. Because the endpoint state might have + * changed while the lock was given up, the state must be checked + * again after re-acquiring the lock. The code in __scif_pollfd(..) + * does this. + */ + spin_unlock(&ep->lock); + poll_wait(f, wq, p); + spin_lock(&ep->lock); +} + +unsigned int +__scif_pollfd(struct file *f, poll_table *wait, struct scif_endpt *ep) +{ + unsigned int mask = 0; + + dev_dbg(scif_info.mdev.this_device, + "SCIFAPI pollfd: ep %p %s\n", ep, scif_ep_states[ep->state]); + + spin_lock(&ep->lock); + + /* Endpoint is waiting for a non-blocking connect to complete */ + if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) { + _scif_poll_wait(f, &ep->conn_pend_wq, wait, ep); + if (ep->conn_async_state == ASYNC_CONN_INPROGRESS) { + if (ep->state == SCIFEP_CONNECTED || + ep->state == SCIFEP_DISCONNECTED || + ep->conn_err) + mask |= POLLOUT; + goto exit; + } + } + + /* Endpoint is listening for incoming connection requests */ + if (ep->state == SCIFEP_LISTENING) { + _scif_poll_wait(f, &ep->conwq, wait, ep); + if (ep->state == SCIFEP_LISTENING) { + if (ep->conreqcnt) + mask |= POLLIN; + goto exit; + } + } + + /* Endpoint is connected or disconnected */ + if (ep->state == SCIFEP_CONNECTED || ep->state == SCIFEP_DISCONNECTED) { + if (poll_requested_events(wait) & POLLIN) + _scif_poll_wait(f, &ep->recvwq, wait, ep); + if (poll_requested_events(wait) & POLLOUT) + _scif_poll_wait(f, &ep->sendwq, wait, ep); + if (ep->state == SCIFEP_CONNECTED || + ep->state == SCIFEP_DISCONNECTED) { + /* Data can be read without blocking */ + if (scif_rb_count(&ep->qp_info.qp->inbound_q, 1)) + mask |= POLLIN; + /* Data can be written without blocking */ + if (scif_rb_space(&ep->qp_info.qp->outbound_q)) + mask |= POLLOUT; + /* Return POLLHUP if endpoint is disconnected */ + if (ep->state == SCIFEP_DISCONNECTED) + mask |= POLLHUP; + goto exit; + } + } + + /* Return POLLERR if the endpoint is in none of the above states */ + mask |= POLLERR; +exit: + spin_unlock(&ep->lock); + return mask; +} + +/** + * scif_poll() - Kernel mode SCIF poll + * @ufds: Array of scif_pollepd structures containing the end points + * and events to poll on + * @nfds: Size of the ufds array + * @timeout_msecs: Timeout in msecs, -ve implies infinite timeout + * + * The code flow in this function is based on do_poll(..) in select.c + * + * Returns the number of endpoints which have pending events or 0 in + * the event of a timeout. If a signal is used for wake up, -EINTR is + * returned. + */ +int +scif_poll(struct scif_pollepd *ufds, unsigned int nfds, long timeout_msecs) +{ + struct poll_wqueues table; + poll_table *pt; + int i, mask, count = 0, timed_out = timeout_msecs == 0; + u64 timeout = timeout_msecs < 0 ? MAX_SCHEDULE_TIMEOUT + : msecs_to_jiffies(timeout_msecs); + + poll_initwait(&table); + pt = &table.pt; + while (1) { + for (i = 0; i < nfds; i++) { + pt->_key = ufds[i].events | POLLERR | POLLHUP; + mask = __scif_pollfd(ufds[i].epd->anon, + pt, ufds[i].epd); + mask &= ufds[i].events | POLLERR | POLLHUP; + if (mask) { + count++; + pt->_qproc = NULL; + } + ufds[i].revents = mask; + } + pt->_qproc = NULL; + if (!count) { + count = table.error; + if (signal_pending(current)) + count = -EINTR; + } + if (count || timed_out) + break; + + if (!schedule_timeout_interruptible(timeout)) + timed_out = 1; + } + poll_freewait(&table); + return count; +} +EXPORT_SYMBOL_GPL(scif_poll); + int scif_get_node_ids(u16 *nodes, int len, u16 *self) { int online = 0; diff --git a/drivers/misc/mic/scif/scif_epd.h b/drivers/misc/mic/scif/scif_epd.h index 331322a25213..4dc4ccdbc236 100644 --- a/drivers/misc/mic/scif/scif_epd.h +++ b/drivers/misc/mic/scif/scif_epd.h @@ -96,7 +96,9 @@ struct scif_endpt_qp_info { * @conn_port: Connection port * @conn_err: Errors during connection * @conn_async_state: Async connection + * @conn_pend_wq: Used by poll while waiting for incoming connections * @conn_list: List of async connection requests + * @anon: anonymous file for use in kernel mode scif poll */ struct scif_endpt { enum scif_epd_state state; @@ -125,7 +127,9 @@ struct scif_endpt { struct scif_port_id conn_port; int conn_err; int conn_async_state; + wait_queue_head_t conn_pend_wq; struct list_head conn_list; + struct file *anon; }; static inline int scifdev_alive(struct scif_endpt *ep) @@ -133,6 +137,22 @@ static inline int scifdev_alive(struct scif_endpt *ep) return _scifdev_alive(ep->remote_dev); } +static inline int scif_anon_inode_getfile(scif_epd_t epd) +{ + epd->anon = anon_inode_getfile("scif", &scif_anon_fops, NULL, 0); + if (IS_ERR(epd->anon)) + return PTR_ERR(epd->anon); + return 0; +} + +static inline void scif_anon_inode_fput(scif_epd_t epd) +{ + if (epd->anon) { + fput(epd->anon); + epd->anon = NULL; + } +} + void scif_cleanup_zombie_epd(void); void scif_teardown_ep(void *endpt); void scif_cleanup_ep_qp(struct scif_endpt *ep); @@ -157,4 +177,6 @@ void scif_clientsend(struct scif_dev *scifdev, struct scifmsg *msg); void scif_clientrcvd(struct scif_dev *scifdev, struct scifmsg *msg); int __scif_connect(scif_epd_t epd, struct scif_port_id *dst, bool non_block); int __scif_flush(scif_epd_t epd); +unsigned int __scif_pollfd(struct file *f, poll_table *wait, + struct scif_endpt *ep); #endif /* SCIF_EPD_H */ diff --git a/drivers/misc/mic/scif/scif_fd.c b/drivers/misc/mic/scif/scif_fd.c index eccf7e7135f9..24e47f73e45a 100644 --- a/drivers/misc/mic/scif/scif_fd.c +++ b/drivers/misc/mic/scif/scif_fd.c @@ -34,6 +34,13 @@ static int scif_fdclose(struct inode *inode, struct file *f) return scif_close(priv); } +static unsigned int scif_fdpoll(struct file *f, poll_table *wait) +{ + struct scif_endpt *priv = f->private_data; + + return __scif_pollfd(f, wait, priv); +} + static int scif_fdflush(struct file *f, fl_owner_t id) { struct scif_endpt *ep = f->private_data; @@ -193,6 +200,7 @@ static long scif_fdioctl(struct file *f, unsigned int cmd, unsigned long arg) spin_unlock(&scif_info.eplock); /* Free the resources automatically created from the open. */ + scif_anon_inode_fput(priv); scif_teardown_ep(priv); scif_add_epd_to_zombie_list(priv, !SCIF_EPLOCK_HELD); f->private_data = newep; @@ -298,6 +306,7 @@ const struct file_operations scif_fops = { .open = scif_fdopen, .release = scif_fdclose, .unlocked_ioctl = scif_fdioctl, + .poll = scif_fdpoll, .flush = scif_fdflush, .owner = THIS_MODULE, }; diff --git a/drivers/misc/mic/scif/scif_main.h b/drivers/misc/mic/scif/scif_main.h index 580bc63e1b23..87c13279a8f0 100644 --- a/drivers/misc/mic/scif/scif_main.h +++ b/drivers/misc/mic/scif/scif_main.h @@ -22,6 +22,7 @@ #include #include #include +#include #include #include @@ -184,6 +185,7 @@ extern struct scif_info scif_info; extern struct idr scif_ports; extern struct scif_dev *scif_dev; extern const struct file_operations scif_fops; +extern const struct file_operations scif_anon_fops; /* Size of the RB for the Node QP */ #define SCIF_NODE_QP_SIZE 0x10000 -- cgit v1.2.3