From d1376f3d89d5177dae7cae40f3f9fdf73e9bfec9 Mon Sep 17 00:00:00 2001 From: Alexander Usyskin Date: Tue, 18 Aug 2020 14:51:40 +0300 Subject: [PATCH] mei: add a spin lock to protect rd_completed queue In order to support vtags we need to access read completed queue out of driver big lock. Add a spin lock to protect rd_completed queue. Signed-off-by: Alexander Usyskin Signed-off-by: Tomas Winkler Link: https://lore.kernel.org/r/20200818115147.2567012-7-tomas.winkler@intel.com Signed-off-by: Greg Kroah-Hartman --- drivers/misc/mei/bus.c | 6 +++--- drivers/misc/mei/client.c | 47 ++++++++++++++++++++++++++++++++++++++++------ drivers/misc/mei/client.h | 7 +++++-- drivers/misc/mei/main.c | 6 +++--- drivers/misc/mei/mei_dev.h | 2 ++ 5 files changed, 54 insertions(+), 14 deletions(-) diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c index 2e7ac53..fc20a0d 100644 --- a/drivers/misc/mei/bus.c +++ b/drivers/misc/mei/bus.c @@ -152,7 +152,7 @@ ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length, if (timeout) { rets = wait_event_interruptible_timeout (cl->rx_wait, - (!list_empty(&cl->rd_completed)) || + mei_cl_read_cb(cl, NULL) || (!mei_cl_is_connected(cl)), msecs_to_jiffies(timeout)); if (rets == 0) @@ -165,7 +165,7 @@ ssize_t __mei_cl_recv(struct mei_cl *cl, u8 *buf, size_t length, } else { if (wait_event_interruptible (cl->rx_wait, - (!list_empty(&cl->rd_completed)) || + mei_cl_read_cb(cl, NULL) || (!mei_cl_is_connected(cl)))) { if (signal_pending(current)) return -EINTR; @@ -198,7 +198,7 @@ copy: rets = r_length; free: - mei_io_cb_free(cb); + mei_cl_del_rd_completed(cl, cb); out: mutex_unlock(&bus->device_lock); diff --git a/drivers/misc/mei/client.c b/drivers/misc/mei/client.c index a527995..276021f 100644 --- a/drivers/misc/mei/client.c +++ b/drivers/misc/mei/client.c @@ -507,15 +507,19 @@ struct mei_cl_cb *mei_cl_enqueue_ctrl_wr_cb(struct mei_cl *cl, size_t length, * * Return: cb on success, NULL if cb is not found */ -struct mei_cl_cb *mei_cl_read_cb(const struct mei_cl *cl, const struct file *fp) +struct mei_cl_cb *mei_cl_read_cb(struct mei_cl *cl, const struct file *fp) { struct mei_cl_cb *cb; + struct mei_cl_cb *ret_cb = NULL; + spin_lock(&cl->rd_completed_lock); list_for_each_entry(cb, &cl->rd_completed, list) - if (!fp || fp == cb->fp) - return cb; - - return NULL; + if (!fp || fp == cb->fp) { + ret_cb = cb; + break; + } + spin_unlock(&cl->rd_completed_lock); + return ret_cb; } /** @@ -541,7 +545,9 @@ int mei_cl_flush_queues(struct mei_cl *cl, const struct file *fp) mei_io_list_flush_cl(&cl->dev->ctrl_wr_list, cl); mei_io_list_flush_cl(&cl->dev->ctrl_rd_list, cl); mei_io_list_free_fp(&cl->rd_pending, fp); + spin_lock(&cl->rd_completed_lock); mei_io_list_free_fp(&cl->rd_completed, fp); + spin_unlock(&cl->rd_completed_lock); return 0; } @@ -559,6 +565,7 @@ static void mei_cl_init(struct mei_cl *cl, struct mei_device *dev) init_waitqueue_head(&cl->rx_wait); init_waitqueue_head(&cl->tx_wait); init_waitqueue_head(&cl->ev_wait); + spin_lock_init(&cl->rd_completed_lock); INIT_LIST_HEAD(&cl->rd_completed); INIT_LIST_HEAD(&cl->rd_pending); INIT_LIST_HEAD(&cl->link); @@ -1231,6 +1238,34 @@ static int mei_cl_tx_flow_ctrl_creds_reduce(struct mei_cl *cl) } /** + * mei_cl_add_rd_completed - add read completed callback to list with lock + * + * @cl: host client + * @cb: callback block + * + */ +void mei_cl_add_rd_completed(struct mei_cl *cl, struct mei_cl_cb *cb) +{ + spin_lock(&cl->rd_completed_lock); + list_add_tail(&cb->list, &cl->rd_completed); + spin_unlock(&cl->rd_completed_lock); +} + +/** + * mei_cl_del_rd_completed - free read completed callback with lock + * + * @cl: host client + * @cb: callback block + * + */ +void mei_cl_del_rd_completed(struct mei_cl *cl, struct mei_cl_cb *cb) +{ + spin_lock(&cl->rd_completed_lock); + mei_io_cb_free(cb); + spin_unlock(&cl->rd_completed_lock); +} + +/** * mei_cl_notify_fop2req - convert fop to proper request * * @fop: client notification start response command @@ -1897,7 +1932,7 @@ void mei_cl_complete(struct mei_cl *cl, struct mei_cl_cb *cb) break; case MEI_FOP_READ: - list_add_tail(&cb->list, &cl->rd_completed); + mei_cl_add_rd_completed(cl, cb); if (!mei_cl_is_fixed_address(cl) && !WARN_ON(!cl->rx_flow_ctrl_creds)) cl->rx_flow_ctrl_creds--; diff --git a/drivers/misc/mei/client.h b/drivers/misc/mei/client.h index 0d0f363..bd57c64 100644 --- a/drivers/misc/mei/client.h +++ b/drivers/misc/mei/client.h @@ -133,8 +133,11 @@ int mei_cl_unlink(struct mei_cl *cl); struct mei_cl *mei_cl_alloc_linked(struct mei_device *dev); -struct mei_cl_cb *mei_cl_read_cb(const struct mei_cl *cl, - const struct file *fp); +struct mei_cl_cb *mei_cl_read_cb(struct mei_cl *cl, const struct file *fp); + +void mei_cl_add_rd_completed(struct mei_cl *cl, struct mei_cl_cb *cb); +void mei_cl_del_rd_completed(struct mei_cl *cl, struct mei_cl_cb *cb); + struct mei_cl_cb *mei_cl_alloc_cb(struct mei_cl *cl, size_t length, enum mei_cb_file_ops type, const struct file *fp); diff --git a/drivers/misc/mei/main.c b/drivers/misc/mei/main.c index 86ef5c1..441bdea 100644 --- a/drivers/misc/mei/main.c +++ b/drivers/misc/mei/main.c @@ -178,7 +178,7 @@ static ssize_t mei_read(struct file *file, char __user *ubuf, mutex_unlock(&dev->device_lock); if (wait_event_interruptible(cl->rx_wait, - !list_empty(&cl->rd_completed) || + mei_cl_read_cb(cl, file) || !mei_cl_is_connected(cl))) { if (signal_pending(current)) return -EINTR; @@ -229,7 +229,7 @@ copy_buffer: goto out; free: - mei_io_cb_free(cb); + mei_cl_del_rd_completed(cl, cb); *offset = 0; out: @@ -572,7 +572,7 @@ static __poll_t mei_poll(struct file *file, poll_table *wait) if (req_events & (EPOLLIN | EPOLLRDNORM)) { poll_wait(file, &cl->rx_wait, wait); - if (!list_empty(&cl->rd_completed)) + if (mei_cl_read_cb(cl, file)) mask |= EPOLLIN | EPOLLRDNORM; else mei_cl_read_start(cl, mei_cl_mtu(cl), file); diff --git a/drivers/misc/mei/mei_dev.h b/drivers/misc/mei/mei_dev.h index fefa5b5..1219ede 100644 --- a/drivers/misc/mei/mei_dev.h +++ b/drivers/misc/mei/mei_dev.h @@ -217,6 +217,7 @@ struct mei_cl_cb { * @tx_cb_queued: number of tx callbacks in queue * @writing_state: state of the tx * @rd_pending: pending read credits + * @rd_completed_lock: protects rd_completed queue * @rd_completed: completed read * * @cldev: device on the mei client bus @@ -242,6 +243,7 @@ struct mei_cl { u8 tx_cb_queued; enum mei_file_transaction_states writing_state; struct list_head rd_pending; + spinlock_t rd_completed_lock; /* protects rd_completed queue */ struct list_head rd_completed; struct mei_cl_device *cldev; -- 2.7.4