diff options
| -rw-r--r-- | block/blk-rq-qos.c | 4 | ||||
| -rw-r--r-- | include/linux/wait.h | 2 | ||||
| -rw-r--r-- | kernel/sched/wait.c | 9 |
3 files changed, 10 insertions, 5 deletions
diff --git a/block/blk-rq-qos.c b/block/blk-rq-qos.c index 656460636ad3..e83af7bc7591 100644 --- a/block/blk-rq-qos.c +++ b/block/blk-rq-qos.c @@ -266,8 +266,8 @@ void rq_qos_wait(struct rq_wait *rqw, void *private_data, if (!has_sleeper && acquire_inflight_cb(rqw, private_data)) return; - prepare_to_wait_exclusive(&rqw->wait, &data.wq, TASK_UNINTERRUPTIBLE); - has_sleeper = !wq_has_single_sleeper(&rqw->wait); + has_sleeper = !prepare_to_wait_exclusive(&rqw->wait, &data.wq, + TASK_UNINTERRUPTIBLE); do { /* The memory barrier in set_task_state saves us here. */ if (data.got_token) diff --git a/include/linux/wait.h b/include/linux/wait.h index fe10e8570a52..6598ae35e1b5 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -1136,7 +1136,7 @@ do { \ * Waitqueues which are removed from the waitqueue_head at wakeup time */ void prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); -void prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); +bool prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); long prepare_to_wait_event(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state); void finish_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry); long wait_woken(struct wait_queue_entry *wq_entry, unsigned mode, long timeout); diff --git a/kernel/sched/wait.c b/kernel/sched/wait.c index 183cc6ae68a6..76577d1642a5 100644 --- a/kernel/sched/wait.c +++ b/kernel/sched/wait.c @@ -264,17 +264,22 @@ prepare_to_wait(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_ent } EXPORT_SYMBOL(prepare_to_wait); -void +/* Returns true if we are the first waiter in the queue, false otherwise. */ +bool prepare_to_wait_exclusive(struct wait_queue_head *wq_head, struct wait_queue_entry *wq_entry, int state) { unsigned long flags; + bool was_empty = false; wq_entry->flags |= WQ_FLAG_EXCLUSIVE; spin_lock_irqsave(&wq_head->lock, flags); - if (list_empty(&wq_entry->entry)) + if (list_empty(&wq_entry->entry)) { + was_empty = list_empty(&wq_head->head); __add_wait_queue_entry_tail(wq_head, wq_entry); + } set_current_state(state); spin_unlock_irqrestore(&wq_head->lock, flags); + return was_empty; } EXPORT_SYMBOL(prepare_to_wait_exclusive); |