Now, the epoll only use wake_up() interface to wake up task. However, sometimes, there are epoll users which want to use the synchronous wakeup flag to hint the scheduler, such as Android binder driver. So add a wake_up_sync() define, and use the wake_up_sync() when the sync is true in ep_poll_callback(). Co-developed-by: Jing Xia <jing.xia@xxxxxxxxxx> Signed-off-by: Jing Xia <jing.xia@xxxxxxxxxx> Signed-off-by: Xuewen Yan <xuewen.yan@xxxxxxxxxx> Link: https://lore.kernel.org/r/20240426080548.8203-1-xuewen.yan@xxxxxxxxxx Tested-by: Brian Geffon <bgeffon@xxxxxxxxxx> Reviewed-by: Brian Geffon <bgeffon@xxxxxxxxxx> Reported-by: Benoit Lize <lizeb@xxxxxxxxxx> Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx> diff --git a/fs/eventpoll.c b/fs/eventpoll.c index 90fbab6b6f03..1a06e462b6ef 100644 --- a/fs/eventpoll.c +++ b/fs/eventpoll.c @@ -1373,7 +1373,10 @@ static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, v break; } } - wake_up(&ep->wq); + if (sync) + wake_up_sync(&ep->wq); + else + wake_up(&ep->wq); } if (waitqueue_active(&ep->poll_wait)) pwake++; diff --git a/include/linux/wait.h b/include/linux/wait.h index 8aa3372f21a0..2b322a9b88a2 100644 --- a/include/linux/wait.h +++ b/include/linux/wait.h @@ -221,6 +221,7 @@ void __wake_up_pollfree(struct wait_queue_head *wq_head); #define wake_up_all(x) __wake_up(x, TASK_NORMAL, 0, NULL) #define wake_up_locked(x) __wake_up_locked((x), TASK_NORMAL, 1) #define wake_up_all_locked(x) __wake_up_locked((x), TASK_NORMAL, 0) +#define wake_up_sync(x) __wake_up_sync(x, TASK_NORMAL) #define wake_up_interruptible(x) __wake_up(x, TASK_INTERRUPTIBLE, 1, NULL) #define wake_up_interruptible_nr(x, nr) __wake_up(x, TASK_INTERRUPTIBLE, nr, NULL)
