The patch below does not apply to the 5.4-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
To reproduce the conflict and resubmit, you may use the following commands:
git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-5.4.y git checkout FETCH_HEAD git cherry-pick -x 900bbaae67e980945dec74d36f8afe0de7556d5a # <resolve conflicts, build, test, etc.> git commit -s git send-email --to 'stable@vger.kernel.org' --in-reply-to '2024122326-viscous-dreaded-d15d@gregkh' --subject-prefix 'PATCH 5.4.y' HEAD^..
Possible dependencies:
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 900bbaae67e980945dec74d36f8afe0de7556d5a Mon Sep 17 00:00:00 2001 From: Xuewen Yan xuewen.yan@unisoc.com Date: Fri, 26 Apr 2024 16:05:48 +0800 Subject: [PATCH] epoll: Add synchronous wakeup support for ep_poll_callback
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@unisoc.com Signed-off-by: Jing Xia jing.xia@unisoc.com Signed-off-by: Xuewen Yan xuewen.yan@unisoc.com Link: https://lore.kernel.org/r/20240426080548.8203-1-xuewen.yan@unisoc.com Tested-by: Brian Geffon bgeffon@google.com Reviewed-by: Brian Geffon bgeffon@google.com Reported-by: Benoit Lize lizeb@google.com Signed-off-by: Christian Brauner brauner@kernel.org
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)