Commit a96a9965 authored by Xuewen Yan's avatar Xuewen Yan Committed by Wen Zhiwei
Browse files

epoll: Add synchronous wakeup support for ep_poll_callback 

stable inclusion
from stable-v6.6.68
commit d9831a655e13df17009e956ad96ed87f5f23276c
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/IBMDV1

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=d9831a655e13df17009e956ad96ed87f5f23276c



--------------------------------

commit 900bbaae67e980945dec74d36f8afe0de7556d5a upstream.

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: default avatarJing Xia <jing.xia@unisoc.com>
Signed-off-by: default avatarJing Xia <jing.xia@unisoc.com>
Signed-off-by: default avatarXuewen Yan <xuewen.yan@unisoc.com>
Link: https://lore.kernel.org/r/20240426080548.8203-1-xuewen.yan@unisoc.com


Tested-by: default avatarBrian Geffon <bgeffon@google.com>
Reviewed-by: default avatarBrian Geffon <bgeffon@google.com>
Reported-by: default avatarBenoit Lize <lizeb@google.com>
Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
Cc: Brian Geffon <bgeffon@google.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarWen Zhiwei <wenzhiwei@kylinos.cn>
parent 1ace9269

fs/eventpoll.c

+4 −1
Original line number Diff line number Diff line
@@ -1268,6 +1268,9 @@ static int ep_poll_callback(wait_queue_entry_t *wait, unsigned mode, int sync, v 
				break;

			}

		}

		if (sync)

			wake_up_sync(&ep->wq);

		else

			wake_up(&ep->wq);

	}

	if (waitqueue_active(&ep->poll_wait))

include/linux/wait.h

+1 −0
Original line number Diff line number Diff line
@@ -222,6 +222,7 @@ 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)