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 <[email protected]>
Signed-off-by: Jing Xia <[email protected]>
Signed-off-by: Xuewen Yan <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Tested-by: Brian Geffon <[email protected]>
Reviewed-by: Brian Geffon <[email protected]>
Reported-by: Benoit Lize <[email protected]>
Signed-off-by: Christian Brauner <[email protected]>

0 files changed, 0 insertions, 0 deletions