Unverified Commit ae3a4f1f authored by Jens Axboe's avatar Jens Axboe Committed by Christian Brauner
Browse files

eventpoll: add epoll_sendevents() helper 



Basic helper that copies ready events to the specified userspace
address. The event checking is quick and racy, it's up to the caller
to ensure it retries appropriately in case 0 events are copied.

Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
Link: https://lore.kernel.org/r/20250219172552.1565603-4-axboe@kernel.dk


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent 38d20356

fs/eventpoll.c

+20 −0
Original line number Diff line number Diff line
@@ -2474,6 +2474,26 @@ static int ep_check_params(struct file *file, struct epoll_event __user *evs, 
	return 0;

}



int epoll_sendevents(struct file *file, struct epoll_event __user *events,

		     int maxevents)

{

	struct eventpoll *ep;

	int ret;



	ret = ep_check_params(file, events, maxevents);

	if (unlikely(ret))

		return ret;



	ep = file->private_data;

	/*

	 * Racy call, but that's ok - it should get retried based on

	 * poll readiness anyway.

	 */

	if (ep_events_available(ep))

		return ep_try_send_events(ep, events, maxevents);

	return 0;

}



/*

 * Implement the event wait interface for the eventpoll file. It is the kernel

 * part of the user space epoll_wait(2).

include/linux/eventpoll.h

+4 −0
Original line number Diff line number Diff line
@@ -25,6 +25,10 @@ struct file *get_epoll_tfile_raw_ptr(struct file *file, int tfd, unsigned long t 
/* Used to release the epoll bits inside the "struct file" */

void eventpoll_release_file(struct file *file);



/* Copy ready events to userspace */

int epoll_sendevents(struct file *file, struct epoll_event __user *events,

		     int maxevents);



/*

 * This is called from inside fs/file_table.c:__fput() to unlink files

 * from the eventpoll interface. We need to have this facility to cleanup