Unverified Commit 0511f4e6 authored by Christian Brauner's avatar Christian Brauner
Browse files

Merge patch series "epoll changes for io_uring wait support" 

Bring in the preparatory epoll changes for io_uring epoll support.

* patches from https://lore.kernel.org/r/20250219172552.1565603-1-axboe@kernel.dk:
  eventpoll: add epoll_sendevents() helper
  eventpoll: abstract out ep_try_send_events() helper
  eventpoll: abstract out parameter sanity checking

Link: https://lore.kernel.org/r/20250219172552.1565603-1-axboe@kernel.dk


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parents 2014c95a ae3a4f1f

fs/eventpoll.c

+63 −24
Original line number Diff line number Diff line
@@ -1980,6 +1980,22 @@ static int ep_autoremove_wake_function(struct wait_queue_entry *wq_entry, 
	return ret;

}



static int ep_try_send_events(struct eventpoll *ep,

			      struct epoll_event __user *events, int maxevents)

{

	int res;



	/*

	 * Try to transfer events to user space. In case we get 0 events and

	 * there's still timeout left over, we go trying again in search of

	 * more luck.

	 */

	res = ep_send_events(ep, events, maxevents);

	if (res > 0)

		ep_suspend_napi_irqs(ep);

	return res;

}



/**

 * ep_poll - Retrieves ready events, and delivers them to the caller-supplied

 *           event buffer.
@@ -2031,18 +2047,10 @@ static int ep_poll(struct eventpoll *ep, struct epoll_event __user *events, 


	while (1) {

		if (eavail) {

			/*

			 * Try to transfer events to user space. In case we get

			 * 0 events and there's still timeout left over, we go

			 * trying again in search of more luck.

			 */

			res = ep_send_events(ep, events, maxevents);

			if (res) {

				if (res > 0)

					ep_suspend_napi_irqs(ep);

			res = ep_try_send_events(ep, events, maxevents);

			if (res)

				return res;

		}

		}



		if (timed_out)

			return 0;
@@ -2445,6 +2453,47 @@ SYSCALL_DEFINE4(epoll_ctl, int, epfd, int, op, int, fd, 
	return do_epoll_ctl(epfd, op, fd, &epds, false);

}



static int ep_check_params(struct file *file, struct epoll_event __user *evs,

			   int maxevents)

{

	/* The maximum number of event must be greater than zero */

	if (maxevents <= 0 || maxevents > EP_MAX_EVENTS)

		return -EINVAL;



	/* Verify that the area passed by the user is writeable */

	if (!access_ok(evs, maxevents * sizeof(struct epoll_event)))

		return -EFAULT;



	/*

	 * We have to check that the file structure underneath the fd

	 * the user passed to us _is_ an eventpoll file.

	 */

	if (!is_file_epoll(file))

		return -EINVAL;



	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).
@@ -2453,26 +2502,16 @@ static int do_epoll_wait(int epfd, struct epoll_event __user *events, 
			 int maxevents, struct timespec64 *to)

{

	struct eventpoll *ep;



	/* The maximum number of event must be greater than zero */

	if (maxevents <= 0 || maxevents > EP_MAX_EVENTS)

		return -EINVAL;



	/* Verify that the area passed by the user is writeable */

	if (!access_ok(events, maxevents * sizeof(struct epoll_event)))

		return -EFAULT;

	int ret;



	/* Get the "struct file *" for the eventpoll file */

	CLASS(fd, f)(epfd);

	if (fd_empty(f))

		return -EBADF;



	/*

	 * We have to check that the file structure underneath the fd

	 * the user passed to us _is_ an eventpoll file.

	 */

	if (!is_file_epoll(fd_file(f)))

		return -EINVAL;

	ret = ep_check_params(fd_file(f), events, maxevents);

	if (unlikely(ret))

		return ret;



	/*

	 * At this point it is safe to assume that the "private_data" contains

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