Commit 89359897 authored by Al Viro's avatar Al Viro
Browse files

do_pollfd(): convert to CLASS(fd) 



lift setting ->revents into the caller, so that failure exits (including
the early one) would be plain returns.

We need the scope of our struct fd to end before the store to ->revents,
since that's shared with the failure exits prior to the point where we
can do fdget().

Reviewed-by: default avatarChristian Brauner <brauner@kernel.org>
Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent d000e073

fs/select.c

+11 −16
Original line number Diff line number Diff line
@@ -855,15 +855,14 @@ static inline __poll_t do_pollfd(struct pollfd *pollfd, poll_table *pwait, 
				     __poll_t busy_flag)

{

	int fd = pollfd->fd;

	__poll_t mask = 0, filter;

	struct fd f;

	__poll_t mask, filter;



	if (fd < 0)

		goto out;

	mask = EPOLLNVAL;

	f = fdget(fd);

	if (!fd_file(f))

		goto out;

		return 0;



	CLASS(fd, f)(fd);

	if (fd_empty(f))

		return EPOLLNVAL;



	/* userland u16 ->events contains POLL... bitmap */

	filter = demangle_poll(pollfd->events) | EPOLLERR | EPOLLHUP;
@@ -871,13 +870,7 @@ static inline __poll_t do_pollfd(struct pollfd *pollfd, poll_table *pwait, 
	mask = vfs_poll(fd_file(f), pwait);

	if (mask & busy_flag)

		*can_busy_poll = true;

	mask &= filter;		/* Mask out unneeded events. */

	fdput(f);



out:

	/* ... and so does ->revents */

	pollfd->revents = mangle_poll(mask);

	return mask;

	return mask & filter;		/* Mask out unneeded events. */

}



static int do_poll(struct poll_list *list, struct poll_wqueues *wait,
@@ -909,6 +902,7 @@ static int do_poll(struct poll_list *list, struct poll_wqueues *wait, 
			pfd = walk->entries;

			pfd_end = pfd + walk->len;

			for (; pfd != pfd_end; pfd++) {

				__poll_t mask;

				/*

				 * Fish for events. If we found one, record it

				 * and kill poll_table->_qproc, so we don't
@@ -916,8 +910,9 @@ static int do_poll(struct poll_list *list, struct poll_wqueues *wait, 
				 * this. They'll get immediately deregistered

				 * when we break out and return.

				 */

				if (do_pollfd(pfd, pt, &can_busy_loop,

					      busy_flag)) {

				mask = do_pollfd(pfd, pt, &can_busy_loop, busy_flag);

				pfd->revents = mangle_poll(mask);

				if (mask) {

					count++;

					pt->_qproc = NULL;

					/* found something, stop busy polling */