lazy-pages: reset poll_timeout to 0 as soon as restore is finished

It is possible that notification about restore finish arrives at the same
time with a fork event. In such case we return to epoll_run_rfds without
resetting the poll_timeout and then we'll keep polling for events
indefinitely. To avoid this, we reset the poll_timeout to 0 as soon as we
know that restore is finished.
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Andrei Vagin <avagin@virtuozzo.com>

criu/uffd.c

@@ -1231,6 +1231,8 @@ static int handle_requests(int epollfd, struct epoll_event *events, int nr_fds)
 			ret = complete_forks(epollfd, &events, &nr_fds);
 			if (ret < 0)
 				goto out;
+			if (restore_finished)
+				poll_timeout = 0;
 			if (!restore_finished || !ret)
 				continue;
 		}
@@ -1238,7 +1240,6 @@ static int handle_requests(int epollfd, struct epoll_event *events, int nr_fds)
 		/* make sure we return success if there is nothing to xfer */
 		ret = 0;
 
-		poll_timeout = 0;
 		list_for_each_entry_safe(lpi, n, &lpis, l) {
 			if (!list_empty(&lpi->iovs) && list_empty(&lpi->reqs)) {
 				ret = xfer_pages(lpi);