io_uring: break iopolling on signal

Don't keep spinning iopoll with a signal set. It'll eventually return
back, e.g. by virtue of need_resched(), but it's not a nice user
experience.

Cc: stable@vger.kernel.org
Fixes: def596e955 ("io_uring: support for IO polling")
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/eeba551e82cad12af30c3220125eb6cb244cc94c.1691594339.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

io_uring/io_uring.c

@@ -1673,6 +1673,9 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
 			break;
 		nr_events += ret;
 		ret = 0;
+
+		if (task_sigpending(current))
+			return -EINTR;
 	} while (nr_events < min && !need_resched());
 
 	return ret;