io_uring: break iopolling on signal

[ upstream commit dc314886cb ]

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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

io_uring/io_uring.c

@@ -2668,6 +2668,11 @@ static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
 				break;
 		}
 		ret = io_do_iopoll(ctx, &nr_events, min);
+
+		if (task_sigpending(current)) {
+			ret = -EINTR;
+			goto out;
+		}
 	} while (!ret && nr_events < min && !need_resched());
 out:
 	mutex_unlock(&ctx->uring_lock);