io_uring: convert accept4() -ERESTARTSYS into -EINTR

commit 8e3cca12706231daf8daf90dbde59f1665135e48 upstream.

If we cancel a pending accept operating with a signal, we get
-ERESTARTSYS returned. Turn that into -EINTR for userspace, we should
not be return -ERESTARTSYS.

Fixes: 17f2fe35d080 ("io_uring: add support for IORING_OP_ACCEPT")
Reported-by: NHrvoje Zeba <zeba.hrvoje@gmail.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NJoseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: NXiaoguang Wang <xiaoguang.wang@linux.alibaba.com>

fs/io_uring.c

@@ -1887,6 +1887,8 @@ static int io_accept(struct io_kiocb *req, const struct io_uring_sqe *sqe,
 		req->work.flags |= IO_WQ_WORK_NEEDS_FILES;
 		return -EAGAIN;
 	}
+	if (ret == -ERESTARTSYS)
+		ret = -EINTR;
 	if (ret < 0 && (req->flags & REQ_F_LINK))
 		req->flags |= REQ_F_FAIL_LINK;
 	io_cqring_add_event(req, ret);