Commit 16c8d2df authored Sep 12, 2021 by Jens Axboe

io_uring: ensure symmetry in handling iter types in loop_rw_iter()



When setting up the next segment, we check what type the iter is and
handle it accordingly. However, when incrementing and processed amount
we do not, and both iter advance and addr/len are adjusted, regardless
of type. Split the increment side just like we do on the setup side.

Fixes: 4017eb91 ("io_uring: make loop_rw_iter() use original user supplied pointers")
Cc: stable@vger.kernel.org
Reported-by: Valentina Palmiotti <vpalmiotti@gmail.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent 6880fa6c

fs/io_uring.c

+6 −3

Original line number	Original line	Diff line number	Diff line
	@@ -3263,12 +3263,15 @@ static ssize_t loop_rw_iter(int rw, struct io_kiocb req, struct iov_iter iter)
	ret = nr;		ret = nr;
	break;		break;
	}		}
			if (!iov_iter_is_bvec(iter)) {
			iov_iter_advance(iter, nr);
			} else {
			req->rw.len -= nr;
			req->rw.addr += nr;
			}
	ret += nr;		ret += nr;
	if (nr != iovec.iov_len)		if (nr != iovec.iov_len)
	break;		break;
	req->rw.len -= nr;
	req->rw.addr += nr;
	iov_iter_advance(iter, nr);
	}		}

	return ret;		return ret;