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

commit 16c8d2df7ec0eed31b7d3b61cb13206a7fb930cc upstream.

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: 4017eb91a9e7 ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/fs/io_uring.c b/fs/io_uring.c
index d0089039fee7986d0f4aa7ecf9cde606ad9690a1..a8d07273ddc05049c4b45991b86d1e6f6b7ac014 100644 (file)
--- a/fs/io_uring.c
+++ b/fs/io_uring.c
@@ -3206,12 +3206,15 @@ static ssize_t loop_rw_iter(int rw, struct io_kiocb *req, struct iov_iter *iter)
                                ret = nr;
                        break;
                }
+               if (!iov_iter_is_bvec(iter)) {
+                       iov_iter_advance(iter, nr);
+               } else {
+                       req->rw.len -= nr;
+                       req->rw.addr += nr;
+               }
                ret += nr;
                if (nr != iovec.iov_len)
                        break;
-               req->rw.len -= nr;
-               req->rw.addr += nr;
-               iov_iter_advance(iter, nr);
        }
 
        return ret;