]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
io_uring: fix manual setup of iov_iter for fixed buffers
authorAleix Roca Nonell <aleix.rocanonell@bsc.es>
Thu, 15 Aug 2019 12:03:22 +0000 (14:03 +0200)
committerJens Axboe <axboe@kernel.dk>
Thu, 15 Aug 2019 17:03:38 +0000 (11:03 -0600)
commit99c79f6692ccdc42e04deea8a36e22bb48168a62
treed665a31392cb938848e7a17e21d7fe2b034ed862
parentae78ca3cf3d9e9f914bfcd0bc5c389ff18b9c2e0
io_uring: fix manual setup of iov_iter for fixed buffers

Commit bd11b3a391e3 ("io_uring: don't use iov_iter_advance() for fixed
buffers") introduced an optimization to avoid using the slow
iov_iter_advance by manually populating the iov_iter iterator in some
cases.

However, the computation of the iterator count field was erroneous: The
first bvec was always accounted for an extent of page size even if the
bvec length was smaller.

In consequence, some I/O operations on fixed buffers were unable to
operate on the full extent of the buffer, consistently skipping some
bytes at the end of it.

Fixes: bd11b3a391e3 ("io_uring: don't use iov_iter_advance() for fixed buffers")
Cc: stable@vger.kernel.org
Signed-off-by: Aleix Roca Nonell <aleix.rocanonell@bsc.es>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
fs/io_uring.c