GuillaumeHemmen/linux
1
0
Fork 0
mirror of https://github.com/torvalds/linux.git synced 2024-11-01 13:03:25 +01:00
Code Issues Projects Releases Packages Wiki Activity

block: optimise boundary blkdev_read_iter's checks

Browse source 
Combine pos and len checks and mark unlikely. Also, don't reexpand if
it's not truncated.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/fff34e613aeaae1ad12977dc4592cb1a1f5d3190.1634755800.git.asml.silence@gmail.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Pavel Begunkov 2021-10-20 20:00:48 +01:00 committed by Jens Axboe
parent 057178cf51
commit 6450fe1f66
1 changed files with 11 additions and 8 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

19
block/fops.c
View file

@ -503,17 +503,20 @@ static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
size_t shorted = 0;
ssize_t ret;
if (pos >= size)
return 0;
size -= pos;
if (iov_iter_count(to) > size) {
shorted = iov_iter_count(to) - size;
iov_iter_truncate(to, size);
if (unlikely(pos + iov_iter_count(to) > size)) {
if (pos >= size)
return 0;
size -= pos;
if (iov_iter_count(to) > size) {
shorted = iov_iter_count(to) - size;
iov_iter_truncate(to, size);
}
}
ret = generic_file_read_iter(iocb, to);
iov_iter_reexpand(to, iov_iter_count(to) + shorted);
if (unlikely(shorted))
iov_iter_reexpand(to, iov_iter_count(to) + shorted);
return ret;
}