Combine pos and len checks and mark unlikely. Also, don't reexpand if it's not truncated. Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx> --- block/fops.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/block/fops.c b/block/fops.c index 21d25ee0e4bf..8f733c919ed1 100644 --- a/block/fops.c +++ b/block/fops.c @@ -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; } -- 2.33.1