block: don't optimize for non-cloned bio in bio_get_last_bvec()

For !BIO_CLONED bio, we can use .bi_vcnt safely, but it
doesn't mean we can just simply return .bi_io_vec[.bi_vcnt - 1]
because the start postion may have been moved in the middle of
the bvec, such as splitting in the middle of bvec.

Fixes: 7bcd79ac50d9(block: bio: introduce helpers to get the 1st and last bvec)
Cc: stable@vger.kernel.org
Reported-by: Kent Overstreet <kent.overstreet@gmail.com>
Signed-off-by: Ming Lei <ming.lei@canonical.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

1 files changed, 0 insertions, 5 deletions

diff --git a/include/linux/bio.h b/include/linux/bio.h
index cb6888824108..88bc64f00bb5 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -320,11 +320,6 @@ static inline void bio_get_last_bvec(struct bio *bio, struct bio_vec *bv)
         struct bvec_iter iter = bio->bi_iter;
         int idx;
 
-        if (!bio_flagged(bio, BIO_CLONED)) {
-                *bv = bio->bi_io_vec[bio->bi_vcnt - 1];
-                return;
-        }
-
         if (unlikely(!bio_multiple_segments(bio))) {
                 *bv = bio_iovec(bio);
                 return;