block: Fix for_each_bvec()

Commit 4550dd6c6b introduced for_each_bvec() which iterates over each
bvec attached to a bio or bip. However, the macro fails to check bi_size
before dereferencing which can lead to crashes while counting/mapping
integrity scatterlist segments.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Cc: Kent Overstreet <kmo@daterainc.com>
Cc: Nicholas Bellinger <nab@linux-iscsi.org>
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Martin K. Petersen 2014-04-08 22:43:43 -04:00 committed by Jens Axboe
parent 44bd70c347
commit b7aa84d9cb

View File

@ -216,9 +216,9 @@ static inline void bvec_iter_advance(struct bio_vec *bv, struct bvec_iter *iter,
}
#define for_each_bvec(bvl, bio_vec, iter, start) \
for ((iter) = start; \
(bvl) = bvec_iter_bvec((bio_vec), (iter)), \
(iter).bi_size; \
for (iter = (start); \
(iter).bi_size && \
((bvl = bvec_iter_bvec((bio_vec), (iter))), 1); \
bvec_iter_advance((bio_vec), &(iter), (bvl).bv_len))