[PATCH 2/2] bio: Free own bvec before assigning the source bio's bvec

[Minfei Huang <mnfhuang@gmail.com>]

This is a memory leaking during splitting the bio by the caller
bio_clone_fast.

Clone bio may allocate its own bvec, if demanding bvec is more than
inline bvec in function bio_alloc_bioset.

bi_io_vec is assigned to the source bio's bvec directly without freeing
it firstly in function __bio_clone_fast.

To fix it, freeing the own bvec firstly before assigning the source
bio's bvec.

Signed-off-by: Minfei Huang <mnfhuang@gmail.com>
---
 block/bio.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/block/bio.c b/block/bio.c
index 70d9814..b24fd6e 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -581,6 +581,10 @@ void __bio_clone_fast(struct bio *bio, struct bio *bio_src)
 	bio_set_flag(bio, BIO_CLONED);
 	bio->bi_rw = bio_src->bi_rw;
 	bio->bi_iter = bio_src->bi_iter;
+
+	if (bio_flagged(bio, BIO_OWNS_VEC))
+		bvec_free(bio->bi_pool->bvec_pool,
+				bio->bi_io_vec, BIO_POOL_IDX(bio));
 	bio->bi_io_vec = bio_src->bi_io_vec;
 }
 EXPORT_SYMBOL(__bio_clone_fast);
-- 
2.6.3