bio: fix bio_kmalloc()

Impact: fix bio_kmalloc() and its destruction path

bio_kmalloc() was broken in two ways.

* bvec_alloc_bs() first allocates bvec using kmalloc() and then
  ignores it and allocates again like non-kmalloc bvecs.

* bio_kmalloc_destructor() didn't check for and free bio integrity
  data.

This patch fixes the above problems.  kmalloc patch is separated out
from bio_alloc_bioset() and allocates the requested number of bvecs as
inline bvecs.

* bio_alloc_bioset() no longer takes NULL @bs.  None other than
  bio_kmalloc() used it and outside users can't know how it was
  allocated anyway.

* Define and use BIO_POOL_NONE so that pool index check in
  bvec_free_bs() triggers if inline or kmalloc allocated bvec gets
  there.

* Relocate destructors on top of each allocation function so that how
  they're used is more clear.

Jens Axboe suggested allocating bvecs inline.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 1 insertions, 0 deletions

diff --git a/include/linux/bio.h b/include/linux/bio.h
index b89cf2d82898..7b214fd672a2 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -132,6 +132,7 @@ struct bio {
  * top 4 bits of bio flags indicate the pool this bio came from
  */
 #define BIO_POOL_BITS           (4)
+#define BIO_POOL_NONE           ((1UL << BIO_POOL_BITS) - 1)
 #define BIO_POOL_OFFSET         (BITS_PER_LONG - BIO_POOL_BITS)
 #define BIO_POOL_MASK           (1UL << BIO_POOL_OFFSET)
 #define BIO_POOL_IDX(bio)       ((bio)->bi_flags >> BIO_POOL_OFFSET)