block: don't allocate inline bvecs if this bioset needn't bvecs

The inline bvecs won't be used if user needn't bvecs by not passing
BIOSET_NEED_BVECS, so don't allocate bvecs in this situation.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Pavel Begunkov <asml.silence@gmail.com>
Tested-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2021-01-11 11:05:54 +08:00 committed by Jens Axboe
parent c495a17679
commit 9f180e315a
2 changed files with 6 additions and 2 deletions

View File

@ -89,8 +89,7 @@ fail_alloc_slab:
static inline unsigned int bs_bio_slab_size(struct bio_set *bs)
{
return bs->front_pad + sizeof(struct bio) +
BIO_INLINE_VECS * sizeof(struct bio_vec);
return bs->front_pad + sizeof(struct bio) + bs->back_pad;
}
static struct kmem_cache *bio_find_or_create_slab(struct bio_set *bs)
@ -1563,6 +1562,10 @@ int bioset_init(struct bio_set *bs,
int flags)
{
bs->front_pad = front_pad;
if (flags & BIOSET_NEED_BVECS)
bs->back_pad = BIO_INLINE_VECS * sizeof(struct bio_vec);
else
bs->back_pad = 0;
spin_lock_init(&bs->rescue_lock);
bio_list_init(&bs->rescue_list);

View File

@ -703,6 +703,7 @@ struct bio_set {
mempool_t bvec_integrity_pool;
#endif
unsigned int back_pad;
/*
* Deadlock avoidance for stacking block drivers: see comments in
* bio_alloc_bioset() for details