block: reuse BIO_INLINE_VECS for integrity bvecs

bvec_alloc always uses biovec_slabs, and thus always needs to use the
same number of inline vecs.  Share a single definition for the data
and integrity bvecs.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
diff --git a/block/blk.h b/block/blk.h
index 0198335..e022a0d 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -55,6 +55,7 @@ void blk_free_flush_queue(struct blk_flush_queue *q);
 
 void blk_freeze_queue(struct request_queue *q);
 
+#define BIO_INLINE_VECS 4
 struct bio_vec *bvec_alloc(gfp_t, int, unsigned long *, mempool_t *);
 void bvec_free(mempool_t *, struct bio_vec *, unsigned int);
 unsigned int bvec_nr_vecs(unsigned short idx);