block: Require subsystems to explicitly allocate bio_set integrity mempool

MD and DM create a new bio_set for every metadevice. Each bio_set has an
integrity mempool attached regardless of whether the metadevice is
capable of passing integrity metadata. This is a waste of memory.

Instead we defer the allocation decision to MD and DM since we know at
metadevice creation time whether integrity passthrough is needed or not.

Automatic integrity mempool allocation can then be removed from
bioset_create() and we make an explicit integrity allocation for the
fs_bio_set.

Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Reported-by: Zdenek Kabelac <zkabelac@redhat.com>
Acked-by: Mike Snitzer <snizer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

2 files changed, 6 insertions, 3 deletions

diff --git a/fs/bio-integrity.c b/fs/bio-integrity.c
index e49cce234c65..9c5e6b2cd11a 100644
--- a/fs/bio-integrity.c
+++ b/fs/bio-integrity.c
@@ -761,6 +761,9 @@ int bioset_integrity_create(struct bio_set *bs, int pool_size)
 {
         unsigned int max_slab = vecs_to_idx(BIO_MAX_PAGES);
 
+        if (bs->bio_integrity_pool)
+                return 0;
+
         bs->bio_integrity_pool =
                 mempool_create_slab_pool(pool_size, bip_slab[max_slab].slab);
 
diff --git a/fs/bio.c b/fs/bio.c
index 5694b756ed01..85e2eabb1f81 100644
--- a/fs/bio.c
+++ b/fs/bio.c
@@ -1636,9 +1636,6 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
         if (!bs->bio_pool)
                 goto bad;
 
-        if (bioset_integrity_create(bs, pool_size))
-                goto bad;
-
         if (!biovec_create_pools(bs, pool_size))
                 return bs;
 
@@ -1682,6 +1679,9 @@ static int __init init_bio(void)
         if (!fs_bio_set)
                 panic("bio: can't allocate bios\n");
 
+        if (bioset_integrity_create(fs_bio_set, BIO_POOL_SIZE))
+                panic("bio: can't create integrity pool\n");
+
         bio_split_pool = mempool_create_kmalloc_pool(BIO_SPLIT_ENTRIES,
                                                      sizeof(struct bio_pair));
         if (!bio_split_pool)