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>

1 files changed, 5 insertions, 2 deletions

diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c
index f50a7b952257..416d4e258df6 100644
--- a/drivers/md/dm-table.c
+++ b/drivers/md/dm-table.c
@@ -55,6 +55,7 @@ struct dm_table {
         struct dm_target *targets;
 
         unsigned discards_supported:1;
+        unsigned integrity_supported:1;
 
         /*
          * Indicates the rw permissions for the new logical
@@ -859,7 +860,7 @@ int dm_table_alloc_md_mempools(struct dm_table *t)
                 return -EINVAL;
         }
 
-        t->mempools = dm_alloc_md_mempools(type);
+        t->mempools = dm_alloc_md_mempools(type, t->integrity_supported);
         if (!t->mempools)
                 return -ENOMEM;
 
@@ -935,8 +936,10 @@ static int dm_table_prealloc_integrity(struct dm_table *t, struct mapped_device
         struct dm_dev_internal *dd;
 
         list_for_each_entry(dd, devices, list)
-                if (bdev_get_integrity(dd->dm_dev.bdev))
+                if (bdev_get_integrity(dd->dm_dev.bdev)) {
+                        t->integrity_supported = 1;
                         return blk_integrity_register(dm_disk(md), NULL);
+                }
 
         return 0;
 }