dm persistent data: create new dm_block_manager struct

This patch introduces a separate struct for the block_manager.
It also uses IS_ERR to check the return value of dm_bufio_client_create
instead of testing incorrectly for NULL.

Prior to this patch a struct dm_block_manager was really an alias for
a struct dm_bufio_client.  We want to add some functionality to the
block manager that will require extra fields, so this one to one
mapping is no longer valid.

Signed-off-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/drivers/md/dm-thin-metadata.c b/drivers/md/dm-thin-metadata.c
index 82b82c318f14..afd84cacca4b 100644
--- a/drivers/md/dm-thin-metadata.c
+++ b/drivers/md/dm-thin-metadata.c
@@ -681,10 +681,11 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
         bm = dm_block_manager_create(bdev, THIN_METADATA_BLOCK_SIZE,
                                      THIN_METADATA_CACHE_SIZE,
                                      THIN_MAX_CONCURRENT_LOCKS);
-        if (!bm) {
+        if (IS_ERR(bm)) {
+                r = PTR_ERR(bm);
                 DMERR("could not create block manager");
                 kfree(pmd);
-                return ERR_PTR(-ENOMEM);
+                return ERR_PTR(r);
         }
 
         r = superblock_all_zeroes(bm, &create);
@@ -694,7 +695,6 @@ struct dm_pool_metadata *dm_pool_metadata_open(struct block_device *bdev,
                 return ERR_PTR(r);
         }
 
-
         r = init_pmd(pmd, bm, 0, create);
         if (r) {
                 dm_block_manager_destroy(bm);