dm cache: lift common migration preparation code to alloc_migration()

Signed-off-by: Mike Snitzer <snitzer@redhat.com>

1 files changed, 7 insertions, 10 deletions

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index f81daf8638a4..cf23a14f9c6a 100644
--- a/drivers/md/dm-cache-target.c
+++ b/drivers/md/dm-cache-target.c
@@ -551,10 +551,13 @@ static struct dm_cache_migration *alloc_migration(struct cache *cache)
         struct dm_cache_migration *mg;
 
         mg = mempool_alloc(cache->migration_pool, GFP_NOWAIT);
-        if (mg) {
-                mg->cache = cache;
-                atomic_inc(&mg->cache->nr_allocated_migrations);
-        }
+        if (!mg)
+                return NULL;
+
+        memset(mg, 0, sizeof(*mg));
+
+        mg->cache = cache;
+        atomic_inc(&cache->nr_allocated_migrations);
 
         return mg;
 }
@@ -1542,9 +1545,6 @@ static int mg_start(struct cache *cache, struct policy_work *op, struct bio *bio
                 return -ENOMEM;
         }
 
-        memset(mg, 0, sizeof(*mg));
-
-        mg->cache = cache;
         mg->op = op;
         mg->overwrite_bio = bio;
 
@@ -1678,9 +1678,6 @@ static int invalidate_start(struct cache *cache, dm_cblock_t cblock,
                 return -ENOMEM;
         }
 
-        memset(mg, 0, sizeof(*mg));
-
-        mg->cache = cache;
         mg->overwrite_bio = bio;
         mg->invalidate_cblock = cblock;
         mg->invalidate_oblock = oblock;