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

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

diff --git a/drivers/md/dm-cache-target.c b/drivers/md/dm-cache-target.c
index f81daf8638a47e2f75e328147cf84b8e32343534..cf23a14f9c6a6572955746f040802dcfd34d801d 100644 (file)
--- 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;