blkcg: make ->cpd_init_fn() optional

For policies which can do enough initialization from ->cpd_alloc_fn(),
make ->cpd_init_fn() optional.

Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 6a82ca3..78ccbdc 100644 (file)
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1475,7 +1475,8 @@ int blkcg_policy_register(struct blkcg_policy *pol)
                        blkcg->cpd[pol->plid] = cpd;
                        cpd->blkcg = blkcg;
                        cpd->plid = pol->plid;
-                       pol->cpd_init_fn(cpd);
+                       if (pol->cpd_init_fn)
+                               pol->cpd_init_fn(cpd);
                }
        }