From d25cec00a7bd32c8fb0e455254937f4bcf2ef123 Mon Sep 17 00:00:00 2001
From: Tejun Heo <tj@kernel.org>
Date: Tue, 25 Aug 2020 20:03:05 +0800
Subject: [PATCH] blkcg: make ->cpd_init_fn() optional

mainline inclusion
from mainline-5.4-rc1
commit 86a5bba5c252e90d264c7460e29a0b9e633777e7
category: feature
bugzilla: 38688
CVE: NA

---------------------------

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>
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Hou Tao <houtao1@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
---
 block/blk-cgroup.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 6d218ac90071..8038c2b83f85 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1570,7 +1570,8 @@ 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);
 		}
 	}
 
-- 
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