[PATCH v3] don't forget to call pd_online_fn when activate policy

[PATCH v3] don't forget to call pd_online_fn when activate policy

[Zhou Chengming]

When we activate policy on the request_queue, we will create policy_date
for all the existing blkgs of the request_queue, so we should call
pd_init_fn() and pd_online_fn() on these newly created policy_data.

Signed-off-by: Zhou Chengming <zhouchengming1@huawei.com>
---
 block/blk-cgroup.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 8ba0af7..1eba1d2 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -1254,6 +1254,12 @@ int blkcg_activate_policy(struct request_queue *q,
 		pd->plid = pol->plid;
 		if (pol->pd_init_fn)
 			pol->pd_init_fn(pd);
+
+		if (pol->pd_online_fn) {
+			spin_lock(&blkg->blkcg->lock);
+			pol->pd_online_fn(pd);
+			spin_unlock(&blkg->blkcg->lock);
+		}
 	}
 
 	__set_bit(pol->plid, q->blkcg_pols);
-- 
1.8.3.1

Re: [PATCH v3] don't forget to call pd_online_fn when activate policy

[Jens Axboe]

On 03/10/2017 08:46 PM, Zhou Chengming wrote:
> When we activate policy on the request_queue, we will create policy_date
> for all the existing blkgs of the request_queue, so we should call
> pd_init_fn() and pd_online_fn() on these newly created policy_data.

I'm not looking at this until you tell me that you have runtime
tested it. I'm assuming you originally ran into some issue
with the lack of calling pd_online_fn?

-- 
Jens Axboe