Re: [PATCH] blk-cgroup: fix missing pd_online_fn() while activating policy

[Michal Koutný]

Hello.

On Tue, Jan 03, 2023 at 07:28:33PM +0800, Yu Kuai <yukuai1@xxxxxxxxxxxxxxx> wrote:
> If the policy defines pd_online_fn(), it should be called after
> pd_init_fn(), like blkg_create().

Is this based only on code review or has it some negative effects?

I assume this would affect hot-plugged (read after cgroup creation) devices.

I took a cursory look at:

	blkcg_init_disk
	  blkg_create
	    pol->pd_init_fn(blkg->pd[i]);
	    pol->pd_online_fn(blkg->pd[i]);
	  blk_throtl_init
	    blkcg_activate_policy
	      pol->pd_init_fn(blkg->pd[i]);
	      ?? pol->pd_online_fn(blkg->pd[i]);

I.e. the pd_online_fn is already called and pd_init_fn is called 2nd
time? 

Thanks,
Michal

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