Re: [PATCH v2 1/2] blk-iocost: add refcounting for iocg

[Tejun Heo]

Hello,

On Fri, Jan 13, 2023 at 09:10:25AM +0800, Yu Kuai wrote:
> > only activate the policy when the controller is actually enabled. So, idk.
> > What's wrong with synchronizing the two removal paths? blkcg policies are
> > combinations of cgroups and block device configurations, so having exit
> > paths from both sides is kinda natural.
> 
> I still can't figure out how to synchronizing them will a mutex. Maybe
> I'm being foolish...

Hmm... can't you just use e.g. per-bdev mutex which is grabbed by both
blkg_free_workfn() and blkcg_deactivate_policy()?

Thanks.

-- 
tejun