Re: [PATCH 2/2] blk-ioprio: remove per-disk structure

[Yu Kuai]

Hi,

在 2024/07/12 13:22, Christoph Hellwig 写道:
> On Fri, Jul 12, 2024 at 09:10:30AM +0800, Yu Kuai wrote:
> > > As one can see in the output of git grep -nHEB1 '>pd_(alloc|free)_fn\(',
> > > none of the pd_alloc_fn / pd_free_fn callers checks whether or not these
> > > pointers are NULL. Hence my question why this patch does not trigger any
> > > NULL pointer dereferences?
> >
> > Because the blkcg_deactivate_policy() is removed as well, there are no
> > callers now... blkcg_policy_register() is still called to make sure
> > cpd_(alloc|free)_fn will still be called.
>
> Can you throw in a patch documenting this?  Any maybe add a check
> that pd_alloc_fn / pd_free_fn exist in blkcg_activate_policy and
> WARN and return an error otherwise?

Of course, I realized now that just mention don't activate the policy
from commit message is too little explanation.

Thanks,
Kuai

> .