Re: [PATCH 01/10] blk-cgroup: use cgroup lock and rcu to protect iterating blkcg blkgs

[Yu Kuai]

Hi,

在 2025/9/25 23:57, Bart Van Assche 写道:
> On 9/25/25 1:15 AM, Yu Kuai wrote:
> > It's safe to iterate blkgs with cgroup lock or rcu lock held, prevent
> > nested queue_lock under rcu lock, and prepare to convert protecting
> > blkcg with blkcg_mutex instead of queuelock.
>
> Iterating blkgs without holding q->queue_lock is safe but accessing the
> blkg members without holding that lock is not safe since q->queue_lock
> is acquired by all code that modifies blkg members. Should perhaps a new
> spinlock be introduced to serialize blkg modifications?
No need for a new lock, I think blkcg->lock can do that.

Thanks,
Kuai

> Thanks,
>
> Bart.