Re: [PATCH] scsi: core: cleanup request queue before releasing gendisk

Christoph Hellwig
2021-09-17T12:37:32Z

On Fri, Sep 17, 2021 at 04:32:15PM +0800, Ming Lei wrote:
> > Is it? For the typical case the second free in blk_cleanp_queue will
> > be bsically free because there is no pending I/O. The only case
> > where that matters if if there is pending passthrough I/O again,
> > which can only happen with SCSI, and even there is highly unusual.
>
> RCU grace period is involved in blk_freeze_queue().

where?

> One way you can
> avoid it is to keep the percpu ref at atomic mode when running
> blk_mq_unfreeze_queue() in del_gendisk().
>
>
>
> Thanks,
> Ming
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