On Tue, Jan 04, 2022 at 09:42:23PM +0800, Ming Lei wrote:
> Commit cc9c884dd7f4 ("block: call submit_bio_checks under q_usage_counter")
> uses q_usage_counter to protect submit_bio_checks for avoiding IO after
> disk is deleted by del_gendisk().
>
> Turns out the protection isn't necessary, because once
> blk_mq_freeze_queue_wait() in del_gendisk() returns:
>
> 1) all in-flight IO has been done
Only for blk-mq drivers.
So I don't think this is actually safe.
Sorry for the late reply, last week was still holiday time here.
