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Subject: Re: [PATCH] block: revert pushing the final release of request_queue
 to a workqueue.
From:   "yukuai (C)" <yukuai3@huawei.com>
To:     Bart Van Assche <bvanassche@acm.org>, <axboe@kernel.dk>,
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On 2020/2/7 14:02, yukuai (C) wrote:
> And I do agree that commit 7b36a7189fc3 is the right
> one.

My apologize that this is a mistake. Commit db6d99523560 is the one that
makes it safe to revert commit dc9edc44de6c. Because Commit db6d99523560
remove blk_exit_rl() from blkg_free().

blkg_release
   call_rcu --> can't sleep inside this
     __blkg_release
       blkg_free
         blk_exit_rl
	  blk_put_queue