From: Christoph Hellwig <hch@lst.de>
To: Ming Lei <ming.lei@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH] block: don't protect submit_bio_checks by q_usage_counter
Date: Mon, 10 Jan 2022 17:49:09 +0100 [thread overview]
Message-ID: <20220110164909.GA7372@lst.de> (raw)
In-Reply-To: <20220104134223.590803-1-ming.lei@redhat.com>
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.
next prev parent reply other threads:[~2022-01-10 16:49 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-01-04 13:42 [PATCH] block: don't protect submit_bio_checks by q_usage_counter Ming Lei
2022-01-10 0:05 ` Ming Lei
2022-01-10 1:56 ` Jens Axboe
2022-01-10 1:59 ` Jens Axboe
2022-01-10 16:49 ` Christoph Hellwig [this message]
2022-01-11 1:16 ` Ming Lei
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