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Date:   Tue, 1 Nov 2022 18:27:20 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Jinlong Chen <nickyc975@zju.edu.cn>
Cc:     axboe@kernel.dk, hch@lst.de, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/4] blk-mq: update comment for
 blk_mq_quiesce_queue_nowait()
Message-ID: <20221101172720.GA20526@lst.de>
References: <cover.1667314759.git.nickyc975@zju.edu.cn> <489a9322eed1f95f8770752cc715084f1fa961d3.1667314759.git.nickyc975@zju.edu.cn>
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On Tue, Nov 01, 2022 at 11:11:34PM +0800, Jinlong Chen wrote:
> blk_mq_quiesce_queue_nowait() is now reasonably used by scsi_host_block()
> to avoid calling synchronize_rcu() for each LUN. We should not consider to
> remove it.

I strongly disagree about this being a reasonable use.  What SCSI did
there is a horrible hack that should have never been merged.  The
right thing to do is the per-tag_set quiesce that we've been working
on.