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Date:   Sun, 14 Mar 2021 09:14:41 +0000
From:   Christoph Hellwig <hch@infradead.org>
To:     Mike Snitzer <snitzer@redhat.com>
Cc:     Sergei Shtepa <sergei.shtepa@veeam.com>,
        Christoph Hellwig <hch@infradead.org>,
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        dm-devel@redhat.com, linux-block@vger.kernel.org,
        linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
        pavel.tide@veeam.com
Subject: Re: [PATCH v7 1/3] block: add blk_mq_is_queue_frozen()
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On Fri, Mar 12, 2021 at 02:06:41PM -0500, Mike Snitzer wrote:
> This is returning a frozen state that is immediately stale.  I don't
> think any code calling this is providing the guarantees you think it
> does due to the racey nature of this state once the mutex is dropped.

The code only uses it for asserts in the form of WARN_ONs.