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Message-ID: <4751eb9b-755f-f890-cdda-03abff15e6f4@acm.org>
Date:   Wed, 23 Aug 2023 07:39:39 -0700
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Subject: Re: [PATCH v2 3/6] blk-mq-tag: remove bt_for_each()
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To:     chengming.zhou@linux.dev, axboe@kernel.dk, ming.lei@redhat.com,
        hch@lst.de
Cc:     linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
        zhouchengming@bytedance.com
References: <20230823090441.3986631-1-chengming.zhou@linux.dev>
 <20230823090441.3986631-4-chengming.zhou@linux.dev>
From:   Bart Van Assche <bvanassche@acm.org>
In-Reply-To: <20230823090441.3986631-4-chengming.zhou@linux.dev>
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On 8/23/23 02:04, chengming.zhou@linux.dev wrote:
> Change the only user of bt_for_each() to use the introduced function
> __blk_mq_tagset_busy_iter() to specify queue filter when iterating.
> 
> Since blk_mq_queue_tag_busy_iter() is only used to iterate over started
> requests, __blk_mq_tagset_busy_iter() already have BT_TAG_ITER_STARTED
> filter to iterate over started requests only, there should be no
> problem.
> 
> Only one potential disadvantage I can see is that we lost the
> blk_mq_hw_queue_mapped() filter, which maybe not happen for now.
> Unmapped hctx was used to dynamically map or unmap when CPU hotplug,
> but we don't do this anymore, we always map all possible CPUs now.
> So it seems unmapped hctx may only happen if something wrong with
> driver's tagset map settings.

Reviewed-by: Bart Van Assche <bvanassche@acm.org>