From: Christoph Hellwig <hch@lst.de>
To: Bart Van Assche <bvanassche@acm.org>
Cc: Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, Jaegeuk Kim <jaegeuk@kernel.org>,
Ming Lei <ming.lei@redhat.com>,
Damien Le Moal <damien.lemoal@opensource.wdc.com>,
Johannes Thumshirn <johannes.thumshirn@wdc.com>
Subject: Re: [PATCH v2 3/3] block: Preserve LBA order when requeuing
Date: Thu, 23 Mar 2023 09:19:01 +0100 [thread overview]
Message-ID: <20230323081901.GA21977@lst.de> (raw)
In-Reply-To: <6325fba6-3dac-9391-28ef-177fcae9ad0a@acm.org>
On Tue, Mar 21, 2023 at 07:46:51AM -0700, Bart Van Assche wrote:
> On 3/20/23 22:58, Christoph Hellwig wrote:
>> On Mon, Mar 20, 2023 at 04:49:05PM -0700, Bart Van Assche wrote:
>>> When requeuing a request to a zoned block device, preserve the LBA order
>>> per zone.
>>
>> What causes this requeue?
>
> Hi Christoph,
>
> Two examples of why the SCSI core can decide to requeue a command are a
> retryable unit attention or ufshcd_queuecommand() returning
> SCSI_MLQUEUE_HOST_BUSY. For example, ufshcd_queuecommand() returns
> SCSI_MLQUEUE_HOST_BUSY while clock scaling is in progress (changing the
> frequency of the link between host controller and UFS device).
None of these should happen as the upper layers enforce a per-zone
queue depth of 1.
prev parent reply other threads:[~2023-03-23 8:19 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-20 23:49 [PATCH v2 0/3] Submit zoned requests in LBA order per zone Bart Van Assche
2023-03-20 23:49 ` [PATCH v2 1/3] block: Split blk_recalc_rq_segments() Bart Van Assche
2023-03-20 23:49 ` [PATCH v2 2/3] block: Split and submit bios in LBA order Bart Van Assche
2023-03-21 6:03 ` Christoph Hellwig
2023-03-21 6:05 ` Christoph Hellwig
2023-03-21 18:44 ` Bart Van Assche
2023-03-23 8:22 ` Christoph Hellwig
2023-03-20 23:49 ` [PATCH v2 3/3] block: Preserve LBA order when requeuing Bart Van Assche
2023-03-21 5:58 ` Christoph Hellwig
2023-03-21 14:46 ` Bart Van Assche
2023-03-23 8:19 ` Christoph Hellwig [this message]
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