linux-kernel - Re: [PATCH 7/7] dm: call dm_zone_endio after the target endio callback for zoned devices

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Message-ID: <35293c0c-2d72-c4ee-2296-079d56df7d5b@samsung.com>
Date:   Tue, 10 Jan 2023 10:07:39 +0100
From:   Pankaj Raghav <p.raghav@...sung.com>
To:     Christoph Hellwig <hch@....de>
CC:     <axboe@...nel.dk>, <kernel@...kajraghav.com>,
        <linux-kernel@...r.kernel.org>, <hare@...e.de>,
        <bvanassche@....org>, <snitzer@...nel.org>, <dm-devel@...hat.com>,
        <damien.lemoal@...nsource.wdc.com>,
        <linux-nvme@...ts.infradead.org>, <linux-block@...r.kernel.org>,
        <gost.dev@...sung.com>
Subject: Re: [PATCH 7/7] dm: call dm_zone_endio after the target endio
 callback for zoned devices

On 2023-01-10 07:58, Christoph Hellwig wrote:
> On Fri, Jan 06, 2023 at 09:33:17AM +0100, Pankaj Raghav wrote:
>> dm_zone_endio() updates the bi_sector of orig bio for zoned devices that
>> uses either native append or append emulation, and it is called before the
>> endio of the target. But target endio can still update the clone bio
>> after dm_zone_endio is called, thereby, the orig bio does not contain
>> the updated information anymore.
>>
>> Currently, this is not a problem as the targets that support zoned devices
>> such as dm-zoned, dm-linear, and dm-crypt do not have an endio function,
>> and even if they do (such as dm-flakey), they don't modify the
>> bio->bi_iter.bi_sector of the cloned bio that is used to update the
>> orig_bio's bi_sector in dm_zone_endio function.
>>
>> Call dm_zone_endio for zoned devices after calling the target's endio
>> function.
> 
> This looks sensible, but I fail to see why we need this or how it fits
> into the earlier block layer part of the series.
>


I just extracted the cleanup from my old series. Do you think it is better
to send it as a separate patch instead of adding it along in this series?