From: Shaohua Li <shli@kernel.org>
To: Christoph Hellwig <hch@infradead.org>
Cc: Jens Axboe <axboe@kernel.dk>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 1/1] block: rework flush sequencing for blk-mq
Date: Sat, 8 Feb 2014 08:55:07 +0800 [thread overview]
Message-ID: <20140208005507.GA1766@kernel.org> (raw)
In-Reply-To: <20140207141915.GA24176@infradead.org>
On Fri, Feb 07, 2014 at 06:19:15AM -0800, Christoph Hellwig wrote:
> On Fri, Feb 07, 2014 at 09:18:27AM +0800, Shaohua Li wrote:
> > Reusing the tag for flush request is considered before. The problem is driver
> > need get a request from a tag, reusing tag breaks this. The possible solution
> > is we provide a blk_mq_tag_to_request, and force driver uses it. And in this
> > function, if tag equals to flush_rq tag, we return flush_request.
>
> If we want to support tag to request reverse mapping we defintively
> need to do this in the core, at which point special casing flush_rq
> there is easy.
>
> Which driver needs the reverse mapping? Neither virtio_blk nor null_blk
> seem to and I've not seen any other conversions submitted except for the
> scsi work.
Yep, none driver needs it. But reverse mapping is the one of the points we use
tag, so better we prepare it.
Thanks,
Shaohua
next prev parent reply other threads:[~2014-02-08 0:55 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-30 13:26 [PATCH 0/1] block: rework flush sequencing for blk-mq Christoph Hellwig
2014-01-30 13:26 ` [PATCH 1/1] " Christoph Hellwig
2014-02-07 1:18 ` Shaohua Li
2014-02-07 14:19 ` Christoph Hellwig
2014-02-08 0:55 ` Shaohua Li [this message]
2014-02-10 10:33 ` Christoph Hellwig
2014-03-07 20:45 ` Jeff Moyer
2014-03-08 15:52 ` Christoph Hellwig
2014-03-08 17:33 ` Mike Snitzer
2014-03-08 19:51 ` Hannes Reinecke
2014-03-08 18:13 ` Mike Snitzer
2014-03-08 21:33 ` Hannes Reinecke
2014-03-08 22:09 ` [PATCH] block: fix q->flush_rq NULL pointer crash on dm-mpath flush Mike Snitzer
2014-03-09 0:24 ` Jens Axboe
2014-03-09 0:57 ` Mike Snitzer
2014-03-09 3:18 ` Jens Axboe
2014-03-09 3:29 ` Mike Snitzer
2014-03-12 10:28 ` [PATCH 1/1] block: rework flush sequencing for blk-mq Christoph Hellwig
2014-03-12 10:50 ` Hannes Reinecke
2014-03-12 10:55 ` Christoph Hellwig
2014-03-12 11:07 ` Hannes Reinecke
2014-03-12 11:00 ` SuSE O_DIRECT|O_NONBLOCK overload Christoph Hellwig
2014-03-13 0:15 ` NeilBrown
2014-03-14 17:46 ` Mike Christie
2014-03-13 16:13 ` [PATCH 1/1] block: rework flush sequencing for blk-mq Mike Snitzer
2014-03-14 9:25 ` Christoph Hellwig
2014-03-14 9:30 ` Hannes Reinecke
2014-03-14 12:44 ` Christoph Hellwig
2014-03-14 9:34 ` Christoph Hellwig
2014-03-14 9:52 ` Hannes Reinecke
2014-03-14 10:58 ` Christoph Hellwig
2014-03-14 11:10 ` Hannes Reinecke
2014-03-14 13:00 ` Mike Snitzer
2014-03-14 13:23 ` Christoph Hellwig
2014-03-14 14:13 ` Mike Snitzer
2014-03-15 13:28 ` scsi_debug and mutipath, was " Christoph Hellwig
2014-03-17 11:55 ` [dm-devel] " Bryn M. Reeves
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