Messages in this thread | | | Date | Sat, 8 Feb 2014 08:55:07 +0800 | From | Shaohua Li <> | Subject | Re: [PATCH 1/1] block: rework flush sequencing for blk-mq |
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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
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