[PATCH 1/7] nvme-fabrics: Add FC transport FC-NVME definitions

[Hannes Reinecke]

On 10/06/2016 01:21 AM, James Smart wrote:
>
>
> On 10/4/2016 6:58 AM, Christoph Hellwig wrote:
>> On Tue, Oct 04, 2016 at 09:32:39AM +0200, Hannes Reinecke wrote:
>>> I would have loved to use the SCSI FC headers here; eg the definitions
>>> for FC-LS are most definitely duplicated.
>>> But until we've sorted that one out:
>> I remember we discussed this before, but I've forgot the outcome on
>> why this needed to be separate.  IIRC it was just a timing issue,
>> but now that we've just missed the previous merge window we should
>> have plenty of time to sort that out properly.  Correct me if I'm wrong.
>
> I looked at the include/uapi/scsi/fc headers.
>
> The only field that should be there is the addition of the NVME type code.
>
> The LS's things - although they look very similar to ELS things, they
> aren't the same thing.  The LS items are specific to type code 0x28 - a
> value in the FC frame header, while ELS's are type code 0x01 in the
> frame header.  The content is specific to the type code.  True, some of
> the formats, like xx_ACC, and a little of xx_RJT are similar (on purpose
> by the fc-nvme group) - there's no real reason that they had to be, so
> actually forcing things into using the other's structures isn't a good
> idea in case things change.
>
> After looking at it - the only thing that I was wondering is whether the
> fc-nvme definitions should be in "include/linux/nvme-fc.h" as it's
> specific to nvme fabrics or whether they should be in
> "include/uapi/scsi/fc/fc-nvme.h" - so it's in a location where all other
> fc'isms are at. Even though NVME and the scsi directory name doesn't
> seem to make sense.
>
Ah, right. Thanks for the explanation.
I wasn't aware that the FC-LS codes are in fact type dependent.
But if they are then it indeed makes not much sense to have them merged.

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      zSeries & Storage
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