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SubjectRe: [PATCH 9/9] tcm_qla2xxx: Add special case for COMPARE_AND_WRITE data_direction
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On Tue, 2013-08-20 at 23:37 -0700, Christoph Hellwig wrote:
> On Tue, Aug 20, 2013 at 08:08:00PM +0000, Nicholas A. Bellinger wrote:
> > From: Nicholas Bellinger <nab@daterainc.com>
> >
> > Add a special case for COMPARE_AND_WRITE for the reverse data direction
> > mapping used for pci_map_sg() + friends.
>
> A low level driver is an even worse place to hardcode a specific cdb
> opcode. As written before this should be done by a flag on the command.
>

Which means adding another COMPARE_AND_WRITE specific flag to
se_cmd_flags_Table, as the SCF_COMPARE_AND_WRITE_POST is ony set after
the comparsion of the verify instance data is complete..

Is it really worth having two se_cmd_flags for COMPARE_AND_WRITE..?

> Also it might make sense to lift this helper to get a dma direction from
> a command into common code.
>

Mmm, perhaps. I don't recall of the top of my head why tcm_qla2xxx
actually needed to reverse it's dma direction (I'm sure that Roland
knows, CC'ed), but IIRC it was a tcm_qla2xxx specific thing..?

--nab



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