RE: [WTF] utterly tasteless ABI in hfi1 (around ->write()/->write_iter())

[Dalessandro, Dennis]

Just wanted to re-send so it gets picked up by the lists. I was using a different
server than usual and vger did not like it. Hopefully this attempt fares better.
Sorry for the extra noise.

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 On Wed, Mar 16, 2016 at 11:46:31AM -0400, Doug Ledford wrote:
>Intel: For your own sake's you might want to consider doing something
>simple such as using two files, one for regular commands and one for
>SDMA commands, and modifying both the hfi1 and libpsm2 code bases.  I
>don't care, and I wouldn't force you to do it, but I've made my argument
>to Al and he appears to be running it up the tree, so it might be
>easiest to capitulate.

This should be doable. We could have multiple files and have each implement only
the appropriate handler, write() for control and writev() for data. Another
option we are considering is combine the struct used for regular commands and
the one for SDMA commands into a union in a structure that includes some magic
value that tells us how to interpret the payload. This way whether it's write()
or writev() won't matter we'll know how to handle it. We'll start with fixing
hfi1 first and go from there.

-Denny