[ofa-general] [PATCH] infiniband: add userspace support for invalidate stag

[Roland Dreier]

A few general things:
 - please always submit patches with a changelog entry and
   Signed-off-by: line
 - please send patches in logical chunks.  Usually I'm complaining
   about people combining unrelated things into one patch, but in this
   case I think you divided the patch up too much -- rather than 5
   patches, this should probably be one kernel patch and one userspace
   patch.
 - please make libibverbs patches apply to the libibverbs git tree
   with -p1.  You seem to have generated patches against an OFED package.

OK, with that out of the way, I think there are still some issues to
sort out with how to handle send with invalidate from userspace.
These patches don't address the case of new userspace with
send-with-invalidate support talking to an unpatched kernel -- it
seems that send-with-invalidate would be silently turned into a plain
send request, which is not a very good failure mode.

I don't know what the right solution is yet -- a kernel ABI bump for
this one case (send with invalidate support for userspace drivers that
don't do kernel bypass == amso1100) is ugly.  Maybe we also need a
device capabilities bit that says whether send-with-invalidate is
supported?

 - R.