[openib-general] Re: Dual Sided RMPP Support as well as OpenSM Implications

[Roland Dreier]

    Hal> It certainly is more deterministic if there is an ABI version
    Hal> change in that the errors can be disambiguated better but is
    Hal> it required if an ioctl is added or alternatively
    Hal> rmpp_version bit is "stolen" ?

I'm pretty confused.  What would the ioctl do?  Return a bit saying
whether or not dual-sided RMPP is supported?  What would happen if an
old app that didn't know about dual-sided RMPP ran and didn't perform
the ioctl?

I guess this isn't really an ABI change -- old binaries continue to
run as long as they don't try dual-sided RMPP (which doesn't work now).
So maybe the answer is /sys/class/infiniband_mad/dual_sided_rmpp?

An ioctl for something that is not attached to a file descriptor isn't
really the right thing.

 - R.