[openib-general] [RFC] [PATCHv2] mad: Add RMPP support foradditional management classes which support it

[Hal Rosenstock]

On Fri, 2006-03-17 at 13:00, Sean Hefty wrote:
> >-static int data_offset(u8 mgmt_class)
> >+int ib_get_rmpp_data_offset(u8 mgmt_class)
> > {
> > 	if (mgmt_class == IB_MGMT_CLASS_SUBN_ADM)
> > 		return IB_MGMT_SA_HDR;
> >+	else if ((mgmt_class == IB_MGMT_CLASS_DEVICE_MGMT) ||
> >+		 (mgmt_class == IB_MGMT_CLASS_DEVICE_ADM) ||
> >+		 (mgmt_class == IB_MGMT_CLASS_BIS))
> >+		return IB_MGMT_DEVICE_HDR;
> > 	else if ((mgmt_class >= IB_MGMT_CLASS_VENDOR_RANGE2_START) &&
> > 		 (mgmt_class <= IB_MGMT_CLASS_VENDOR_RANGE2_END))
> > 		return IB_MGMT_VENDOR_HDR;
> > 	else
> > 		return IB_MGMT_RMPP_HDR;
> > }
> >+EXPORT_SYMBOL(ib_get_rmpp_data_offset);
> 
> Is the base RMPP header (return value of IB_MGMT_RMPP_HDR) ever actually used by
> any class?

With no class specific data ? I think that's possible but I don't think
any classes do this.

> Maybe we should rename this routine to ib_get_mad_data_offset(), and
> let it work on any type of MAD, versus RMPP only.  Then change IB_MGMT_RMPP_HDR
> to IB_MGMT_MAD_HDR.

That can be done but it changes the the places in mad_rmpp.c where
data_offset is called (albeit for classes where RMPP shouldn't be
invoked). I didn't walk the code as to how this could occur...

> >+	hdr_len = ib_get_rmpp_data_offset(rmpp_mad->mad_hdr.mgmt_class);
> >+	if (hdr_len == IB_MGMT_RMPP_HDR) {
> 
> This looks like a check to see if the mgmt_class uses RMPP or not.

Yes, that's what it is doing.

> If we want
> to keep ib_get_rmpp_data_offset as shown above, maybe we can check whether the
> mad_agent uses RMPP, and only call ib_get_rmpp_data_offset if it does.

Yes, that would be clearer.

-- Hal

> - Sean