[ofa-general] [PATCH] infiniband/core: Enable loopback of DR SMP responses from userspace

[Hal Rosenstock]

On 9/5/07, Steve Welch <swelch at systemfabricworks.com> wrote:
> > >        /* Check to post send on QP or process locally */
> > > -       if (smi_check_local_smp(smp, device) == IB_SMI_DISCARD)
> > > +       if (smi_check_local_smp(smp, device) == IB_SMI_DISCARD &&
> > > +           smi_check_local_resp_smp(smp, device) == IB_SMI_DISCARD)
> > >                goto out;
> > >
> > >        local = kmalloc(sizeof *local, GFP_ATOMIC);
> > > @@ -754,6 +755,7 @@ static int handle_outgoing_dr_smp(struct
> > ib_mad_agent_private *mad_agent_priv,
> > >                if (port_priv) {
> > >                        mad_priv->mad.mad.mad_hdr.tid =
> > >                                ((struct ib_mad *)smp)->mad_hdr.tid;
> > > +                       memcpy(&mad_priv->mad.mad, smp, sizeof(struct
> > ib_mad));
> >
> > Is this copy only needed in the (new) returning direction case ?
>
> No, it is needed whether the SMP is a request or response.
>
> >
> > >                        recv_mad_agent = find_mad_agent(port_priv,
> > >                                                        &mad_priv-
> > >mad.mad);
> > >                }
> > > diff --git a/drivers/infiniband/core/smi.h
> > b/drivers/infiniband/core/smi.h
> > > index 1cfc298..d96fc8e 100644
> > > --- a/drivers/infiniband/core/smi.h
> > > +++ b/drivers/infiniband/core/smi.h
> > > @@ -71,4 +71,18 @@ static inline enum smi_action
> > smi_check_local_smp(struct ib_smp *smp,
> > >                (smp->hop_ptr == smp->hop_cnt + 1)) ?
> > >                IB_SMI_HANDLE : IB_SMI_DISCARD);
> > >  }
> > > +
> > > +/*
> > > + * Return 1 if the SMP response should be handled by the local
> > management stack
> > > + */
> > > +static inline enum smi_action smi_check_local_resp_smp(struct ib_smp
> > *smp,
> > > +                                                      struct ib_device
> > *device)
> > > +{
> > > +       /* C14-13:3 -- We're at the end of the DR segment of path */
> > > +       /* C14-13:4 -- Hop Pointer == 0 -> give to SM */
> > > +       return ((device->process_mad &&
> > > +               ib_get_smp_direction(smp) &&
> > > +               !smp->hop_ptr) ? IB_SMI_HANDLE : IB_SMI_DISCARD);
> > > +}
> > > +
> >
> > I think this routine and the existing one could be better named:
> > smi_check_local_outgoing/returning_smp.
> >
>
> Possibly, but the SMP does originate in both cases from a local mad send
> operation.  In one case sending the request and in the other sending the
> response; in both cases they are locally handled.

Aren't they more appropriately termed outgoing and returning rather
than request/response ? Guess it ends up being the same since in
practice Traps and TrapRepresses are only LID routed but there is
nothing in the spec that precludes them from being direct routed.

-- Hal

>
> Steve
>
> > -- Hal
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