ib_mad: incoming sminfo SMPs gets discarded if no process_mad function is registered

The process_mad function is an optional IB driver entry point
allows a driver to intercept or modify MAD traffic.

This fix allows MAD traffic to flow down to the device also
when MAD traffic is completely handled by the device and
no process_mad function is provided.

Orabug: 20930262

Signed-off-by: Knut Omang <[email protected]>
Signed-off-by: Mukesh Kacker <[email protected]>

Author: Dag Moxnes

drivers/infiniband/core/mad.c

@@ -762,6 +762,9 @@ static int handle_outgoing_dr_smp(struct ib_mad_agent_private *mad_agent_priv,
 		goto out;
 	}
 
+	if (!device->process_mad)
+		goto out;
+
 	/* Check to post send on QP or process locally */
 	if (smi_check_local_smp(smp, device) == IB_SMI_DISCARD &&
 	    smi_check_local_returning_smp(smp, device) == IB_SMI_DISCARD)

drivers/infiniband/core/smi.h

@@ -67,8 +67,7 @@ static inline enum smi_action smi_check_local_smp(struct ib_smp *smp,
 {
 	/* C14-9:3 -- We're at the end of the DR segment of path */
 	/* C14-9:4 -- Hop Pointer = Hop Count + 1 -> give to SMA/SM */
-	return ((device->process_mad &&
-		!ib_get_smp_direction(smp) &&
+	return ((!ib_get_smp_direction(smp) &&
 		(smp->hop_ptr == smp->hop_cnt + 1)) ?
 		IB_SMI_HANDLE : IB_SMI_DISCARD);
 }
@@ -82,8 +81,7 @@ static inline enum smi_action smi_check_local_returning_smp(struct ib_smp *smp,
 {
 	/* 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) &&
+	return ((ib_get_smp_direction(smp) &&
 		!smp->hop_ptr) ? IB_SMI_HANDLE : IB_SMI_DISCARD);
 }