[ofa-general] [PATCH V4] infiniband/core: Enable loopback of DR SMP responses from userspace

[swelch at systemfabricworks.com]

  This patch [v4] replaces the [v3] patch; it's identicial other than
  the patch description has been updated to put back in the detailed
  patch description absent from the [v3] patch.

  The local loopback of an outgoing DR SMP response is limited to those
  that originate at the driver specific SMA implementation during the
  driver specific process_mad() function.  This patch enables a
  returning DR SMP originating in userspace (or elsewhere) to be
  delivered to the local managment stack.  In this specific  case
  the driver process_mad() function does not consume or process
  the MAD, so a reponse mad has not be created and the original
  MAD must manually be copied to the MAD buffer that is to be handed
  off to the local agent.

  For consistent bahavior on top of iPath hardware, a subsequent patch
  to be submitted by Ralph Campbell to update process_mad() return values
  is required.

  Thanks, Steve

Signed-off-by: Steve Welch <swelch at systemfabricworks.com>
---
 drivers/infiniband/core/mad.c |    6 +++---
 drivers/infiniband/core/smi.h |   18 +++++++++++++++++-
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/core/mad.c b/drivers/infiniband/core/mad.c
index 6f42877..98148d6 100644
--- a/drivers/infiniband/core/mad.c
+++ b/drivers/infiniband/core/mad.c
@@ -701,7 +701,8 @@ static int handle_outgoing_dr_smp(struct ib_mad_agent_private *mad_agent_priv,
 	}
 
 	/* 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_returning_smp(smp, device) == IB_SMI_DISCARD)
 		goto out;
 
 	local = kmalloc(sizeof *local, GFP_ATOMIC);
@@ -752,8 +753,7 @@ static int handle_outgoing_dr_smp(struct ib_mad_agent_private *mad_agent_priv,
 		port_priv = ib_get_mad_port(mad_agent_priv->agent.device,
 					    mad_agent_priv->agent.port_num);
 		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));
 			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..aff96ba 100644
--- a/drivers/infiniband/core/smi.h
+++ b/drivers/infiniband/core/smi.h
@@ -59,7 +59,8 @@ extern enum smi_action smi_handle_dr_smp_send(struct ib_smp *smp,
 					      u8 node_type, int port_num);
 
 /*
- * Return 1 if the SMP should be handled by the local SMA/SM via process_mad
+ * Return IB_SMI_HANDLE if the SMP should be handled by the local SMA/SM
+ * via process_mad
  */
 static inline enum smi_action smi_check_local_smp(struct ib_smp *smp,
 						  struct ib_device *device)
@@ -71,4 +72,19 @@ 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 IB_SMI_HANDLE if the SMP should be handled by the local SMA/SM
+ * via process_mad
+ */
+static inline enum smi_action smi_check_local_returning_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);
+}
+
 #endif	/* __SMI_H_ */