IB/mthca: Fix dispatch of IB_EVENT_LID_CHANGE event

When snooping a PortInfo MAD, its client_reregister bit is checked.
If the bit is ON then a CLIENT_REREGISTER event is dispatched,
otherwise a LID_CHANGE event is dispatched.  This way of decision
ignores the cases where the MAD changes the LID along with an
instruction to reregister (so a necessary LID_CHANGE event won't be
dispatched) or the MAD is neither of these (and an unnecessary
LID_CHANGE event will be dispatched).

This causes problems at least with IPoIB, which will do a "light"
flush on reregister, rather than the "heavy" flush required due to a
LID change.

Fix this by dispatching a CLIENT_REREGISTER event if the
client_reregister bit is set, but also compare the LID in the MAD to
the current LID.  If and only if they are not identical then a
LID_CHANGE event is dispatched.

Signed-off-by: Moni Shoua <monis@voltaire.com>
Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>
Signed-off-by: Yossi Etigin <yosefe@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

diff --git a/drivers/infiniband/hw/mthca/mthca_mad.c b/drivers/infiniband/hw/mthca/mthca_mad.c
index 6404495..5648659 100644 (file)
--- a/drivers/infiniband/hw/mthca/mthca_mad.c
+++ b/drivers/infiniband/hw/mthca/mthca_mad.c
@@ -104,7 +104,8 @@ static void update_sm_ah(struct mthca_dev *dev,
  */
 static void smp_snoop(struct ib_device *ibdev,
                      u8 port_num,
-                     struct ib_mad *mad)
+                     struct ib_mad *mad,
+                     u16 prev_lid)
 {
        struct ib_event event;
 
@@ -114,6 +115,7 @@ static void smp_snoop(struct ib_device *ibdev,
                if (mad->mad_hdr.attr_id == IB_SMP_ATTR_PORT_INFO) {
                        struct ib_port_info *pinfo =
                                (struct ib_port_info *) ((struct ib_smp *) mad)->data;
+                       u16 lid = be16_to_cpu(pinfo->lid);
 
                        mthca_update_rate(to_mdev(ibdev), port_num);
                        update_sm_ah(to_mdev(ibdev), port_num,
@@ -123,12 +125,15 @@ static void smp_snoop(struct ib_device *ibdev,
                        event.device           = ibdev;
                        event.element.port_num = port_num;
 
-                       if (pinfo->clientrereg_resv_subnetto & 0x80)
+                       if (pinfo->clientrereg_resv_subnetto & 0x80) {
                                event.event    = IB_EVENT_CLIENT_REREGISTER;
-                       else
-                               event.event    = IB_EVENT_LID_CHANGE;
+                               ib_dispatch_event(&event);
+                       }
 
-                       ib_dispatch_event(&event);
+                       if (prev_lid != lid) {
+                               event.event    = IB_EVENT_LID_CHANGE;
+                               ib_dispatch_event(&event);
+                       }
                }
 
                if (mad->mad_hdr.attr_id == IB_SMP_ATTR_PKEY_TABLE) {
@@ -196,6 +201,8 @@ int mthca_process_mad(struct ib_device *ibdev,
        int err;
        u8 status;
        u16 slid = in_wc ? in_wc->slid : be16_to_cpu(IB_LID_PERMISSIVE);
+       u16 prev_lid = 0;
+       struct ib_port_attr pattr;
 
        /* Forward locally generated traps to the SM */
        if (in_mad->mad_hdr.method == IB_MGMT_METHOD_TRAP &&
@@ -233,6 +240,12 @@ int mthca_process_mad(struct ib_device *ibdev,
                        return IB_MAD_RESULT_SUCCESS;
        } else
                return IB_MAD_RESULT_SUCCESS;
+       if ((in_mad->mad_hdr.mgmt_class == IB_MGMT_CLASS_SUBN_LID_ROUTED ||
+            in_mad->mad_hdr.mgmt_class == IB_MGMT_CLASS_SUBN_DIRECTED_ROUTE) &&
+           in_mad->mad_hdr.method == IB_MGMT_METHOD_SET &&
+           in_mad->mad_hdr.attr_id == IB_SMP_ATTR_PORT_INFO &&
+           !ib_query_port(ibdev, port_num, &pattr))
+               prev_lid = pattr.lid;
 
        err = mthca_MAD_IFC(to_mdev(ibdev),
                            mad_flags & IB_MAD_IGNORE_MKEY,
@@ -252,7 +265,7 @@ int mthca_process_mad(struct ib_device *ibdev,
        }
 
        if (!out_mad->mad_hdr.status) {
-               smp_snoop(ibdev, port_num, in_mad);
+               smp_snoop(ibdev, port_num, in_mad, prev_lid);
                node_desc_override(ibdev, out_mad);
        }