IPoIB: Refresh paths instead of flushing them on SM change events

The patch tries to solve the problem of device going down and paths being
flushed on an SM change event. The method is to mark the paths as candidates for
refresh (by setting the new valid flag to 0), and wait for an ARP
probe a new path record query.

The solution requires a different and less intrusive handling of SM
change event. For that, the second argument of the flush function
changes its meaning from a boolean flag to a level.  In most cases, SM
failover doesn't cause LID change so traffic won't stop.  In the rare
cases of LID change, the remote host (the one that hadn't changed its
LID) will lose connectivity until paths are refreshed. This is no
worse than the current state.  In fact, preventing the device from
going down saves packets that otherwise would be lost.

Signed-off-by: Moni Levy <monil@voltaire.com>
Signed-off-by: Moni Shoua <monis@voltaire.com>
Signed-off-by: Roland Dreier <rolandd@cisco.com>

1 files changed, 10 insertions, 8 deletions

diff --git a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
index 7b8fa36f509..96f9aa79cbb 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_verbs.c
@@ -290,15 +290,17 @@ void ipoib_event(struct ib_event_handler *handler,
 	if (record->element.port_num != priv->port)
 		return;
 
-	if (record->event == IB_EVENT_PORT_ERR    ||
-	    record->event == IB_EVENT_PORT_ACTIVE ||
-	    record->event == IB_EVENT_LID_CHANGE  ||
-	    record->event == IB_EVENT_SM_CHANGE   ||
+	ipoib_dbg(priv, "Event %d on device %s port %d\n", record->event,
+		  record->device->name, record->element.port_num);
+
+	if (record->event == IB_EVENT_SM_CHANGE ||
 	    record->event == IB_EVENT_CLIENT_REREGISTER) {
-		ipoib_dbg(priv, "Port state change event\n");
-		queue_work(ipoib_workqueue, &priv->flush_task);
+		queue_work(ipoib_workqueue, &priv->flush_light);
+	} else if (record->event == IB_EVENT_PORT_ERR ||
+		   record->event == IB_EVENT_PORT_ACTIVE ||
+		   record->event == IB_EVENT_LID_CHANGE) {
+		queue_work(ipoib_workqueue, &priv->flush_normal);
 	} else if (record->event == IB_EVENT_PKEY_CHANGE) {
-		ipoib_dbg(priv, "P_Key change event on port:%d\n", priv->port);
-		queue_work(ipoib_workqueue, &priv->pkey_event_task);
+		queue_work(ipoib_workqueue, &priv->flush_heavy);
 	}
 }