[ofa-general] [PATCH v2] ipoib: fix loss of connectivity after bonding failover on both sides

[Yossi Etigin]

Fix bonding failover in the case poth peers have failover and gratuitous arp
is lost.
In that case, ipoib sender side will create ipoib_neigh and issue a path request
with the old gid first. When skb->dst->neighbour->ha changes due to arp refresh,
ipoib_neigh will not be added to the path->list of the path of the new mgid,
because ipoib_neigh already exists. It will not have an ah either, because of
sender-side failover. Therefore, it will not get an ah when the path is resolved.

The solution here is to compare gids even if neigh->ah is invalid. Comparing with
an uninitialized value of neigh->dgid is not worse than the situation before the
patch.

Signed-off-by: Moni Shoua <monis at voltaire.com>
Signed-off-by: Yossi Etigin <yosefe at voltaire.com>
---

Changes from v1:
Remove unneeded changelog clause and style fix.

Fix bugzilla 1286.

 drivers/infiniband/ulp/ipoib/ipoib_main.c |   38 +++++++++++++++---------------
 1 file changed, 19 insertions(+), 19 deletions(-)

Index: b/drivers/infiniband/ulp/ipoib/ipoib_main.c
===================================================================
--- a/drivers/infiniband/ulp/ipoib/ipoib_main.c	2009-01-07 21:47:23.000000000 +0200
+++ b/drivers/infiniband/ulp/ipoib/ipoib_main.c	2009-01-08 18:54:33.000000000 +0200
@@ -687,26 +687,26 @@ static int ipoib_start_xmit(struct sk_bu
 
 		neigh = *to_ipoib_neigh(skb->dst->neighbour);
 
-		if (neigh->ah)
-			if (unlikely((memcmp(&neigh->dgid.raw,
-					    skb->dst->neighbour->ha + 4,
-					    sizeof(union ib_gid))) ||
-					 (neigh->dev != dev))) {
-				spin_lock_irqsave(&priv->lock, flags);
-				/*
-				 * It's safe to call ipoib_put_ah() inside
-				 * priv->lock here, because we know that
-				 * path->ah will always hold one more reference,
-				 * so ipoib_put_ah() will never do more than
-				 * decrement the ref count.
-				 */
+		if (unlikely((memcmp(&neigh->dgid.raw,
+				     skb->dst->neighbour->ha + 4,
+				     sizeof(union ib_gid))) ||
+			     (neigh->dev != dev))) {
+			spin_lock_irqsave(&priv->lock, flags);
+			/*
+			 * It's safe to call ipoib_put_ah() inside
+			 * priv->lock here, because we know that
+			 * path->ah will always hold one more reference,
+			 * so ipoib_put_ah() will never do more than
+			 * decrement the ref count.
+			 */
+			if (neigh->ah)
 				ipoib_put_ah(neigh->ah);
-				list_del(&neigh->list);
-				ipoib_neigh_free(dev, neigh);
-				spin_unlock_irqrestore(&priv->lock, flags);
-				ipoib_path_lookup(skb, dev);
-				return NETDEV_TX_OK;
-			}
+			list_del(&neigh->list);
+			ipoib_neigh_free(dev, neigh);
+			spin_unlock_irqrestore(&priv->lock, flags);
+			ipoib_path_lookup(skb, dev);
+			return NETDEV_TX_OK;
+		}
 
 		if (ipoib_cm_get(neigh)) {
 			if (ipoib_cm_up(neigh)) {
-- 
--Yossi