[ofa-general] [PATCH] ib_ipoib: fix race detaching from mcast group before attaching

[Sean Hefty]

I believe this is a simple fix for the detach before attach race that
Roland pointed out.

I only did some limited testing on my systems, so I can't say that it
will fully fix bug report 400.

Roland, if this looks good to you, let me know and I can push it out to
my git tree.

Signed-off-by: Sean Hefty <sean.hefty at intel.com>
---
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
index bb2e3d5..cd202a0 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_multicast.c
@@ -641,6 +641,9 @@ static int ipoib_mcast_leave(struct net_device *dev, struct ipoib_mcast *mcast)
 	struct ipoib_dev_priv *priv = netdev_priv(dev);
 	int ret = 0;
 
+	if (test_and_clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags))
+		ib_sa_free_multicast(mcast->mc);
+
 	if (test_and_clear_bit(IPOIB_MCAST_FLAG_ATTACHED, &mcast->flags)) {
 		ipoib_dbg_mcast(priv, "leaving MGID " IPOIB_GID_FMT "\n",
 				IPOIB_GID_ARG(mcast->mcmember.mgid));
@@ -652,9 +655,6 @@ static int ipoib_mcast_leave(struct net_device *dev, struct ipoib_mcast *mcast)
 			ipoib_warn(priv, "ipoib_mcast_detach failed (result = %d)\n", ret);
 	}
 
-	if (test_and_clear_bit(IPOIB_MCAST_FLAG_BUSY, &mcast->flags))
-		ib_sa_free_multicast(mcast->mc);
-
 	return 0;
 }