IB/IPoIB: Disable bottom half when dealing with device address

Align locking usage when touching device address with rest
of the kernel. Lock the bottom half when doing so using
netif_addr_lock_bh.

This also solves the following case as reported by lockdep:
	CPU0                    CPU1
	----                    ----
lock(_xmit_INFINIBAND);
				local_irq_disable();
				lock(&(&mc->mca_lock)->rlock);
				lock(_xmit_INFINIBAND);
<Interrupt>
lock(&(&mc->mca_lock)->rlock);

*** DEADLOCK ***

Fixes: 492a7e67ff83 ("IB/IPoIB: Allow setting the device address")
Signed-off-by: Mark Bloch <markb@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
diff --git a/drivers/infiniband/ulp/ipoib/ipoib_ib.c b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
index 45c40a1..dc6d241 100644
--- a/drivers/infiniband/ulp/ipoib/ipoib_ib.c
+++ b/drivers/infiniband/ulp/ipoib/ipoib_ib.c
@@ -1015,7 +1015,7 @@
 	if (ib_query_gid(priv->ca, priv->port, 0, &gid0, NULL))
 		return false;
 
-	netif_addr_lock(priv->dev);
+	netif_addr_lock_bh(priv->dev);
 
 	/* The subnet prefix may have changed, update it now so we won't have
 	 * to do it later
@@ -1026,12 +1026,12 @@
 
 	search_gid.global.interface_id = priv->local_gid.global.interface_id;
 
-	netif_addr_unlock(priv->dev);
+	netif_addr_unlock_bh(priv->dev);
 
 	err = ib_find_gid(priv->ca, &search_gid, IB_GID_TYPE_IB,
 			  priv->dev, &port, &index);
 
-	netif_addr_lock(priv->dev);
+	netif_addr_lock_bh(priv->dev);
 
 	if (search_gid.global.interface_id !=
 	    priv->local_gid.global.interface_id)
@@ -1092,7 +1092,7 @@
 	}
 
 out:
-	netif_addr_unlock(priv->dev);
+	netif_addr_unlock_bh(priv->dev);
 
 	return ret;
 }