bonding: fix set_multicast_list locking

	This patch eliminates a problem (reported by lockdep) in the
bond_set_multicast_list function.  It first reduces the locking on
bond->lock to a simple read_lock, and second, adds netif_tx locking
around the bonding mc_list manipulations that occur outside of the
set_multicast_list function.

	The original problem was related to IPv6 addrconf activity.

Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 3 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 2766855a5aee..65c7ebafaacd 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1464,10 +1464,12 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
                         dev_set_allmulti(slave_dev, 1);
                 }
 
+                netif_tx_lock_bh(bond_dev);
                 /* upload master's mc_list to new slave */
                 for (dmi = bond_dev->mc_list; dmi; dmi = dmi->next) {
                         dev_mc_add (slave_dev, dmi->dmi_addr, dmi->dmi_addrlen, 0);
                 }
+                netif_tx_unlock_bh(bond_dev);
         }
 
         if (bond->params.mode == BOND_MODE_8023AD) {
@@ -1821,7 +1823,9 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
                 }
 
                 /* flush master's mc_list from slave */
+                netif_tx_lock_bh(bond_dev);
                 bond_mc_list_flush(bond_dev, slave_dev);
+                netif_tx_unlock_bh(bond_dev);
         }
 
         netdev_set_master(slave_dev, NULL);
@@ -1942,7 +1946,9 @@ static int bond_release_all(struct net_device *bond_dev)
                         }
 
                         /* flush master's mc_list from slave */
+                        netif_tx_lock_bh(bond_dev);
                         bond_mc_list_flush(bond_dev, slave_dev);
+                        netif_tx_unlock_bh(bond_dev);
                 }
 
                 netdev_set_master(slave_dev, NULL);
@@ -3937,8 +3943,6 @@ static void bond_set_multicast_list(struct net_device *bond_dev)
         struct bonding *bond = bond_dev->priv;
         struct dev_mc_list *dmi;
 
-        write_lock_bh(&bond->lock);
-
         /*
          * Do promisc before checking multicast_mode
          */
@@ -3959,6 +3963,8 @@ static void bond_set_multicast_list(struct net_device *bond_dev)
                 bond_set_allmulti(bond, -1);
         }
 
+        read_lock(&bond->lock);
+
         bond->flags = bond_dev->flags;
 
         /* looking for addresses to add to slaves' mc list */
@@ -3979,7 +3985,7 @@ static void bond_set_multicast_list(struct net_device *bond_dev)
         bond_mc_list_destroy(bond);
         bond_mc_list_copy(bond_dev->mc_list, bond, GFP_ATOMIC);
 
-        write_unlock_bh(&bond->lock);
+        read_unlock(&bond->lock);
 }
 
 /*
@@ -4526,7 +4532,9 @@ static void bond_free_all(void)
                 struct net_device *bond_dev = bond->dev;
 
                 bond_work_cancel_all(bond);
+                netif_tx_lock_bh(bond_dev);
                 bond_mc_list_destroy(bond);
+                netif_tx_unlock_bh(bond_dev);
                 /* Release the bonded slaves */
                 bond_release_all(bond_dev);
                 bond_deinit(bond_dev);