bonding: register slave pointer for rx_handler

Register slave pointer as rx_handler data. That would eventually prevent
need to loop over slave devices to find the right slave.

Use synchronize_net to ensure that bond_handle_frame does not get slave
structure freed when working with that.

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Reviewed-by: Nicolas de Pesloüan <nicolas.2p.debian@free.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 14 insertions, 6 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 66c98e61f0b7..b047d75c28d4 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1482,21 +1482,22 @@ static bool bond_should_deliver_exact_match(struct sk_buff *skb,
 
 static struct sk_buff *bond_handle_frame(struct sk_buff *skb)
 {
-        struct net_device *slave_dev;
+        struct slave *slave;
         struct net_device *bond_dev;
 
         skb = skb_share_check(skb, GFP_ATOMIC);
         if (unlikely(!skb))
                 return NULL;
-        slave_dev = skb->dev;
-        bond_dev = ACCESS_ONCE(slave_dev->master);
+
+        slave = bond_slave_get_rcu(skb->dev);
+        bond_dev = ACCESS_ONCE(slave->dev->master);
         if (unlikely(!bond_dev))
                 return skb;
 
         if (bond_dev->priv_flags & IFF_MASTER_ARPMON)
-                slave_dev->last_rx = jiffies;
+                slave->dev->last_rx = jiffies;
 
-        if (bond_should_deliver_exact_match(skb, slave_dev, bond_dev)) {
+        if (bond_should_deliver_exact_match(skb, slave->dev, bond_dev)) {
                 skb->deliver_no_wcard = 1;
                 return skb;
         }
@@ -1694,7 +1695,8 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
                 pr_debug("Error %d calling netdev_set_bond_master\n", res);
                 goto err_restore_mac;
         }
-        res = netdev_rx_handler_register(slave_dev, bond_handle_frame, NULL);
+        res = netdev_rx_handler_register(slave_dev, bond_handle_frame,
+                                         new_slave);
         if (res) {
                 pr_debug("Error %d calling netdev_rx_handler_register\n", res);
                 goto err_unset_master;
@@ -1916,6 +1918,7 @@ err_close:
 
 err_unreg_rxhandler:
         netdev_rx_handler_unregister(slave_dev);
+        synchronize_net();
 
 err_unset_master:
         netdev_set_bond_master(slave_dev, NULL);
@@ -2099,6 +2102,7 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
         }
 
         netdev_rx_handler_unregister(slave_dev);
+        synchronize_net();
         netdev_set_bond_master(slave_dev, NULL);
 
         slave_disable_netpoll(slave);
@@ -2213,6 +2217,7 @@ static int bond_release_all(struct net_device *bond_dev)
                 }
 
                 netdev_rx_handler_unregister(slave_dev);
+                synchronize_net();
                 netdev_set_bond_master(slave_dev, NULL);
 
                 slave_disable_netpoll(slave);
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index c4e2343bb0b7..ff9af31e8c5b 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -266,6 +266,9 @@ struct bonding {
 #endif /* CONFIG_DEBUG_FS */
 };
 
+#define bond_slave_get_rcu(dev) \
+        ((struct slave *) rcu_dereference(dev->rx_handler_data))
+
 /**
  * Returns NULL if the net_device does not belong to any of the bond's slaves
  *