bonding: don't lock when copying/clearing VLAN list on slave
When copying VLAN information to or removing from a slave
during slave addition or removal, the bonding code currently holds
the bond->lock for write to prevent concurrent modification of the
vlan_list / vlgrp.
This is unnecessary, as all of these operations occur under
RTNL. Holding the bond->lock also caused might_sleep issues for
some drivers' ndo_vlan_* functions. This patch removes the extra
locking.
Problem reported by Michael Chan <mchan@broadcom.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Cc: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index f3b01ce..2cc4cfc 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -570,10 +570,8 @@
struct vlan_entry *vlan;
const struct net_device_ops *slave_ops = slave_dev->netdev_ops;
- write_lock_bh(&bond->lock);
-
if (!bond->vlgrp)
- goto out;
+ return;
if ((slave_dev->features & NETIF_F_HW_VLAN_RX) &&
slave_ops->ndo_vlan_rx_register)
@@ -581,13 +579,10 @@
if (!(slave_dev->features & NETIF_F_HW_VLAN_FILTER) ||
!(slave_ops->ndo_vlan_rx_add_vid))
- goto out;
+ return;
list_for_each_entry(vlan, &bond->vlan_list, vlan_list)
slave_ops->ndo_vlan_rx_add_vid(slave_dev, vlan->vlan_id);
-
-out:
- write_unlock_bh(&bond->lock);
}
static void bond_del_vlans_from_slave(struct bonding *bond,
@@ -597,10 +592,8 @@
struct vlan_entry *vlan;
struct net_device *vlan_dev;
- write_lock_bh(&bond->lock);
-
if (!bond->vlgrp)
- goto out;
+ return;
if (!(slave_dev->features & NETIF_F_HW_VLAN_FILTER) ||
!(slave_ops->ndo_vlan_rx_kill_vid))
@@ -621,9 +614,6 @@
if ((slave_dev->features & NETIF_F_HW_VLAN_RX) &&
slave_ops->ndo_vlan_rx_register)
slave_ops->ndo_vlan_rx_register(slave_dev, NULL);
-
-out:
- write_unlock_bh(&bond->lock);
}
/*------------------------------- Link status -------------------------------*/