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bonding: simplify and fix peer notification 

This patch aims to remove a use of the bond->lock for mutual exclusion
which will later allow easier migration to RCU of the users of this
functionality. We use RTNL as a synchronizing mechanism since it's
always held when send_peer_notif is set, and when it is decremented from
the notifier function. We can also drop some locking, and fix the
leakage of the send_peer_notif counter.

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
nikolay@redhat.com 2013-09-02 13:51:38 +02:00 committed by David S. Miller
parent f7c6be404d
commit 6c8d23f786
1 changed files with 7 additions and 15 deletions
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22
drivers/net/bonding/bond_main.c
View File

@ -828,7 +828,6 @@ static bool bond_should_notify_peers(struct bonding *bond)
test_bit(__LINK_STATE_LINKWATCH_PENDING, &slave->dev->state))
return false;
bond->send_peer_notif--;
return true;
}
@ -2259,12 +2258,8 @@ re_arm:
read_unlock(&bond->lock);
if (should_notify_peers) {
if (!rtnl_trylock()) {
read_lock(&bond->lock);
bond->send_peer_notif++;
read_unlock(&bond->lock);
if (!rtnl_trylock())
return;
}
call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev);
rtnl_unlock();
}
@ -2876,12 +2871,8 @@ re_arm:
read_unlock(&bond->lock);
if (should_notify_peers) {
if (!rtnl_trylock()) {
read_lock(&bond->lock);
bond->send_peer_notif++;
read_unlock(&bond->lock);
if (!rtnl_trylock())
return;
}
call_netdevice_notifiers(NETDEV_NOTIFY_PEERS, bond->dev);
rtnl_unlock();
}
@ -2916,6 +2907,10 @@ static int bond_master_netdev_event(unsigned long event,
case NETDEV_REGISTER:
bond_create_proc_entry(event_bond);
break;
case NETDEV_NOTIFY_PEERS:
if (event_bond->send_peer_notif)
event_bond->send_peer_notif--;
break;
default:
break;
}
@ -3213,11 +3208,8 @@ static int bond_close(struct net_device *bond_dev)
{
struct bonding *bond = netdev_priv(bond_dev);
write_lock_bh(&bond->lock);
bond->send_peer_notif = 0;
write_unlock_bh(&bond->lock);
bond_work_cancel_all(bond);
bond->send_peer_notif = 0;
if (bond_is_lb(bond)) {
/* Must be called only after all
* slaves have been released