bonding: remove bond read lock for bond_loadbalance_arp_mon()
Subsystems (3)
PATCH v2 3/5 bonding: remove bond read lock for bond_loadbalance_arp_mon()
The bond slave list may change when the monitor is running, the slave list is no longer protected by bond->lock, only protected by rtnl lock(), so we has 3 way to modify it:
1.add bond_master_upper_dev_link() and bond_upper_dev_unlink() in bond->lock, but it is unsafe to call call_netdevice_notifiers() in write lock.
2.remove unused bond->lock for monitor function, only use the exist rtnl lock(). 3.use rcu_read_lock() to protect it, of course, it will transform bond_for_each_slave to bond_for_each_slave_rcu() and performance is better, but in slow path, it is ignored. so I remove the bond->lock and add the rtnl lock to protect the whole monitor function.
Signed-off-by Ding Tianhong <[email protected]>
--- drivers/net/bonding/bond_main.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
drivers/net/bonding/bond_main.c +6 -4
@@ -2433,10 +2433,13 @@ void bond_loadbalance_arp_mon(struct work_struct *work)struct list_head *iter;int do_failover =0 ; -read_lock (&bond->lock); +if (!rtnl_trylock ()) + goto re_arm; -if (!bond_has_slaves (bond)) +if (!bond_has_slaves (bond)) { +rtnl_unlock (); goto re_arm; + } oldcurrent = bond->curr_active_slave;/* see if any of the previous devices are up now (i.e. they have
@@ -2518,13 +2521,12 @@ void bond_loadbalance_arp_mon(struct work_struct *work)write_unlock_bh (&bond->curr_slave_lock);unblock_netpoll_tx (); } +rtnl_unlock (); re_arm:if (bond->params.arp_interval)queue_delayed_work (bond->wq, &bond->arp_work,msecs_to_jiffies (bond->params.arp_interval)); - -read_unlock (&bond->lock); }/*
Signature · 1 line
1.8.2.1