From 2e52f4fe3655c7a2311070c6713f7feabc75486c Mon Sep 17 00:00:00 2001 From: dingtianhong Date: Fri, 13 Dec 2013 10:19:50 +0800 Subject: bonding: rebuild the lock use for bond_loadbalance_arp_mon() The bond_loadbalance_arp_mon() use the bond lock to protect the bond slave list, it is no effect, so I could use RTNL or RCU to replace it, considering the performance impact, the RCU is more better here, so the bond lock replace with the RCU. The bond_select_active_slave() need RTNL and curr_slave_lock together, but there is no RTNL lock here, so add a rtnl_rtylock. Suggested-by: Jay Vosburgh Suggested-by: Veaceslav Falico Signed-off-by: Ding Tianhong Signed-off-by: David S. Miller --- drivers/net/bonding/bond_main.c | 18 ++++++++++++------ 1 file changed, 12 insertions(+), 6 deletions(-) (limited to 'drivers') diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c index b34634a96710..1781ea620d76 100644 --- a/drivers/net/bonding/bond_main.c +++ b/drivers/net/bonding/bond_main.c @@ -2411,12 +2411,12 @@ void bond_loadbalance_arp_mon(struct work_struct *work) struct list_head *iter; int do_failover = 0; - read_lock(&bond->lock); - if (!bond_has_slaves(bond)) goto re_arm; - oldcurrent = bond->curr_active_slave; + rcu_read_lock(); + + oldcurrent = ACCESS_ONCE(bond->curr_active_slave); /* see if any of the previous devices are up now (i.e. they have * xmt and rcv traffic). the curr_active_slave does not come into * the picture unless it is null. also, slave->jiffies is not needed @@ -2425,7 +2425,7 @@ void bond_loadbalance_arp_mon(struct work_struct *work) * TODO: what about up/down delay in arp mode? it wasn't here before * so it can wait */ - bond_for_each_slave(bond, slave, iter) { + bond_for_each_slave_rcu(bond, slave, iter) { unsigned long trans_start = dev_trans_start(slave->dev); if (slave->link != BOND_LINK_UP) { @@ -2487,7 +2487,14 @@ void bond_loadbalance_arp_mon(struct work_struct *work) bond_arp_send_all(bond, slave); } + rcu_read_unlock(); + if (do_failover) { + /* the bond_select_active_slave must hold RTNL + * and curr_slave_lock for write. + */ + if (!rtnl_trylock()) + goto re_arm; block_netpoll_tx(); write_lock_bh(&bond->curr_slave_lock); @@ -2495,14 +2502,13 @@ 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); } /* -- cgit v1.2.3-59-g8ed1b