bonding: rebuild the lock use for bond_loadbalance_arp_mon()
Subsystems (3)
PATCH v2 4/10 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 <[email protected]>
Suggested-by Veaceslav Falico <[email protected]>
Signed-off-by Ding Tianhong <[email protected]>
--- drivers/net/bonding/bond_main.c | 20 ++++++++++++++------ 1 file changed, 14 insertions(+), 6 deletions(-)
drivers/net/bonding/bond_main.c +14 -6
@@ -2407,12 +2407,14 @@ void bond_loadbalance_arp_mon(struct work_struct *work)struct list_head *iter;int do_failover =0 ; -read_lock (&bond->lock); +rcu_read_lock (); -if (!bond_has_slaves (bond)) +if (!bond_has_slaves_rcu (bond)) { +rcu_read_unlock (); goto re_arm; + } - oldcurrent = bond->curr_active_slave; + 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
@@ -2421,7 +2423,7 @@ 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 ) {
@@ -2483,7 +2485,14 @@ 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);
@@ -2491,14 +2500,13 @@ 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); }/*
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1.8.2.1