Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 2d0dafb0 authored by dingtianhong's avatar dingtianhong Committed by David S. Miller
Browse files

bonding: remove bond read lock for bond_alb_monitor() 



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 have 3 ways 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 existing 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 move the rtnl lock to protect the whole monitor function.

Signed-off-by: default avatarDing Tianhong <dingtianhong@huawei.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6b6c5261

drivers/net/bonding/bond_alb.c

+4 −16
Original line number Diff line number Diff line
@@ -1495,11 +1495,13 @@ void bond_alb_monitor(struct work_struct *work) 
	struct list_head *iter;

	struct slave *slave;



	read_lock(&bond->lock);

	if (!rtnl_trylock())

		goto re_arm;



	if (!bond_has_slaves(bond)) {

		bond_info->tx_rebalance_counter = 0;

		bond_info->lp_counter = 0;

		rtnl_unlock();

		goto re_arm;

	}
@@ -1548,16 +1550,6 @@ void bond_alb_monitor(struct work_struct *work) 
		if (bond_info->primary_is_promisc &&

		    (++bond_info->rlb_promisc_timeout_counter >= RLB_PROMISC_TIMEOUT)) {



			/*

			 * dev_set_promiscuity requires rtnl and

			 * nothing else.  Avoid race with bond_close.

			 */

			read_unlock(&bond->lock);

			if (!rtnl_trylock()) {

				read_lock(&bond->lock);

				goto re_arm;

			}



			bond_info->rlb_promisc_timeout_counter = 0;



			/* If the primary was set to promiscuous mode
@@ -1566,9 +1558,6 @@ void bond_alb_monitor(struct work_struct *work) 
			 */

			dev_set_promiscuity(bond->curr_active_slave->dev, -1);

			bond_info->primary_is_promisc = 0;



			rtnl_unlock();

			read_lock(&bond->lock);

		}



		if (bond_info->rlb_rebalance) {
@@ -1591,10 +1580,9 @@ void bond_alb_monitor(struct work_struct *work) 
		}

	}



	rtnl_unlock();

re_arm:

	queue_delayed_work(bond->wq, &bond->alb_work, alb_delta_in_ticks);



	read_unlock(&bond->lock);

}



/* assumption: called before the slave is attached to the bond