Subject: [PATCH net-next 2/5] bonding: remove bond read lock for bond_alb_monitor()

From: Ding Tianhong <[email-masked]>
Date: Mon, 21 Oct 2013 16:58:53 +0800

the bond now only attach and detach slave in rtnl lock,
so read_lock for bond could not protect slave list,
replace bond read lock with rtnl lock for bond_alb_monitor().

Signed-off-by: Ding Tianhong <[email-masked]>
---
 drivers/net/bonding/bond_alb.c | 20 ++++----------------
 1 file changed, 4 insertions(+), 16 deletions(-)

diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index 0287240..5d79f5e 100644
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -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
-- 
1.8.2.1