bonding: Convert locks to _bh, rework alb locking for new locking

	Convert locking-related activity to new & improved system.
Convert some lock acquisitions to _bh and rework parts of ALB mode, both
to avoid deadlocks with workqueue activity.

Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 54 insertions, 24 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index a3577271b1b8..15c1f7ad222b 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1590,15 +1590,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
         case BOND_MODE_TLB:
         case BOND_MODE_ALB:
                 new_slave->state = BOND_STATE_ACTIVE;
-                if ((!bond->curr_active_slave) &&
-                    (new_slave->link != BOND_LINK_DOWN)) {
-                        /* first slave or no active slave yet, and this link
-                         * is OK, so make this interface the active one
-                         */
-                        bond_change_active_slave(bond, new_slave);
-                } else {
-                        bond_set_slave_inactive_flags(new_slave);
-                }
+                bond_set_slave_inactive_flags(new_slave);
                 break;
         default:
                 dprintk("This slave is always active in trunk mode\n");
@@ -1754,9 +1746,23 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
                 bond_alb_deinit_slave(bond, slave);
         }
 
-        if (oldcurrent == slave)
+        if (oldcurrent == slave) {
+                /*
+                 * Note that we hold RTNL over this sequence, so there
+                 * is no concern that another slave add/remove event
+                 * will interfere.
+                 */
+                write_unlock_bh(&bond->lock);
+                read_lock(&bond->lock);
+                write_lock_bh(&bond->curr_slave_lock);
+
                 bond_select_active_slave(bond);
 
+                write_unlock_bh(&bond->curr_slave_lock);
+                read_unlock(&bond->lock);
+                write_lock_bh(&bond->lock);
+        }
+
         if (bond->slave_cnt == 0) {
                 bond_set_carrier(bond);
 
@@ -2012,16 +2018,19 @@ static int bond_ioctl_change_active(struct net_device *bond_dev, struct net_devi
                 return -EINVAL;
         }
 
-        write_lock_bh(&bond->lock);
+        read_lock(&bond->lock);
 
+        read_lock(&bond->curr_slave_lock);
         old_active = bond->curr_active_slave;
+        read_unlock(&bond->curr_slave_lock);
+
         new_active = bond_get_slave_by_dev(bond, slave_dev);
 
         /*
          * Changing to the current active: do nothing; return success.
          */
         if (new_active && (new_active == old_active)) {
-                write_unlock_bh(&bond->lock);
+                read_unlock(&bond->lock);
                 return 0;
         }
 
@@ -2029,12 +2038,14 @@ static int bond_ioctl_change_active(struct net_device *bond_dev, struct net_devi
             (old_active) &&
             (new_active->link == BOND_LINK_UP) &&
             IS_UP(new_active->dev)) {
+                write_lock_bh(&bond->curr_slave_lock);
                 bond_change_active_slave(bond, new_active);
+                write_unlock_bh(&bond->curr_slave_lock);
         } else {
                 res = -EINVAL;
         }
 
-        write_unlock_bh(&bond->lock);
+        read_unlock(&bond->lock);
 
         return res;
 }
@@ -2140,7 +2151,11 @@ static int __bond_mii_monitor(struct bonding *bond, int have_locks)
                 switch (slave->link) {
                 case BOND_LINK_UP:      /* the link was up */
                         if (link_state == BMSR_LSTATUS) {
-                                /* link stays up, nothing more to do */
+                                if (!oldcurrent) {
+                                        if (!have_locks)
+                                                return 1;
+                                        do_failover = 1;
+                                }
                                 break;
                         } else { /* link going down */
                                 slave->link  = BOND_LINK_FAIL;
@@ -2327,11 +2342,14 @@ static int __bond_mii_monitor(struct bonding *bond, int have_locks)
         } /* end of for */
 
         if (do_failover) {
-                write_lock(&bond->curr_slave_lock);
+                ASSERT_RTNL();
+
+                write_lock_bh(&bond->curr_slave_lock);
 
                 bond_select_active_slave(bond);
 
-                write_unlock(&bond->curr_slave_lock);
+                write_unlock_bh(&bond->curr_slave_lock);
+
         } else
                 bond_set_carrier(bond);
 
@@ -2770,11 +2788,14 @@ void bond_loadbalance_arp_mon(struct work_struct *work)
         }
 
         if (do_failover) {
-                write_lock(&bond->curr_slave_lock);
+                rtnl_lock();
+                write_lock_bh(&bond->curr_slave_lock);
 
                 bond_select_active_slave(bond);
 
-                write_unlock(&bond->curr_slave_lock);
+                write_unlock_bh(&bond->curr_slave_lock);
+                rtnl_unlock();
+
         }
 
 re_arm:
@@ -2831,7 +2852,9 @@ void bond_activebackup_arp_mon(struct work_struct *work)
 
                                 slave->link = BOND_LINK_UP;
 
-                                write_lock(&bond->curr_slave_lock);
+                                rtnl_lock();
+
+                                write_lock_bh(&bond->curr_slave_lock);
 
                                 if ((!bond->curr_active_slave) &&
                                     ((jiffies - slave->dev->trans_start) <= delta_in_ticks)) {
@@ -2865,7 +2888,8 @@ void bond_activebackup_arp_mon(struct work_struct *work)
                                                slave->dev->name);
                                 }
 
-                                write_unlock(&bond->curr_slave_lock);
+                                write_unlock_bh(&bond->curr_slave_lock);
+                                rtnl_unlock();
                         }
                 } else {
                         read_lock(&bond->curr_slave_lock);
@@ -2935,12 +2959,15 @@ void bond_activebackup_arp_mon(struct work_struct *work)
                                bond->dev->name,
                                slave->dev->name);
 
-                        write_lock(&bond->curr_slave_lock);
+                        rtnl_lock();
+                        write_lock_bh(&bond->curr_slave_lock);
 
                         bond_select_active_slave(bond);
                         slave = bond->curr_active_slave;
 
-                        write_unlock(&bond->curr_slave_lock);
+                        write_unlock_bh(&bond->curr_slave_lock);
+
+                        rtnl_unlock();
 
                         bond->current_arp_slave = slave;
 
@@ -2959,9 +2986,12 @@ void bond_activebackup_arp_mon(struct work_struct *work)
                                bond->primary_slave->dev->name);
 
                         /* primary is up so switch to it */
-                        write_lock(&bond->curr_slave_lock);
+                        rtnl_lock();
+                        write_lock_bh(&bond->curr_slave_lock);
                         bond_change_active_slave(bond, bond->primary_slave);
-                        write_unlock(&bond->curr_slave_lock);
+                        write_unlock_bh(&bond->curr_slave_lock);
+
+                        rtnl_unlock();
 
                         slave = bond->primary_slave;
                         slave->jiffies = jiffies;