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>

diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index eb320c3cbddeb702f0649ad74b90e30d31817a09..f2e2872c9b175caa7b417bb4581f3f85ddd59a9c 100644 (file)
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -959,19 +959,34 @@ static int alb_set_slave_mac_addr(struct slave *slave, u8 addr[], int hw)
        return 0;
 }
 
-/* Caller must hold bond lock for write or curr_slave_lock for write*/
+/*
+ * Swap MAC addresses between two slaves.
+ *
+ * Called with RTNL held, and no other locks.
+ *
+ */
+
 static void alb_swap_mac_addr(struct bonding *bond, struct slave *slave1, struct slave *slave2)
 {
-       struct slave *disabled_slave = NULL;
        u8 tmp_mac_addr[ETH_ALEN];
-       int slaves_state_differ;
-
-       slaves_state_differ = (SLAVE_IS_OK(slave1) != SLAVE_IS_OK(slave2));
 
        memcpy(tmp_mac_addr, slave1->dev->dev_addr, ETH_ALEN);
        alb_set_slave_mac_addr(slave1, slave2->dev->dev_addr, bond->alb_info.rlb_enabled);
        alb_set_slave_mac_addr(slave2, tmp_mac_addr, bond->alb_info.rlb_enabled);
 
+}
+
+/*
+ * Send learning packets after MAC address swap.
+ *
+ * Called with RTNL and bond->lock held for read.
+ */
+static void alb_fasten_mac_swap(struct bonding *bond, struct slave *slave1,
+                               struct slave *slave2)
+{
+       int slaves_state_differ = (SLAVE_IS_OK(slave1) != SLAVE_IS_OK(slave2));
+       struct slave *disabled_slave = NULL;
+
        /* fasten the change in the switch */
        if (SLAVE_IS_OK(slave1)) {
                alb_send_learning_packets(slave1, slave1->dev->dev_addr);
@@ -1044,7 +1059,9 @@ static void alb_change_hw_addr_on_detach(struct bonding *bond, struct slave *sla
                }
 
                if (found) {
+                       /* locking: needs RTNL and nothing else */
                        alb_swap_mac_addr(bond, slave, tmp_slave);
+                       alb_fasten_mac_swap(bond, slave, tmp_slave);
                }
        }
 }
@@ -1571,13 +1588,21 @@ void bond_alb_handle_link_change(struct bonding *bond, struct slave *slave, char
  * Set the bond->curr_active_slave to @new_slave and handle
  * mac address swapping and promiscuity changes as needed.
  *
- * Caller must hold bond curr_slave_lock for write (or bond lock for write)
+ * If new_slave is NULL, caller must hold curr_slave_lock or
+ * bond->lock for write.
+ *
+ * If new_slave is not NULL, caller must hold RTNL, bond->lock for
+ * read and curr_slave_lock for write.  Processing here may sleep, so
+ * no other locks may be held.
  */
 void bond_alb_handle_active_change(struct bonding *bond, struct slave *new_slave)
 {
        struct slave *swap_slave;
        int i;
 
+       if (new_slave)
+               ASSERT_RTNL();
+
        if (bond->curr_active_slave == new_slave) {
                return;
        }
@@ -1610,6 +1635,19 @@ void bond_alb_handle_active_change(struct bonding *bond, struct slave *new_slave
                }
        }
 
+       /*
+        * Arrange for swap_slave and new_slave to temporarily be
+        * ignored so we can mess with their MAC addresses without
+        * fear of interference from transmit activity.
+        */
+       if (swap_slave) {
+               tlb_clear_slave(bond, swap_slave, 1);
+       }
+       tlb_clear_slave(bond, new_slave, 1);
+
+       write_unlock_bh(&bond->curr_slave_lock);
+       read_unlock(&bond->lock);
+
        /* curr_active_slave must be set before calling alb_swap_mac_addr */
        if (swap_slave) {
                /* swap mac address */
@@ -1618,11 +1656,23 @@ void bond_alb_handle_active_change(struct bonding *bond, struct slave *new_slave
                /* set the new_slave to the bond mac address */
                alb_set_slave_mac_addr(new_slave, bond->dev->dev_addr,
                                       bond->alb_info.rlb_enabled);
+       }
+
+       read_lock(&bond->lock);
+
+       if (swap_slave) {
+               alb_fasten_mac_swap(bond, swap_slave, new_slave);
+       } else {
                /* fasten bond mac on new current slave */
                alb_send_learning_packets(new_slave, bond->dev->dev_addr);
        }
+
+       write_lock_bh(&bond->curr_slave_lock);
 }
 
+/*
+ * Called with RTNL
+ */
 int bond_alb_set_mac_address(struct net_device *bond_dev, void *addr)
 {
        struct bonding *bond = bond_dev->priv;
@@ -1659,8 +1709,12 @@ int bond_alb_set_mac_address(struct net_device *bond_dev, void *addr)
                }
        }
 
+       write_unlock_bh(&bond->curr_slave_lock);
+       read_unlock(&bond->lock);
+
        if (swap_slave) {
                alb_swap_mac_addr(bond, swap_slave, bond->curr_active_slave);
+               alb_fasten_mac_swap(bond, swap_slave, bond->curr_active_slave);
        } else {
                alb_set_slave_mac_addr(bond->curr_active_slave, bond_dev->dev_addr,
                                       bond->alb_info.rlb_enabled);
@@ -1672,6 +1726,9 @@ int bond_alb_set_mac_address(struct net_device *bond_dev, void *addr)
                }
        }
 
+       read_lock(&bond->lock);
+       write_lock_bh(&bond->curr_slave_lock);
+
        return 0;
 }
 

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index a3577271b1b8350b35d45ecf5b08497743669c20..15c1f7ad222b45b1927d9406f8af44e4d28be860 100644 (file)
--- 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;