2 files changed, 248 insertions, 185 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index fa3c2101fe75..51e0f2de42c6 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1051,6 +1051,8 @@ void bond_change_active_slave(struct bonding *bond, struct slave *new_active)
         }
 
         if (new_active) {
+                new_active->jiffies = jiffies;
+
                 if (new_active->link == BOND_LINK_BACK) {
                         if (USES_PRIMARY(bond->params.mode)) {
                                 printk(KERN_INFO DRV_NAME
@@ -1062,7 +1064,6 @@ void bond_change_active_slave(struct bonding *bond, struct slave *new_active)
 
                         new_active->delay = 0;
                         new_active->link = BOND_LINK_UP;
-                        new_active->jiffies = jiffies;
 
                         if (bond->params.mode == BOND_MODE_8023AD) {
                                 bond_3ad_handle_link_change(new_active, BOND_LINK_UP);
@@ -2795,243 +2796,299 @@ out:
 }
 
 /*
- * When using arp monitoring in active-backup mode, this function is
- * called to determine if any backup slaves have went down or a new
- * current slave needs to be found.
- * The backup slaves never generate traffic, they are considered up by merely
- * receiving traffic. If the current slave goes down, each backup slave will
- * be given the opportunity to tx/rx an arp before being taken down - this
- * prevents all slaves from being taken down due to the current slave not
- * sending any traffic for the backups to receive. The arps are not necessarily
- * necessary, any tx and rx traffic will keep the current slave up. While any
- * rx traffic will keep the backup slaves up, the current slave is responsible
- * for generating traffic to keep them up regardless of any other traffic they
- * may have received.
- * see loadbalance_arp_monitor for arp monitoring in load balancing mode
+ * Called to inspect slaves for active-backup mode ARP monitor link state
+ * changes.  Sets new_link in slaves to specify what action should take
+ * place for the slave.  Returns 0 if no changes are found, >0 if changes
+ * to link states must be committed.
+ *
+ * Called with bond->lock held for read.
  */
-void bond_activebackup_arp_mon(struct work_struct *work)
+static int bond_ab_arp_inspect(struct bonding *bond, int delta_in_ticks)
 {
-        struct bonding *bond = container_of(work, struct bonding,
-                                            arp_work.work);
         struct slave *slave;
-        int delta_in_ticks;
-        int i;
+        int i, commit = 0;
 
-        read_lock(&bond->lock);
+        bond_for_each_slave(bond, slave, i) {
+                slave->new_link = BOND_LINK_NOCHANGE;
 
-        delta_in_ticks = msecs_to_jiffies(bond->params.arp_interval);
+                if (slave->link != BOND_LINK_UP) {
+                        if (time_before_eq(jiffies, slave_last_rx(bond, slave) +
+                                           delta_in_ticks)) {
+                                slave->new_link = BOND_LINK_UP;
+                                commit++;
+                        }
 
-        if (bond->kill_timers) {
-                goto out;
-        }
+                        continue;
+                }
 
-        if (bond->slave_cnt == 0) {
-                goto re_arm;
+                /*
+                 * Give slaves 2*delta after being enslaved or made
+                 * active.  This avoids bouncing, as the last receive
+                 * times need a full ARP monitor cycle to be updated.
+                 */
+                if (!time_after_eq(jiffies, slave->jiffies +
+                                   2 * delta_in_ticks))
+                        continue;
+
+                /*
+                 * Backup slave is down if:
+                 * - No current_arp_slave AND
+                 * - more than 3*delta since last receive AND
+                 * - the bond has an IP address
+                 *
+                 * Note: a non-null current_arp_slave indicates
+                 * the curr_active_slave went down and we are
+                 * searching for a new one; under this condition
+                 * we only take the curr_active_slave down - this
+                 * gives each slave a chance to tx/rx traffic
+                 * before being taken out
+                 */
+                if (slave->state == BOND_STATE_BACKUP &&
+                    !bond->current_arp_slave &&
+                    time_after(jiffies, slave_last_rx(bond, slave) +
+                               3 * delta_in_ticks)) {
+                        slave->new_link = BOND_LINK_DOWN;
+                        commit++;
+                }
+
+                /*
+                 * Active slave is down if:
+                 * - more than 2*delta since transmitting OR
+                 * - (more than 2*delta since receive AND
+                 *    the bond has an IP address)
+                 */
+                if ((slave->state == BOND_STATE_ACTIVE) &&
+                    (time_after_eq(jiffies, slave->dev->trans_start +
+                                    2 * delta_in_ticks) ||
+                      (time_after_eq(jiffies, slave_last_rx(bond, slave)
+                                     + 2 * delta_in_ticks)))) {
+                        slave->new_link = BOND_LINK_DOWN;
+                        commit++;
+                }
         }
 
-        /* determine if any slave has come up or any backup slave has
-         * gone down
-         * TODO: what about up/down delay in arp mode? it wasn't here before
-         *       so it can wait
+        read_lock(&bond->curr_slave_lock);
+
+        /*
+         * Trigger a commit if the primary option setting has changed.
          */
-        bond_for_each_slave(bond, slave, i) {
-                if (slave->link != BOND_LINK_UP) {
-                        if (time_before_eq(jiffies,
-                            slave_last_rx(bond, slave) + delta_in_ticks)) {
+        if (bond->primary_slave &&
+            (bond->primary_slave != bond->curr_active_slave) &&
+            (bond->primary_slave->link == BOND_LINK_UP))
+                commit++;
 
-                                slave->link = BOND_LINK_UP;
+        read_unlock(&bond->curr_slave_lock);
 
-                                write_lock_bh(&bond->curr_slave_lock);
+        return commit;
+}
 
-                                if ((!bond->curr_active_slave) &&
-                                    time_before_eq(jiffies, slave->dev->trans_start + delta_in_ticks)) {
-                                        bond_change_active_slave(bond, slave);
-                                        bond->current_arp_slave = NULL;
-                                } else if (bond->curr_active_slave != slave) {
-                                        /* this slave has just come up but we
-                                         * already have a current slave; this
-                                         * can also happen if bond_enslave adds
-                                         * a new slave that is up while we are
-                                         * searching for a new slave
-                                         */
-                                        bond_set_slave_inactive_flags(slave);
-                                        bond->current_arp_slave = NULL;
-                                }
+/*
+ * Called to commit link state changes noted by inspection step of
+ * active-backup mode ARP monitor.
+ *
+ * Called with RTNL and bond->lock for read.
+ */
+static void bond_ab_arp_commit(struct bonding *bond, int delta_in_ticks)
+{
+        struct slave *slave;
+        int i;
 
-                                bond_set_carrier(bond);
+        bond_for_each_slave(bond, slave, i) {
+                switch (slave->new_link) {
+                case BOND_LINK_NOCHANGE:
+                        continue;
 
-                                if (slave == bond->curr_active_slave) {
-                                        printk(KERN_INFO DRV_NAME
-                                               ": %s: %s is up and now the "
-                                               "active interface\n",
-                                               bond->dev->name,
-                                               slave->dev->name);
-                                        netif_carrier_on(bond->dev);
-                                } else {
-                                        printk(KERN_INFO DRV_NAME
-                                               ": %s: backup interface %s is "
-                                               "now up\n",
-                                               bond->dev->name,
-                                               slave->dev->name);
-                                }
+                case BOND_LINK_UP:
+                        write_lock_bh(&bond->curr_slave_lock);
 
-                                write_unlock_bh(&bond->curr_slave_lock);
-                        }
-                } else {
-                        read_lock(&bond->curr_slave_lock);
+                        if (!bond->curr_active_slave &&
+                            time_before_eq(jiffies, slave->dev->trans_start +
+                                           delta_in_ticks)) {
+                                slave->link = BOND_LINK_UP;
+                                bond_change_active_slave(bond, slave);
+                                bond->current_arp_slave = NULL;
 
-                        if ((slave != bond->curr_active_slave) &&
-                            (!bond->current_arp_slave) &&
-                            (time_after_eq(jiffies, slave_last_rx(bond, slave) + 3*delta_in_ticks))) {
-                                /* a backup slave has gone down; three times
-                                 * the delta allows the current slave to be
-                                 * taken out before the backup slave.
-                                 * note: a non-null current_arp_slave indicates
-                                 * the curr_active_slave went down and we are
-                                 * searching for a new one; under this
-                                 * condition we only take the curr_active_slave
-                                 * down - this gives each slave a chance to
-                                 * tx/rx traffic before being taken out
+                                printk(KERN_INFO DRV_NAME
+                                       ": %s: %s is up and now the "
+                                       "active interface\n",
+                                       bond->dev->name, slave->dev->name);
+
+                        } else if (bond->curr_active_slave != slave) {
+                                /* this slave has just come up but we
+                                 * already have a current slave; this can
+                                 * also happen if bond_enslave adds a new
+                                 * slave that is up while we are searching
+                                 * for a new slave
                                  */
+                                slave->link = BOND_LINK_UP;
+                                bond_set_slave_inactive_flags(slave);
+                                bond->current_arp_slave = NULL;
+
+                                printk(KERN_INFO DRV_NAME
+                                       ": %s: backup interface %s is now up\n",
+                                       bond->dev->name, slave->dev->name);
+                        }
 
-                                read_unlock(&bond->curr_slave_lock);
+                        write_unlock_bh(&bond->curr_slave_lock);
 
-                                slave->link  = BOND_LINK_DOWN;
+                        break;
 
-                                if (slave->link_failure_count < UINT_MAX) {
-                                        slave->link_failure_count++;
-                                }
+                case BOND_LINK_DOWN:
+                        if (slave->link_failure_count < UINT_MAX)
+                                slave->link_failure_count++;
+
+                        slave->link = BOND_LINK_DOWN;
+
+                        if (slave == bond->curr_active_slave) {
+                                printk(KERN_INFO DRV_NAME
+                                       ": %s: link status down for active "
+                                       "interface %s, disabling it\n",
+                                       bond->dev->name, slave->dev->name);
 
                                 bond_set_slave_inactive_flags(slave);
 
+                                write_lock_bh(&bond->curr_slave_lock);
+
+                                bond_select_active_slave(bond);
+                                if (bond->curr_active_slave)
+                                        bond->curr_active_slave->jiffies =
+                                                jiffies;
+
+                                write_unlock_bh(&bond->curr_slave_lock);
+
+                                bond->current_arp_slave = NULL;
+
+                        } else if (slave->state == BOND_STATE_BACKUP) {
                                 printk(KERN_INFO DRV_NAME
                                        ": %s: backup interface %s is now down\n",
-                                       bond->dev->name,
-                                       slave->dev->name);
-                        } else {
-                                read_unlock(&bond->curr_slave_lock);
+                                       bond->dev->name, slave->dev->name);
+
+                                bond_set_slave_inactive_flags(slave);
                         }
+                        break;
+
+                default:
+                        printk(KERN_ERR DRV_NAME
+                               ": %s: impossible: new_link %d on slave %s\n",
+                               bond->dev->name, slave->new_link,
+                               slave->dev->name);
                 }
         }
 
-        read_lock(&bond->curr_slave_lock);
-        slave = bond->curr_active_slave;
-        read_unlock(&bond->curr_slave_lock);
-
-        if (slave) {
-                /* if we have sent traffic in the past 2*arp_intervals but
-                 * haven't xmit and rx traffic in that time interval, select
-                 * a different slave. slave->jiffies is only updated when
-                 * a slave first becomes the curr_active_slave - not necessarily
-                 * after every arp; this ensures the slave has a full 2*delta
-                 * before being taken out. if a primary is being used, check
-                 * if it is up and needs to take over as the curr_active_slave
-                 */
-                if ((time_after_eq(jiffies, slave->dev->trans_start + 2*delta_in_ticks) ||
-                     (time_after_eq(jiffies, slave_last_rx(bond, slave) + 2*delta_in_ticks))) &&
-                        time_after_eq(jiffies, slave->jiffies + 2*delta_in_ticks)) {
+        /*
+         * No race with changes to primary via sysfs, as we hold rtnl.
+         */
+        if (bond->primary_slave &&
+            (bond->primary_slave != bond->curr_active_slave) &&
+            (bond->primary_slave->link == BOND_LINK_UP)) {
+                write_lock_bh(&bond->curr_slave_lock);
+                bond_change_active_slave(bond, bond->primary_slave);
+                write_unlock_bh(&bond->curr_slave_lock);
+        }
 
-                        slave->link  = BOND_LINK_DOWN;
+        bond_set_carrier(bond);
+}
 
-                        if (slave->link_failure_count < UINT_MAX) {
-                                slave->link_failure_count++;
-                        }
+/*
+ * Send ARP probes for active-backup mode ARP monitor.
+ *
+ * Called with bond->lock held for read.
+ */
+static void bond_ab_arp_probe(struct bonding *bond)
+{
+        struct slave *slave;
+        int i;
 
-                        printk(KERN_INFO DRV_NAME
-                               ": %s: link status down for active interface "
-                               "%s, disabling it\n",
-                               bond->dev->name,
-                               slave->dev->name);
+        read_lock(&bond->curr_slave_lock);
 
-                        write_lock_bh(&bond->curr_slave_lock);
+        if (bond->current_arp_slave && bond->curr_active_slave)
+                printk("PROBE: c_arp %s && cas %s BAD\n",
+                       bond->current_arp_slave->dev->name,
+                       bond->curr_active_slave->dev->name);
 
-                        bond_select_active_slave(bond);
-                        slave = bond->curr_active_slave;
+        if (bond->curr_active_slave) {
+                bond_arp_send_all(bond, bond->curr_active_slave);
+                read_unlock(&bond->curr_slave_lock);
+                return;
+        }
 
-                        write_unlock_bh(&bond->curr_slave_lock);
+        read_unlock(&bond->curr_slave_lock);
 
-                        bond->current_arp_slave = slave;
+        /* if we don't have a curr_active_slave, search for the next available
+         * backup slave from the current_arp_slave and make it the candidate
+         * for becoming the curr_active_slave
+         */
 
-                        if (slave) {
-                                slave->jiffies = jiffies;
-                        }
-                } else if ((bond->primary_slave) &&
-                           (bond->primary_slave != slave) &&
-                           (bond->primary_slave->link == BOND_LINK_UP)) {
-                        /* at this point, slave is the curr_active_slave */
-                        printk(KERN_INFO DRV_NAME
-                               ": %s: changing from interface %s to primary "
-                               "interface %s\n",
-                               bond->dev->name,
-                               slave->dev->name,
-                               bond->primary_slave->dev->name);
+        if (!bond->current_arp_slave) {
+                bond->current_arp_slave = bond->first_slave;
+                if (!bond->current_arp_slave)
+                        return;
+        }
 
-                        /* primary is up so switch to it */
-                        write_lock_bh(&bond->curr_slave_lock);
-                        bond_change_active_slave(bond, bond->primary_slave);
-                        write_unlock_bh(&bond->curr_slave_lock);
+        bond_set_slave_inactive_flags(bond->current_arp_slave);
 
-                        slave = bond->primary_slave;
+        /* search for next candidate */
+        bond_for_each_slave_from(bond, slave, i, bond->current_arp_slave->next) {
+                if (IS_UP(slave->dev)) {
+                        slave->link = BOND_LINK_BACK;
+                        bond_set_slave_active_flags(slave);
+                        bond_arp_send_all(bond, slave);
                         slave->jiffies = jiffies;
-                } else {
-                        bond->current_arp_slave = NULL;
+                        bond->current_arp_slave = slave;
+                        break;
                 }
 
-                /* the current slave must tx an arp to ensure backup slaves
-                 * rx traffic
+                /* if the link state is up at this point, we
+                 * mark it down - this can happen if we have
+                 * simultaneous link failures and
+                 * reselect_active_interface doesn't make this
+                 * one the current slave so it is still marked
+                 * up when it is actually down
                  */
-                if (slave && IS_UP(slave->dev))
-                        bond_arp_send_all(bond, slave);
-        }
+                if (slave->link == BOND_LINK_UP) {
+                        slave->link = BOND_LINK_DOWN;
+                        if (slave->link_failure_count < UINT_MAX)
+                                slave->link_failure_count++;
 
-        /* if we don't have a curr_active_slave, search for the next available
-         * backup slave from the current_arp_slave and make it the candidate
-         * for becoming the curr_active_slave
-         */
-        if (!slave) {
-                if (!bond->current_arp_slave) {
-                        bond->current_arp_slave = bond->first_slave;
+                        bond_set_slave_inactive_flags(slave);
+
+                        printk(KERN_INFO DRV_NAME
+                               ": %s: backup interface %s is now down.\n",
+                               bond->dev->name, slave->dev->name);
                 }
+        }
+}
 
-                if (bond->current_arp_slave) {
-                        bond_set_slave_inactive_flags(bond->current_arp_slave);
+void bond_activebackup_arp_mon(struct work_struct *work)
+{
+        struct bonding *bond = container_of(work, struct bonding,
+                                            arp_work.work);
+        int delta_in_ticks;
 
-                        /* search for next candidate */
-                        bond_for_each_slave_from(bond, slave, i, bond->current_arp_slave->next) {
-                                if (IS_UP(slave->dev)) {
-                                        slave->link = BOND_LINK_BACK;
-                                        bond_set_slave_active_flags(slave);
-                                        bond_arp_send_all(bond, slave);
-                                        slave->jiffies = jiffies;
-                                        bond->current_arp_slave = slave;
-                                        break;
-                                }
+        read_lock(&bond->lock);
 
-                                /* if the link state is up at this point, we
-                                 * mark it down - this can happen if we have
-                                 * simultaneous link failures and
-                                 * reselect_active_interface doesn't make this
-                                 * one the current slave so it is still marked
-                                 * up when it is actually down
-                                 */
-                                if (slave->link == BOND_LINK_UP) {
-                                        slave->link  = BOND_LINK_DOWN;
-                                        if (slave->link_failure_count < UINT_MAX) {
-                                                slave->link_failure_count++;
-                                        }
+        if (bond->kill_timers)
+                goto out;
 
-                                        bond_set_slave_inactive_flags(slave);
+        delta_in_ticks = msecs_to_jiffies(bond->params.arp_interval);
 
-                                        printk(KERN_INFO DRV_NAME
-                                               ": %s: backup interface %s is "
-                                               "now down.\n",
-                                               bond->dev->name,
-                                               slave->dev->name);
-                                }
-                        }
-                }
+        if (bond->slave_cnt == 0)
+                goto re_arm;
+
+        if (bond_ab_arp_inspect(bond, delta_in_ticks)) {
+                read_unlock(&bond->lock);
+                rtnl_lock();
+                read_lock(&bond->lock);
+
+                bond_ab_arp_commit(bond, delta_in_ticks);
+
+                read_unlock(&bond->lock);
+                rtnl_unlock();
+                read_lock(&bond->lock);
         }
 
+        bond_ab_arp_probe(bond);
+
 re_arm:
         if (bond->params.arp_interval) {
                 queue_delayed_work(bond->wq, &bond->arp_work, delta_in_ticks);
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 46a2ed507b33..8766b1213690 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -158,6 +158,7 @@ struct slave {
         unsigned long jiffies;
         unsigned long last_arp_rx;
         s8     link;    /* one of BOND_LINK_XXXX */
+        s8     new_link;
         s8     state;   /* one of BOND_STATE_XXXX */
         u32    original_flags;
         u32    original_mtu;
@@ -170,6 +171,11 @@ struct slave {
 };
 
 /*
+ * Link pseudo-state only used internally by monitors
+ */
+#define BOND_LINK_NOCHANGE -1
+
+/*
  * Here are the locking policies for the two bonding locks:
  *
  * 1) Get bond->lock when reading/writing slave list.