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 eb320c3..f2e2872 100644
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -959,19 +959,34 @@
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 @@
}
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 @@
* 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 @@
}
}
+ /*
+ * 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 @@
/* 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 @@
}
}
+ 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 @@
}
}
+ read_lock(&bond->lock);
+ write_lock_bh(&bond->curr_slave_lock);
+
return 0;
}