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bonding: Convert locks to _bh, rework alb locking for new locking
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	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>
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Jay Vosburgh authored and Jeff Garzik committed Oct 24, 2007
1 parent 0b0eef6 commit 059fe7a
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Showing 2 changed files with 117 additions and 30 deletions.
69 changes: 63 additions & 6 deletions drivers/net/bonding/bond_alb.c
View file
Expand Up @@ -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);
Expand Down Expand Up @@ -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);
}
}
}
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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 */
Expand All @@ -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;
Expand Down Expand Up @@ -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);
Expand All @@ -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;
}

Expand Down
78 changes: 54 additions & 24 deletions drivers/net/bonding/bond_main.c
View file
Expand Up @@ -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");
Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -2012,29 +2018,34 @@ 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;
}

if ((new_active) &&
(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;
}
Expand Down Expand Up @@ -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;
Expand Down Expand Up @@ -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);

Expand Down Expand Up @@ -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:
Expand Down Expand Up @@ -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)) {
Expand Down Expand Up @@ -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);
Expand Down Expand Up @@ -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;

Expand All @@ -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;
Expand Down

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