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Merge branch 'bonding_rcu'
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Eric Dumazet says:

====================
bonding: rcu cleanups

RCU was added to bonding in linux-3.12 but lacked proper sparse annotations.

Using __rcu annotation actually helps to spot all accesses to
bond->curr_active_slave & cond->current_arp_slave
are correctly protected, with full sparse & LOCKDEP support.

Lets clean the code.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
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@davem330
davem330 committed Jul 16, 2014
2 parents 725b701 + 8574171 commit c8ad0f2
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Showing 6 changed files with 91 additions and 64 deletions.
47 changes: 28 additions & 19 deletions drivers/net/bonding/bond_alb.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -448,19 +448,21 @@ static struct slave *__rlb_next_rx_slave(struct bonding *bond)
*/
static void rlb_teach_disabled_mac_on_primary(struct bonding *bond, u8 addr[])
{
if (!bond->curr_active_slave)
struct slave *curr_active = bond_deref_active_protected(bond);

if (!curr_active)
return;

if (!bond->alb_info.primary_is_promisc) {
if (!dev_set_promiscuity(bond->curr_active_slave->dev, 1))
if (!dev_set_promiscuity(curr_active->dev, 1))
bond->alb_info.primary_is_promisc = 1;
else
bond->alb_info.primary_is_promisc = 0;
}

bond->alb_info.rlb_promisc_timeout_counter = 0;

alb_send_learning_packets(bond->curr_active_slave, addr, true);
alb_send_learning_packets(curr_active, addr, true);
}

/* slave being removed should not be active at this point
Expand Down Expand Up @@ -509,7 +511,7 @@ static void rlb_clear_slave(struct bonding *bond, struct slave *slave)

write_lock_bh(&bond->curr_slave_lock);

if (slave != bond->curr_active_slave)
if (slave != bond_deref_active_protected(bond))
rlb_teach_disabled_mac_on_primary(bond, slave->dev->dev_addr);

write_unlock_bh(&bond->curr_slave_lock);
Expand Down Expand Up @@ -684,7 +686,7 @@ static struct slave *rlb_choose_channel(struct sk_buff *skb, struct bonding *bon
* move the old client to primary (curr_active_slave) so
* that the new client can be assigned to this entry.
*/
if (bond->curr_active_slave &&
if (curr_active_slave &&
client_info->slave != curr_active_slave) {
client_info->slave = curr_active_slave;
rlb_update_client(client_info);
Expand Down Expand Up @@ -1221,7 +1223,7 @@ static void alb_change_hw_addr_on_detach(struct bonding *bond, struct slave *sla
*/
static int alb_handle_addr_collision_on_attach(struct bonding *bond, struct slave *slave)
{
struct slave *has_bond_addr = bond->curr_active_slave;
struct slave *has_bond_addr = rcu_access_pointer(bond->curr_active_slave);
struct slave *tmp_slave1, *free_mac_slave = NULL;
struct list_head *iter;

Expand Down Expand Up @@ -1575,7 +1577,7 @@ void bond_alb_monitor(struct work_struct *work)
* use mac of the slave device.
* In RLB mode, we always use strict matches.
*/
strict_match = (slave != bond->curr_active_slave ||
strict_match = (slave != rcu_access_pointer(bond->curr_active_slave) ||
bond_info->rlb_enabled);
alb_send_learning_packets(slave, slave->dev->dev_addr,
strict_match);
Expand All @@ -1593,7 +1595,7 @@ void bond_alb_monitor(struct work_struct *work)

bond_for_each_slave_rcu(bond, slave, iter) {
tlb_clear_slave(bond, slave, 1);
if (slave == bond->curr_active_slave) {
if (slave == rcu_access_pointer(bond->curr_active_slave)) {
SLAVE_TLB_INFO(slave).load =
bond_info->unbalanced_load /
BOND_TLB_REBALANCE_INTERVAL;
Expand Down Expand Up @@ -1625,7 +1627,8 @@ void bond_alb_monitor(struct work_struct *work)
* because a slave was disabled then
* it can now leave promiscuous mode.
*/
dev_set_promiscuity(bond->curr_active_slave->dev, -1);
dev_set_promiscuity(rtnl_dereference(bond->curr_active_slave)->dev,
-1);
bond_info->primary_is_promisc = 0;

rtnl_unlock();
Expand Down Expand Up @@ -1742,17 +1745,21 @@ void bond_alb_handle_active_change(struct bonding *bond, struct slave *new_slave
__acquires(&bond->curr_slave_lock)
{
struct slave *swap_slave;
struct slave *curr_active;

if (bond->curr_active_slave == new_slave)
curr_active = rcu_dereference_protected(bond->curr_active_slave,
!new_slave ||
lockdep_is_held(&bond->curr_slave_lock));
if (curr_active == new_slave)
return;

if (bond->curr_active_slave && bond->alb_info.primary_is_promisc) {
dev_set_promiscuity(bond->curr_active_slave->dev, -1);
if (curr_active && bond->alb_info.primary_is_promisc) {
dev_set_promiscuity(curr_active->dev, -1);
bond->alb_info.primary_is_promisc = 0;
bond->alb_info.rlb_promisc_timeout_counter = 0;
}

swap_slave = bond->curr_active_slave;
swap_slave = curr_active;
rcu_assign_pointer(bond->curr_active_slave, new_slave);

if (!new_slave || !bond_has_slaves(bond))
Expand Down Expand Up @@ -1818,6 +1825,7 @@ int bond_alb_set_mac_address(struct net_device *bond_dev, void *addr)
{
struct bonding *bond = netdev_priv(bond_dev);
struct sockaddr *sa = addr;
struct slave *curr_active;
struct slave *swap_slave;
int res;

Expand All @@ -1834,23 +1842,24 @@ int bond_alb_set_mac_address(struct net_device *bond_dev, void *addr)
* Otherwise we'll need to pass the new address to it and handle
* duplications.
*/
if (!bond->curr_active_slave)
curr_active = rtnl_dereference(bond->curr_active_slave);
if (!curr_active)
return 0;

swap_slave = bond_slave_has_mac(bond, bond_dev->dev_addr);

if (swap_slave) {
alb_swap_mac_addr(swap_slave, bond->curr_active_slave);
alb_fasten_mac_swap(bond, swap_slave, bond->curr_active_slave);
alb_swap_mac_addr(swap_slave, curr_active);
alb_fasten_mac_swap(bond, swap_slave, curr_active);
} else {
alb_set_slave_mac_addr(bond->curr_active_slave, bond_dev->dev_addr);
alb_set_slave_mac_addr(curr_active, bond_dev->dev_addr);

read_lock(&bond->lock);
alb_send_learning_packets(bond->curr_active_slave,
alb_send_learning_packets(curr_active,
bond_dev->dev_addr, false);
if (bond->alb_info.rlb_enabled) {
/* inform clients mac address has changed */
rlb_req_update_slave_clients(bond, bond->curr_active_slave);
rlb_req_update_slave_clients(bond, curr_active);
}
read_unlock(&bond->lock);
}
Expand Down
68 changes: 38 additions & 30 deletions drivers/net/bonding/bond_main.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -498,11 +498,11 @@ static int bond_set_promiscuity(struct bonding *bond, int inc)
int err = 0;

if (bond_uses_primary(bond)) {
struct slave *curr_active = bond_deref_active_protected(bond);

/* write lock already acquired */
if (bond->curr_active_slave) {
err = dev_set_promiscuity(bond->curr_active_slave->dev,
inc);
}
if (curr_active)
err = dev_set_promiscuity(curr_active->dev, inc);
} else {
struct slave *slave;

Expand All @@ -524,11 +524,11 @@ static int bond_set_allmulti(struct bonding *bond, int inc)
int err = 0;

if (bond_uses_primary(bond)) {
struct slave *curr_active = bond_deref_active_protected(bond);

/* write lock already acquired */
if (bond->curr_active_slave) {
err = dev_set_allmulti(bond->curr_active_slave->dev,
inc);
}
if (curr_active)
err = dev_set_allmulti(curr_active->dev, inc);
} else {
struct slave *slave;

Expand Down Expand Up @@ -713,7 +713,7 @@ static void bond_do_fail_over_mac(struct bonding *bond,
static bool bond_should_change_active(struct bonding *bond)
{
struct slave *prim = bond->primary_slave;
struct slave *curr = bond->curr_active_slave;
struct slave *curr = bond_deref_active_protected(bond);

if (!prim || !curr || curr->link != BOND_LINK_UP)
return true;
Expand Down Expand Up @@ -792,7 +792,11 @@ static bool bond_should_notify_peers(struct bonding *bond)
*/
void bond_change_active_slave(struct bonding *bond, struct slave *new_active)
{
struct slave *old_active = bond->curr_active_slave;
struct slave *old_active;

old_active = rcu_dereference_protected(bond->curr_active_slave,
!new_active ||
lockdep_is_held(&bond->curr_slave_lock));

if (old_active == new_active)
return;
Expand Down Expand Up @@ -900,7 +904,7 @@ void bond_select_active_slave(struct bonding *bond)
int rv;

best_slave = bond_find_best_slave(bond);
if (best_slave != bond->curr_active_slave) {
if (best_slave != bond_deref_active_protected(bond)) {
bond_change_active_slave(bond, best_slave);
rv = bond_set_carrier(bond);
if (!rv)
Expand Down Expand Up @@ -1531,7 +1535,8 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
* anyway (it holds no special properties of the bond device),
* so we can change it without calling change_active_interface()
*/
if (!bond->curr_active_slave && new_slave->link == BOND_LINK_UP)
if (!rcu_access_pointer(bond->curr_active_slave) &&
new_slave->link == BOND_LINK_UP)
rcu_assign_pointer(bond->curr_active_slave, new_slave);

break;
Expand Down Expand Up @@ -1602,7 +1607,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
vlan_vids_del_by_dev(slave_dev, bond_dev);
if (bond->primary_slave == new_slave)
bond->primary_slave = NULL;
if (bond->curr_active_slave == new_slave) {
if (rcu_access_pointer(bond->curr_active_slave) == new_slave) {
block_netpoll_tx();
write_lock_bh(&bond->curr_slave_lock);
bond_change_active_slave(bond, NULL);
Expand Down Expand Up @@ -1704,9 +1709,9 @@ static int __bond_release_one(struct net_device *bond_dev,
bond_is_active_slave(slave) ? "active" : "backup",
slave_dev->name);

oldcurrent = bond->curr_active_slave;
oldcurrent = rcu_access_pointer(bond->curr_active_slave);

bond->current_arp_slave = NULL;
RCU_INIT_POINTER(bond->current_arp_slave, NULL);

if (!all && (!bond->params.fail_over_mac ||
BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP)) {
Expand Down Expand Up @@ -1878,15 +1883,15 @@ static int bond_slave_info_query(struct net_device *bond_dev, struct ifslave *in

/*-------------------------------- Monitoring -------------------------------*/


/* called with rcu_read_lock() */
static int bond_miimon_inspect(struct bonding *bond)
{
int link_state, commit = 0;
struct list_head *iter;
struct slave *slave;
bool ignore_updelay;

ignore_updelay = !bond->curr_active_slave ? true : false;
ignore_updelay = !rcu_dereference(bond->curr_active_slave);

bond_for_each_slave_rcu(bond, slave, iter) {
slave->new_link = BOND_LINK_NOCHANGE;
Expand Down Expand Up @@ -2046,7 +2051,7 @@ static void bond_miimon_commit(struct bonding *bond)
bond_alb_handle_link_change(bond, slave,
BOND_LINK_DOWN);

if (slave == bond->curr_active_slave)
if (slave == rcu_access_pointer(bond->curr_active_slave))
goto do_failover;

continue;
Expand Down Expand Up @@ -2416,7 +2421,7 @@ static void bond_loadbalance_arp_mon(struct work_struct *work)

rcu_read_lock();

oldcurrent = ACCESS_ONCE(bond->curr_active_slave);
oldcurrent = rcu_dereference(bond->curr_active_slave);
/* see if any of the previous devices are up now (i.e. they have
* xmt and rcv traffic). the curr_active_slave does not come into
* the picture unless it is null. also, slave->last_link_up is not
Expand Down Expand Up @@ -2564,7 +2569,7 @@ static int bond_ab_arp_inspect(struct bonding *bond)
* before being taken out
*/
if (!bond_is_active_slave(slave) &&
!bond->current_arp_slave &&
!rcu_access_pointer(bond->current_arp_slave) &&
!bond_time_in_interval(bond, last_rx, 3)) {
slave->new_link = BOND_LINK_DOWN;
commit++;
Expand Down Expand Up @@ -2607,21 +2612,24 @@ static void bond_ab_arp_commit(struct bonding *bond)

case BOND_LINK_UP:
trans_start = dev_trans_start(slave->dev);
if (bond->curr_active_slave != slave ||
(!bond->curr_active_slave &&
if (rtnl_dereference(bond->curr_active_slave) != slave ||
(!rtnl_dereference(bond->curr_active_slave) &&
bond_time_in_interval(bond, trans_start, 1))) {
struct slave *current_arp_slave;

current_arp_slave = rtnl_dereference(bond->current_arp_slave);
slave->link = BOND_LINK_UP;
if (bond->current_arp_slave) {
if (current_arp_slave) {
bond_set_slave_inactive_flags(
bond->current_arp_slave,
current_arp_slave,
BOND_SLAVE_NOTIFY_NOW);
bond->current_arp_slave = NULL;
RCU_INIT_POINTER(bond->current_arp_slave, NULL);
}

pr_info("%s: link status definitely up for interface %s\n",
bond->dev->name, slave->dev->name);

if (!bond->curr_active_slave ||
if (!rtnl_dereference(bond->curr_active_slave) ||
(slave == bond->primary_slave))
goto do_failover;

Expand All @@ -2640,8 +2648,8 @@ static void bond_ab_arp_commit(struct bonding *bond)
pr_info("%s: link status definitely down for interface %s, disabling it\n",
bond->dev->name, slave->dev->name);

if (slave == bond->curr_active_slave) {
bond->current_arp_slave = NULL;
if (slave == rtnl_dereference(bond->curr_active_slave)) {
RCU_INIT_POINTER(bond->current_arp_slave, NULL);
goto do_failover;
}

Expand Down Expand Up @@ -3097,8 +3105,8 @@ static int bond_open(struct net_device *bond_dev)
if (bond_has_slaves(bond)) {
read_lock(&bond->curr_slave_lock);
bond_for_each_slave(bond, slave, iter) {
if (bond_uses_primary(bond)
&& (slave != bond->curr_active_slave)) {
if (bond_uses_primary(bond) &&
slave != rcu_access_pointer(bond->curr_active_slave)) {
bond_set_slave_inactive_flags(slave,
BOND_SLAVE_NOTIFY_NOW);
} else {
Expand Down
21 changes: 16 additions & 5 deletions drivers/net/bonding/bond_netlink.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -398,20 +398,31 @@ static size_t bond_get_size(const struct net_device *bond_dev)
0;
}

static int bond_option_active_slave_get_ifindex(struct bonding *bond)
{
const struct net_device *slave;
int ifindex;

rcu_read_lock();
slave = bond_option_active_slave_get_rcu(bond);
ifindex = slave ? slave->ifindex : 0;
rcu_read_unlock();
return ifindex;
}

static int bond_fill_info(struct sk_buff *skb,
const struct net_device *bond_dev)
{
struct bonding *bond = netdev_priv(bond_dev);
struct net_device *slave_dev = bond_option_active_slave_get(bond);
struct nlattr *targets;
unsigned int packets_per_slave;
int i, targets_added;
int ifindex, i, targets_added;
struct nlattr *targets;

if (nla_put_u8(skb, IFLA_BOND_MODE, BOND_MODE(bond)))
goto nla_put_failure;

if (slave_dev &&
nla_put_u32(skb, IFLA_BOND_ACTIVE_SLAVE, slave_dev->ifindex))
ifindex = bond_option_active_slave_get_ifindex(bond);
if (ifindex && nla_put_u32(skb, IFLA_BOND_ACTIVE_SLAVE, ifindex))
goto nla_put_failure;

if (nla_put_u32(skb, IFLA_BOND_MIIMON, bond->params.miimon))
Expand Down
7 changes: 1 addition & 6 deletions drivers/net/bonding/bond_options.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -704,11 +704,6 @@ struct net_device *bond_option_active_slave_get_rcu(struct bonding *bond)
return __bond_option_active_slave_get(bond, slave);
}

struct net_device *bond_option_active_slave_get(struct bonding *bond)
{
return __bond_option_active_slave_get(bond, bond->curr_active_slave);
}

static int bond_option_active_slave_set(struct bonding *bond,
const struct bond_opt_value *newval)
{
Expand Down Expand Up @@ -748,7 +743,7 @@ static int bond_option_active_slave_set(struct bonding *bond,
RCU_INIT_POINTER(bond->curr_active_slave, NULL);
bond_select_active_slave(bond);
} else {
struct slave *old_active = bond->curr_active_slave;
struct slave *old_active = bond_deref_active_protected(bond);
struct slave *new_active = bond_slave_get_rtnl(slave_dev);

BUG_ON(!new_active);
Expand Down
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