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Message-Id: <1405432616-12414-4-git-send-email-edumazet@google.com>
Date: Tue, 15 Jul 2014 06:56:55 -0700
From: Eric Dumazet <edumazet@...gle.com>
To: "David S. Miller" <davem@...emloft.net>
Cc: netdev@...r.kernel.org, Jay Vosburgh <j.vosburgh@...il.com>,
Veaceslav Falico <vfalico@...il.com>,
Andy Gospodarek <andy@...yhouse.net>,
Nikolay Aleksandrov <nikolay@...hat.com>,
Mahesh Bandewar <maheshb@...gle.com>,
Eric Dumazet <edumazet@...gle.com>
Subject: [PATCH v2 net-next 3/4] bonding: add proper __rcu annotation for curr_active_slave
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
are correctly protected, with LOCKDEP support.
Signed-off-by: Eric Dumazet <edumazet@...gle.com>
Acked-by: Veaceslav Falico <vfalico@...il.com>
Reviewed-by: Nikolay Aleksandrov <nikolay@...hat.com>
---
drivers/net/bonding/bond_alb.c | 47 +++++++++++++++++++--------------
drivers/net/bonding/bond_main.c | 53 +++++++++++++++++++++-----------------
drivers/net/bonding/bond_options.c | 2 +-
drivers/net/bonding/bonding.h | 6 ++++-
4 files changed, 63 insertions(+), 45 deletions(-)
diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index 76c0dade233f..de5bd03925b4 100644
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -448,11 +448,13 @@ 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;
@@ -460,7 +462,7 @@ static void rlb_teach_disabled_mac_on_primary(struct bonding *bond, u8 addr[])
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
@@ -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);
@@ -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);
@@ -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;
@@ -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);
@@ -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;
@@ -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();
@@ -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))
@@ -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;
@@ -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);
}
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 09dc3ef771a7..6a331bbcf43a 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -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;
@@ -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;
@@ -713,7 +713,7 @@ out:
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;
@@ -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;
@@ -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)
@@ -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;
@@ -1602,7 +1607,7 @@ err_detach:
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);
@@ -1704,7 +1709,7 @@ 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;
@@ -1878,7 +1883,7 @@ 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;
@@ -1886,7 +1891,7 @@ static int bond_miimon_inspect(struct bonding *bond)
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;
@@ -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;
@@ -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
@@ -2607,8 +2612,8 @@ 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))) {
slave->link = BOND_LINK_UP;
if (bond->current_arp_slave) {
@@ -2621,7 +2626,7 @@ static void bond_ab_arp_commit(struct bonding *bond)
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;
@@ -2640,7 +2645,7 @@ 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) {
+ if (slave == rtnl_dereference(bond->curr_active_slave)) {
bond->current_arp_slave = NULL;
goto do_failover;
}
@@ -3097,8 +3102,8 @@ 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 {
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
index b26271fd7b09..f908e65e86c1 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c
@@ -743,7 +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);
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index 713e2a99c661..d03d2ae4d3af 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -194,7 +194,7 @@ struct slave {
*/
struct bonding {
struct net_device *dev; /* first - useful for panic debug */
- struct slave *curr_active_slave;
+ struct slave __rcu *curr_active_slave;
struct slave *current_arp_slave;
struct slave *primary_slave;
bool force_primary;
@@ -232,6 +232,10 @@ struct bonding {
#define bond_slave_get_rtnl(dev) \
((struct slave *) rtnl_dereference(dev->rx_handler_data))
+#define bond_deref_active_protected(bond) \
+ rcu_dereference_protected(bond->curr_active_slave, \
+ lockdep_is_held(&bond->curr_slave_lock))
+
struct bond_vlan_tag {
__be16 vlan_proto;
unsigned short vlan_id;
--
2.0.0.526.g5318336
--
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