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Message-Id: <1410011971-24922-4-git-send-email-nikolay@redhat.com>
Date: Sat, 6 Sep 2014 15:59:28 +0200
From: Nikolay Aleksandrov <nikolay@...hat.com>
To: netdev@...r.kernel.org
Cc: vfalico@...il.com, j.vosburgh@...il.com, andy@...yhouse.net,
davem@...emloft.net, Nikolay Aleksandrov <nikolay@...hat.com>
Subject: [PATCH net-next 3/6] bonding: convert primary_slave to use RCU
This is necessary mainly for two bonding call sites: procfs and
sysfs as it was dereferenced without any real protection.
Signed-off-by: Nikolay Aleksandrov <nikolay@...hat.com>
---
Some of the primary_slave change sites could use RCU_INIT_POINTER() instead
of rcu_assign_pointer as they don't need the barriers, but I've left it
like this to clearly show the intention, in case this is a problem we can
always switch them to RCU_INIT_POINTER().
drivers/net/bonding/bond_main.c | 42 +++++++++++++++++++++-----------------
drivers/net/bonding/bond_netlink.c | 7 ++++---
drivers/net/bonding/bond_options.c | 8 ++++----
drivers/net/bonding/bond_procfs.c | 8 ++++----
drivers/net/bonding/bond_sysfs.c | 10 ++++++---
drivers/net/bonding/bonding.h | 2 +-
6 files changed, 43 insertions(+), 34 deletions(-)
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index dcd331bd0c17..629037f79213 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -708,7 +708,7 @@ out:
static bool bond_should_change_active(struct bonding *bond)
{
- struct slave *prim = bond->primary_slave;
+ struct slave *prim = rtnl_dereference(bond->primary_slave);
struct slave *curr = bond_deref_active_protected(bond);
if (!prim || !curr || curr->link != BOND_LINK_UP)
@@ -732,13 +732,14 @@ static bool bond_should_change_active(struct bonding *bond)
*/
static struct slave *bond_find_best_slave(struct bonding *bond)
{
- struct slave *slave, *bestslave = NULL;
+ struct slave *slave, *bestslave = NULL, *primary;
struct list_head *iter;
int mintime = bond->params.updelay;
- if (bond->primary_slave && bond->primary_slave->link == BOND_LINK_UP &&
+ primary = rtnl_dereference(bond->primary_slave);
+ if (primary && primary->link == BOND_LINK_UP &&
bond_should_change_active(bond))
- return bond->primary_slave;
+ return primary;
bond_for_each_slave(bond, slave, iter) {
if (slave->link == BOND_LINK_UP)
@@ -1482,7 +1483,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
if (bond_uses_primary(bond) && bond->params.primary[0]) {
/* if there is a primary slave, remember it */
if (strcmp(bond->params.primary, new_slave->dev->name) == 0) {
- bond->primary_slave = new_slave;
+ rcu_assign_pointer(bond->primary_slave, new_slave);
bond->force_primary = true;
}
}
@@ -1596,8 +1597,8 @@ err_detach:
bond_hw_addr_flush(bond_dev, slave_dev);
vlan_vids_del_by_dev(slave_dev, bond_dev);
- if (bond->primary_slave == new_slave)
- bond->primary_slave = NULL;
+ if (rcu_access_pointer(bond->primary_slave) == new_slave)
+ RCU_INIT_POINTER(bond->primary_slave, NULL);
if (rcu_access_pointer(bond->curr_active_slave) == new_slave) {
block_netpoll_tx();
write_lock_bh(&bond->curr_slave_lock);
@@ -1606,6 +1607,8 @@ err_detach:
write_unlock_bh(&bond->curr_slave_lock);
unblock_netpoll_tx();
}
+ /* either primary_slave or curr_active_slave might've changed */
+ synchronize_rcu();
slave_disable_netpoll(new_slave);
err_close:
@@ -1714,8 +1717,8 @@ static int __bond_release_one(struct net_device *bond_dev,
bond_dev->name, slave_dev->name);
}
- if (bond->primary_slave == slave)
- bond->primary_slave = NULL;
+ if (rtnl_dereference(bond->primary_slave) == slave)
+ RCU_INIT_POINTER(bond->primary_slave, NULL);
if (oldcurrent == slave) {
write_lock_bh(&bond->curr_slave_lock);
@@ -1976,7 +1979,7 @@ static int bond_miimon_inspect(struct bonding *bond)
static void bond_miimon_commit(struct bonding *bond)
{
struct list_head *iter;
- struct slave *slave;
+ struct slave *slave, *primary;
bond_for_each_slave(bond, slave, iter) {
switch (slave->new_link) {
@@ -1987,13 +1990,14 @@ static void bond_miimon_commit(struct bonding *bond)
slave->link = BOND_LINK_UP;
slave->last_link_up = jiffies;
+ primary = rtnl_dereference(bond->primary_slave);
if (BOND_MODE(bond) == BOND_MODE_8023AD) {
/* prevent it from being the active one */
bond_set_backup_slave(slave);
} else if (BOND_MODE(bond) != BOND_MODE_ACTIVEBACKUP) {
/* make it immediately active */
bond_set_active_slave(slave);
- } else if (slave != bond->primary_slave) {
+ } else if (slave != primary) {
/* prevent it from being the active one */
bond_set_backup_slave(slave);
}
@@ -2011,8 +2015,7 @@ static void bond_miimon_commit(struct bonding *bond)
bond_alb_handle_link_change(bond, slave,
BOND_LINK_UP);
- if (!bond->curr_active_slave ||
- (slave == bond->primary_slave))
+ if (!bond->curr_active_slave || slave == primary)
goto do_failover;
continue;
@@ -2633,7 +2636,7 @@ static void bond_ab_arp_commit(struct bonding *bond)
slave->dev->name);
if (!rtnl_dereference(bond->curr_active_slave) ||
- (slave == bond->primary_slave))
+ slave == rtnl_dereference(bond->primary_slave))
goto do_failover;
}
@@ -2860,7 +2863,7 @@ static int bond_master_netdev_event(unsigned long event,
static int bond_slave_netdev_event(unsigned long event,
struct net_device *slave_dev)
{
- struct slave *slave = bond_slave_get_rtnl(slave_dev);
+ struct slave *slave = bond_slave_get_rtnl(slave_dev), *primary;
struct bonding *bond;
struct net_device *bond_dev;
u32 old_speed;
@@ -2874,6 +2877,7 @@ static int bond_slave_netdev_event(unsigned long event,
return NOTIFY_DONE;
bond_dev = slave->bond->dev;
bond = slave->bond;
+ primary = rtnl_dereference(bond->primary_slave);
switch (event) {
case NETDEV_UNREGISTER:
@@ -2921,18 +2925,18 @@ static int bond_slave_netdev_event(unsigned long event,
!bond->params.primary[0])
break;
- if (slave == bond->primary_slave) {
+ if (slave == primary) {
/* slave's name changed - he's no longer primary */
- bond->primary_slave = NULL;
+ RCU_INIT_POINTER(bond->primary_slave, NULL);
} else if (!strcmp(slave_dev->name, bond->params.primary)) {
/* we have a new primary slave */
- bond->primary_slave = slave;
+ rcu_assign_pointer(bond->primary_slave, slave);
} else { /* we didn't change primary - exit */
break;
}
netdev_info(bond->dev, "Primary slave changed to %s, reselecting active slave\n",
- bond->primary_slave ? slave_dev->name : "none");
+ primary ? slave_dev->name : "none");
block_netpoll_tx();
write_lock_bh(&bond->curr_slave_lock);
diff --git a/drivers/net/bonding/bond_netlink.c b/drivers/net/bonding/bond_netlink.c
index e1489d9df2a4..c13d83e15ace 100644
--- a/drivers/net/bonding/bond_netlink.c
+++ b/drivers/net/bonding/bond_netlink.c
@@ -443,6 +443,7 @@ static int bond_fill_info(struct sk_buff *skb,
unsigned int packets_per_slave;
int ifindex, i, targets_added;
struct nlattr *targets;
+ struct slave *primary;
if (nla_put_u8(skb, IFLA_BOND_MODE, BOND_MODE(bond)))
goto nla_put_failure;
@@ -492,9 +493,9 @@ static int bond_fill_info(struct sk_buff *skb,
bond->params.arp_all_targets))
goto nla_put_failure;
- if (bond->primary_slave &&
- nla_put_u32(skb, IFLA_BOND_PRIMARY,
- bond->primary_slave->dev->ifindex))
+ primary = rtnl_dereference(bond->primary_slave);
+ if (primary &&
+ nla_put_u32(skb, IFLA_BOND_PRIMARY, primary->dev->ifindex))
goto nla_put_failure;
if (nla_put_u8(skb, IFLA_BOND_PRIMARY_RESELECT,
diff --git a/drivers/net/bonding/bond_options.c b/drivers/net/bonding/bond_options.c
index d8dc17faa6b4..7c9e176baecc 100644
--- a/drivers/net/bonding/bond_options.c
+++ b/drivers/net/bonding/bond_options.c
@@ -1090,7 +1090,7 @@ static int bond_option_primary_set(struct bonding *bond,
/* check to see if we are clearing primary */
if (!strlen(primary)) {
netdev_info(bond->dev, "Setting primary slave to None\n");
- bond->primary_slave = NULL;
+ RCU_INIT_POINTER(bond->primary_slave, NULL);
memset(bond->params.primary, 0, sizeof(bond->params.primary));
bond_select_active_slave(bond);
goto out;
@@ -1100,16 +1100,16 @@ static int bond_option_primary_set(struct bonding *bond,
if (strncmp(slave->dev->name, primary, IFNAMSIZ) == 0) {
netdev_info(bond->dev, "Setting %s as primary slave\n",
slave->dev->name);
- bond->primary_slave = slave;
+ rcu_assign_pointer(bond->primary_slave, slave);
strcpy(bond->params.primary, slave->dev->name);
bond_select_active_slave(bond);
goto out;
}
}
- if (bond->primary_slave) {
+ if (rtnl_dereference(bond->primary_slave)) {
netdev_info(bond->dev, "Setting primary slave to None\n");
- bond->primary_slave = NULL;
+ RCU_INIT_POINTER(bond->primary_slave, NULL);
bond_select_active_slave(bond);
}
strncpy(bond->params.primary, primary, IFNAMSIZ);
diff --git a/drivers/net/bonding/bond_procfs.c b/drivers/net/bonding/bond_procfs.c
index de62c0385dfb..1a9fe1ba4c60 100644
--- a/drivers/net/bonding/bond_procfs.c
+++ b/drivers/net/bonding/bond_procfs.c
@@ -66,7 +66,7 @@ static void bond_info_show_master(struct seq_file *seq)
{
struct bonding *bond = seq->private;
const struct bond_opt_value *optval;
- struct slave *curr;
+ struct slave *curr, *primary;
int i;
curr = rcu_dereference(bond->curr_active_slave);
@@ -92,10 +92,10 @@ static void bond_info_show_master(struct seq_file *seq)
}
if (bond_uses_primary(bond)) {
+ primary = rcu_dereference(bond->primary_slave);
seq_printf(seq, "Primary Slave: %s",
- (bond->primary_slave) ?
- bond->primary_slave->dev->name : "None");
- if (bond->primary_slave) {
+ primary ? primary->dev->name : "None");
+ if (primary) {
optval = bond_opt_get_val(BOND_OPT_PRIMARY_RESELECT,
bond->params.primary_reselect);
seq_printf(seq, " (primary_reselect %s)",
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index 98db8edd9c75..5555517284db 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -425,11 +425,15 @@ static ssize_t bonding_show_primary(struct device *d,
struct device_attribute *attr,
char *buf)
{
- int count = 0;
struct bonding *bond = to_bond(d);
+ struct slave *primary;
+ int count = 0;
- if (bond->primary_slave)
- count = sprintf(buf, "%s\n", bond->primary_slave->dev->name);
+ rcu_read_lock();
+ primary = rcu_dereference(bond->primary_slave);
+ if (primary)
+ count = sprintf(buf, "%s\n", primary->dev->name);
+ rcu_read_unlock();
return count;
}
diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
index aace510d08d1..c798561a6f01 100644
--- a/drivers/net/bonding/bonding.h
+++ b/drivers/net/bonding/bonding.h
@@ -195,7 +195,7 @@ struct bonding {
struct net_device *dev; /* first - useful for panic debug */
struct slave __rcu *curr_active_slave;
struct slave __rcu *current_arp_slave;
- struct slave *primary_slave;
+ struct slave __rcu *primary_slave;
bool force_primary;
s32 slave_cnt; /* never change this value outside the attach/detach wrappers */
int (*recv_probe)(const struct sk_buff *, struct bonding *,
--
1.9.3
--
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