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Message-Id: <1375283553-32070-6-git-send-email-nikolay@redhat.com>
Date: Wed, 31 Jul 2013 17:12:33 +0200
From: Nikolay Aleksandrov <nikolay@...hat.com>
To: netdev@...r.kernel.org
Cc: andy@...yhouse.net, davem@...emloft.net, fubar@...ibm.com
Subject: [PATCH net-next 5/5] bonding: initial RCU conversion
This patch does the initial bonding conversion to RCU. After it the
following modes are protected by RCU alone: roundrobin, active-backup,
broadcast and xor. Modes ALB/TLB and 3ad still acquire bond->lock for
reading, and will be dealt with later. curr_active_slave needs to be
dereferenced via rcu in the converted modes because the only thing
protecting the slave after this patch is rcu_read_lock, so we need the
proper barrier for weakly ordered archs and to make sure we don't have
stale pointer. It's not tagged with __rcu yet because there's still work
to be done to remove the curr_slave_lock, so sparse will complain when
rcu_assign_pointer and rcu_dereference are used, but the alternative to use
rcu_dereference_protected would've created much bigger code churn which is
more difficult to test and review. That will be converted in time.
Signed-off-by: Nikolay Aleksandrov <nikolay@...hat.com>
---
drivers/net/bonding/bond_3ad.c | 2 ++
drivers/net/bonding/bond_alb.c | 6 ++++--
drivers/net/bonding/bond_main.c | 30 +++++++++++++++---------------
drivers/net/bonding/bond_sysfs.c | 2 +-
4 files changed, 22 insertions(+), 18 deletions(-)
diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
index 80e288c..bb25aa1 100644
--- a/drivers/net/bonding/bond_3ad.c
+++ b/drivers/net/bonding/bond_3ad.c
@@ -2424,6 +2424,7 @@ int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev)
struct ad_info ad_info;
int res = 1;
+ read_lock(&bond->lock);
if (__bond_3ad_get_active_agg_info(bond, &ad_info)) {
pr_debug("%s: Error: __bond_3ad_get_active_agg_info failed\n",
dev->name);
@@ -2473,6 +2474,7 @@ int bond_3ad_xmit_xor(struct sk_buff *skb, struct net_device *dev)
}
out:
+ read_unlock(&bond->lock);
if (res) {
/* no suitable interface, frame not sent */
kfree_skb(skb);
diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c
index 41889e3..8f52789 100644
--- a/drivers/net/bonding/bond_alb.c
+++ b/drivers/net/bonding/bond_alb.c
@@ -1337,6 +1337,7 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
/* make sure that the curr_active_slave do not change during tx
*/
+ read_lock(&bond->lock);
read_lock(&bond->curr_slave_lock);
switch (ntohs(skb->protocol)) {
@@ -1441,11 +1442,12 @@ int bond_alb_xmit(struct sk_buff *skb, struct net_device *bond_dev)
}
read_unlock(&bond->curr_slave_lock);
-
+ read_unlock(&bond->lock);
if (res) {
/* no suitable interface, frame not sent */
kfree_skb(skb);
}
+
return NETDEV_TX_OK;
}
@@ -1665,7 +1667,7 @@ void bond_alb_handle_active_change(struct bonding *bond, struct slave *new_slave
}
swap_slave = bond->curr_active_slave;
- bond->curr_active_slave = new_slave;
+ rcu_assign_pointer(bond->curr_active_slave, new_slave);
if (!new_slave || (bond->slave_cnt == 0)) {
return;
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 45ed9b1..126cb50 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -77,6 +77,7 @@
#include <net/net_namespace.h>
#include <net/netns/generic.h>
#include <net/pkt_sched.h>
+#include <linux/rculist.h>
#include "bonding.h"
#include "bond_3ad.h"
#include "bond_alb.h"
@@ -1038,7 +1039,7 @@ void bond_change_active_slave(struct bonding *bond, struct slave *new_active)
if (new_active)
bond_set_slave_active_flags(new_active);
} else {
- bond->curr_active_slave = new_active;
+ rcu_assign_pointer(bond->curr_active_slave, new_active);
}
if (bond->params.mode == BOND_MODE_ACTIVEBACKUP) {
@@ -1128,7 +1129,7 @@ void bond_select_active_slave(struct bonding *bond)
*/
static void bond_attach_slave(struct bonding *bond, struct slave *new_slave)
{
- list_add_tail(&new_slave->list, &bond->slave_list);
+ list_add_tail_rcu(&new_slave->list, &bond->slave_list);
bond->slave_cnt++;
}
@@ -1144,7 +1145,7 @@ static void bond_attach_slave(struct bonding *bond, struct slave *new_slave)
*/
static void bond_detach_slave(struct bonding *bond, struct slave *slave)
{
- list_del(&slave->list);
+ list_del_rcu(&slave->list);
bond->slave_cnt--;
}
@@ -1751,7 +1752,7 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
* so we can change it without calling change_active_interface()
*/
if (!bond->curr_active_slave && new_slave->link == BOND_LINK_UP)
- bond->curr_active_slave = new_slave;
+ rcu_assign_pointer(bond->curr_active_slave, new_slave);
break;
} /* switch(bond_mode) */
@@ -1951,7 +1952,7 @@ static int __bond_release_one(struct net_device *bond_dev,
}
if (all) {
- bond->curr_active_slave = NULL;
+ rcu_assign_pointer(bond->curr_active_slave, NULL);
} else if (oldcurrent == slave) {
/*
* Note that we hold RTNL over this sequence, so there
@@ -1982,6 +1983,7 @@ static int __bond_release_one(struct net_device *bond_dev,
}
write_unlock_bh(&bond->lock);
+ synchronize_rcu();
unblock_netpoll_tx();
if (bond->slave_cnt == 0) {
@@ -3817,7 +3819,7 @@ void bond_xmit_slave_id(struct bonding *bond, struct sk_buff *skb, int slave_id)
int i = slave_id;
/* Here we start from the slave with slave_id */
- list_for_each_entry(slave, &bond->slave_list, list) {
+ list_for_each_entry_rcu(slave, &bond->slave_list, list) {
if (--i < 0) {
if (slave_can_tx(slave)) {
bond_dev_queue_xmit(bond, skb, slave->dev);
@@ -3828,7 +3830,7 @@ void bond_xmit_slave_id(struct bonding *bond, struct sk_buff *skb, int slave_id)
/* Here we start from the first slave up to slave_id */
i = slave_id;
- list_for_each_entry(slave, &bond->slave_list, list) {
+ list_for_each_entry_rcu(slave, &bond->slave_list, list) {
if (--i < 0)
break;
if (slave_can_tx(slave)) {
@@ -3854,7 +3856,7 @@ static int bond_xmit_roundrobin(struct sk_buff *skb, struct net_device *bond_dev
* will send all of this type of traffic.
*/
if (iph->protocol == IPPROTO_IGMP && skb->protocol == htons(ETH_P_IP)) {
- slave = bond->curr_active_slave;
+ slave = rcu_dereference(bond->curr_active_slave);
if (slave && slave_can_tx(slave))
bond_dev_queue_xmit(bond, skb, slave->dev);
else
@@ -3876,7 +3878,7 @@ static int bond_xmit_activebackup(struct sk_buff *skb, struct net_device *bond_d
struct bonding *bond = netdev_priv(bond_dev);
struct slave *slave;
- slave = bond->curr_active_slave;
+ slave = rcu_dereference(bond->curr_active_slave);
if (slave)
bond_dev_queue_xmit(bond, skb, slave->dev);
else
@@ -3906,7 +3908,7 @@ static int bond_xmit_broadcast(struct sk_buff *skb, struct net_device *bond_dev)
struct bonding *bond = netdev_priv(bond_dev);
struct slave *slave = NULL;
- list_for_each_entry(slave, &bond->slave_list, list) {
+ list_for_each_entry_rcu(slave, &bond->slave_list, list) {
if (slave->list.next == &bond->slave_list)
break;
if (IS_UP(slave->dev) && slave->link == BOND_LINK_UP) {
@@ -3961,7 +3963,7 @@ static inline int bond_slave_override(struct bonding *bond,
return 1;
/* Find out if any slaves have the same mapping as this skb. */
- list_for_each_entry(check_slave, &bond->slave_list, list) {
+ list_for_each_entry_rcu(check_slave, &bond->slave_list, list) {
if (check_slave->queue_id == skb->queue_mapping) {
slave = check_slave;
break;
@@ -4046,14 +4048,12 @@ static netdev_tx_t bond_start_xmit(struct sk_buff *skb, struct net_device *dev)
if (is_netpoll_tx_blocked(dev))
return NETDEV_TX_BUSY;
- read_lock(&bond->lock);
-
+ rcu_read_lock();
if (bond->slave_cnt)
ret = __bond_start_xmit(skb, dev);
else
kfree_skb(skb);
-
- read_unlock(&bond->lock);
+ rcu_read_unlock();
return ret;
}
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index a19b163..3102926 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -1284,7 +1284,7 @@ static ssize_t bonding_store_active_slave(struct device *d,
if (!strlen(ifname) || buf[0] == '\n') {
pr_info("%s: Clearing current active slave.\n",
bond->dev->name);
- bond->curr_active_slave = NULL;
+ rcu_assign_pointer(bond->curr_active_slave, NULL);
bond_select_active_slave(bond);
goto out;
}
--
1.8.1.4
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