net: Introduce for_each_netdev_rcu() iterator
Adds RCU management to the list of netdevices.
Convert some for_each_netdev() users to RCU version, if
it can avoid read_lock-ing dev_base_lock
Ie:
read_lock(&dev_base_loack);
for_each_netdev(net, dev)
some_action();
read_unlock(&dev_base_lock);
becomes :
rcu_read_lock();
for_each_netdev_rcu(net, dev)
some_action();
rcu_read_unlock();
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index ccccaae..8aa7a13 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -876,19 +876,16 @@
if (!addr)
addr = ifa->ifa_local;
} endfor_ifa(in_dev);
-no_in_dev:
- rcu_read_unlock();
+no_in_dev:
if (addr)
- goto out;
+ goto out_unlock;
/* Not loopback addresses on loopback should be preferred
in this case. It is importnat that lo is the first interface
in dev_base list.
*/
- read_lock(&dev_base_lock);
- rcu_read_lock();
- for_each_netdev(net, dev) {
+ for_each_netdev_rcu(net, dev) {
if ((in_dev = __in_dev_get_rcu(dev)) == NULL)
continue;
@@ -896,12 +893,11 @@
if (ifa->ifa_scope != RT_SCOPE_LINK &&
ifa->ifa_scope <= scope) {
addr = ifa->ifa_local;
- goto out_unlock_both;
+ goto out_unlock;
}
} endfor_ifa(in_dev);
}
-out_unlock_both:
- read_unlock(&dev_base_lock);
+out_unlock:
rcu_read_unlock();
out:
return addr;
@@ -962,9 +958,8 @@
return confirm_addr_indev(in_dev, dst, local, scope);
net = dev_net(in_dev->dev);
- read_lock(&dev_base_lock);
rcu_read_lock();
- for_each_netdev(net, dev) {
+ for_each_netdev_rcu(net, dev) {
if ((in_dev = __in_dev_get_rcu(dev))) {
addr = confirm_addr_indev(in_dev, dst, local, scope);
if (addr)
@@ -972,7 +967,6 @@
}
}
rcu_read_unlock();
- read_unlock(&dev_base_lock);
return addr;
}
@@ -1240,18 +1234,18 @@
{
struct net_device *dev;
- read_lock(&dev_base_lock);
- for_each_netdev(net, dev) {
+ rcu_read_lock();
+ for_each_netdev_rcu(net, dev) {
struct in_device *in_dev;
- rcu_read_lock();
+
in_dev = __in_dev_get_rcu(dev);
if (in_dev && !test_bit(i, in_dev->cnf.state))
in_dev->cnf.data[i] = net->ipv4.devconf_dflt->data[i];
- rcu_read_unlock();
}
- read_unlock(&dev_base_lock);
+ rcu_read_unlock();
}
+/* called with RTNL locked */
static void inet_forward_change(struct net *net)
{
struct net_device *dev;
@@ -1260,7 +1254,6 @@
IPV4_DEVCONF_ALL(net, ACCEPT_REDIRECTS) = !on;
IPV4_DEVCONF_DFLT(net, FORWARDING) = on;
- read_lock(&dev_base_lock);
for_each_netdev(net, dev) {
struct in_device *in_dev;
if (on)
@@ -1271,7 +1264,6 @@
IN_DEV_CONF_SET(in_dev, FORWARDING, on);
rcu_read_unlock();
}
- read_unlock(&dev_base_lock);
}
static int devinet_conf_proc(ctl_table *ctl, int write,