@@ -66,6 +66,7 @@ struct net {
struct hlist_head *dev_name_head;
struct hlist_head *dev_index_head;
unsigned int dev_base_seq; /* protected by rtnl_mutex */
+ int ifindex;
/* core fib_rules */
struct list_head rules_ops;
@@ -5221,12 +5221,12 @@ int dev_ioctl(struct net *net, unsigned int cmd, void __user *arg)
*/
static int dev_new_index(struct net *net)
{
- static int ifindex;
+ int ifindex = net->ifindex;
for (;;) {
if (++ifindex <= 0)
ifindex = 1;
if (!__dev_get_by_index(net, ifindex))
- return ifindex;
+ return net->ifindex = ifindex;
}
}
Strictly speaking this is only _really_ required for checkpoint-restore to make loopback device always have the same index. This change appears to be safe wrt "ifindex should be unique per-system" concept, as all the ifindex usage is either already made per net namespace of is explicitly limited with init_net only. There are two cool side effects of this. The first one -- ifindices of devices in container are always small, regardless of how many containers we've started (and re-started) so far. The second one is -- we can speed up the loopback ifidex access as shown in the next patch. v2: Place ifindex right after dev_base_seq : avoid two holes and use the same cache line, dirtied in list_netdevice()/unlist_netdevice() Signed-off-by: Pavel Emelyanov <xemul@parallels.com> Acked-by: Eric Dumazet <edumazet@google.com> --- include/net/net_namespace.h | 1 + net/core/dev.c | 4 ++-- 2 files changed, 3 insertions(+), 2 deletions(-)