net: dynamic ingress_queue allocation

ingress being not used very much, and net_device->ingress_queue being
quite a big object (128 or 256 bytes), use a dynamic allocation if
needed (tc qdisc add dev eth0 ingress ...)

dev_ingress_queue(dev) helper should be used only with RTNL taken.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 9 insertions, 1 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index ceed3474014a..92d81edd5808 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -986,7 +986,7 @@ struct net_device {
         rx_handler_func_t       *rx_handler;
         void                    *rx_handler_data;
 
-        struct netdev_queue     ingress_queue; /* use two cache lines */
+        struct netdev_queue __rcu *ingress_queue;
 
 /*
  * Cache lines mostly used on transmit path
diff --git a/include/linux/rtnetlink.h b/include/linux/rtnetlink.h
index 68c436bddc88..0bb7b48632bd 100644
--- a/include/linux/rtnetlink.h
+++ b/include/linux/rtnetlink.h
@@ -6,6 +6,7 @@
 #include <linux/if_link.h>
 #include <linux/if_addr.h>
 #include <linux/neighbour.h>
+#include <linux/netdevice.h>
 
 /* rtnetlink families. Values up to 127 are reserved for real address
  * families, values above 128 may be used arbitrarily.
@@ -769,6 +770,13 @@ extern int lockdep_rtnl_is_held(void);
 #define rtnl_dereference(p)                                     \
         rcu_dereference_check(p, lockdep_rtnl_is_held())
 
+static inline struct netdev_queue *dev_ingress_queue(struct net_device *dev)
+{
+        return rtnl_dereference(dev->ingress_queue);
+}
+
+extern struct netdev_queue *dev_ingress_queue_create(struct net_device *dev);
+
 extern void rtnetlink_init(void);
 extern void __rtnl_unlock(void);