net: export netdev_next_lower_dev_rcu()

netdev_next_lower_dev_rcu() will be used to implement a function,
which is to walk all lower interfaces.
There are already functions that they walk their lower interface.
(netdev_walk_all_lower_dev_rcu, netdev_walk_all_lower_dev()).
But, there would be cases that couldn't be covered by given
netdev_walk_all_lower_dev_{rcu}() function.
So, some modules would want to implement own function,
which is to walk all lower interfaces.

In the next patch, netdev_next_lower_dev_rcu() will be used.
In addition, this patch removes two unused prototypes in netdevice.h.

Signed-off-by: Taehee Yoo <ap420073@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Author: TaeheeYoo

include/linux/netdevice.h

@@ -72,6 +72,8 @@ void netdev_set_default_ethtool_ops(struct net_device *dev,
 #define NET_RX_SUCCESS		0	/* keep 'em coming, baby */
 #define NET_RX_DROP		1	/* packet dropped */
 
+#define MAX_NEST_DEV 8
+
 /*
  * Transmit return codes: transmit return codes originate from three different
  * namespaces:
@@ -4389,11 +4391,8 @@ void *netdev_lower_get_next(struct net_device *dev,
 	     ldev; \
 	     ldev = netdev_lower_get_next(dev, &(iter)))
 
-struct net_device *netdev_all_lower_get_next(struct net_device *dev,
+struct net_device *netdev_next_lower_dev_rcu(struct net_device *dev,
 					     struct list_head **iter);
-struct net_device *netdev_all_lower_get_next_rcu(struct net_device *dev,
-						 struct list_head **iter);
-
 int netdev_walk_all_lower_dev(struct net_device *dev,
 			      int (*fn)(struct net_device *lower_dev,
 					void *data),

net/core/dev.c

@@ -146,7 +146,6 @@
 #include "net-sysfs.h"
 
 #define MAX_GRO_SKBS 8
-#define MAX_NEST_DEV 8
 
 /* This should be increased if a protocol with a bigger head is added. */
 #define GRO_MAX_HEAD (MAX_HEADER + 128)
@@ -7207,8 +7206,8 @@ static int __netdev_walk_all_lower_dev(struct net_device *dev,
 	return 0;
 }
 
-static struct net_device *netdev_next_lower_dev_rcu(struct net_device *dev,
-						    struct list_head **iter)
+struct net_device *netdev_next_lower_dev_rcu(struct net_device *dev,
+					     struct list_head **iter)
 {
 	struct netdev_adjacent *lower;
 
@@ -7220,6 +7219,7 @@ static struct net_device *netdev_next_lower_dev_rcu(struct net_device *dev,
 
 	return lower->dev;
 }
+EXPORT_SYMBOL(netdev_next_lower_dev_rcu);
 
 static u8 __netdev_upper_depth(struct net_device *dev)
 {