net: Introduce new api for walking upper and lower devices

This patch introduces netdev_walk_all_upper_dev_rcu,
netdev_walk_all_lower_dev and netdev_walk_all_lower_dev_rcu. These
functions recursively walk the adj_list of devices to determine all upper
and lower devices.

The functions take a callback function that is invoked for each device
in the list. If the callback returns non-0, the walk is terminated and
the functions return that code back to callers.

v3
- simplified netdev_has_upper_dev_all_rcu and __netdev_has_upper_dev and
  removed typecast as suggested by Stephen

v2
- fixed definition of netdev_next_lower_dev_rcu to mirror the upper_dev
  version.

Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 17 insertions, 0 deletions

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index bf341b6..a5902d99 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -3778,6 +3778,14 @@ struct net_device *netdev_all_upper_get_next_dev_rcu(struct net_device *dev,
 	     updev; \
 	     updev = netdev_all_upper_get_next_dev_rcu(dev, &(iter)))
 
+int netdev_walk_all_upper_dev_rcu(struct net_device *dev,
+				  int (*fn)(struct net_device *upper_dev,
+					    void *data),
+				  void *data);
+
+bool netdev_has_upper_dev_all_rcu(struct net_device *dev,
+				  struct net_device *upper_dev);
+
 void *netdev_lower_get_next_private(struct net_device *dev,
 				    struct list_head **iter);
 void *netdev_lower_get_next_private_rcu(struct net_device *dev,
@@ -3821,6 +3829,15 @@ struct net_device *netdev_all_lower_get_next_rcu(struct net_device *dev,
 	     ldev; \
 	     ldev = netdev_all_lower_get_next_rcu(dev, &(iter)))
 
+int netdev_walk_all_lower_dev(struct net_device *dev,
+			      int (*fn)(struct net_device *lower_dev,
+					void *data),
+			      void *data);
+int netdev_walk_all_lower_dev_rcu(struct net_device *dev,
+				  int (*fn)(struct net_device *lower_dev,
+					    void *data),
+				  void *data);
+
 void *netdev_adjacent_get_private(struct list_head *adj_list);
 void *netdev_lower_get_first_private_rcu(struct net_device *dev);
 struct net_device *netdev_master_upper_dev_get(struct net_device *dev);