[RFC PATCH 2/4] net: Add lower dev list helpers
From: John Fastabend <john.fastabend@gmail.com>
Date: 2013-09-11 18:47:12
Subsystem:
networking drivers, networking [general], the rest · Maintainers:
Andrew Lunn, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
This patch adds helpers to traverse the lower dev lists, these helpers match the upper dev list implementation. VSI implementers may use these to track a list of connected netdevs. This is easier then having drivers do their own accounting. Signed-off-by: John Fastabend <redacted> --- include/linux/netdevice.h | 8 ++++++++ net/core/dev.c | 25 +++++++++++++++++++++++++ 2 files changed, 33 insertions(+)
diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 041b42a..4d24b38 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h@@ -2813,6 +2813,8 @@ extern int bpf_jit_enable; extern bool netdev_has_upper_dev(struct net_device *dev, struct net_device *upper_dev); extern bool netdev_has_any_upper_dev(struct net_device *dev); +extern struct net_device *netdev_lower_get_next_dev_rcu(struct net_device *dev, + struct list_head **iter); extern struct net_device *netdev_upper_get_next_dev_rcu(struct net_device *dev, struct list_head **iter);
@@ -2823,6 +2825,12 @@ extern struct net_device *netdev_upper_get_next_dev_rcu(struct net_device *dev, upper; \ upper = netdev_upper_get_next_dev_rcu(dev, &(iter))) +#define netdev_for_each_lower_dev_rcu(dev, lower, iter) \ + for (iter = &(dev)->lower_dev_list, \ + lower = netdev_lower_get_next_dev_rcu(dev, &(iter)); \ + lower; \ + lower = netdev_lower_get_next_dev_rcu(dev, &(iter))) + extern struct net_device *netdev_master_upper_dev_get(struct net_device *dev); extern struct net_device *netdev_master_upper_dev_get_rcu(struct net_device *dev); extern int netdev_upper_dev_link(struct net_device *dev,
diff --git a/net/core/dev.c b/net/core/dev.c
index 5c713f2..65ed610 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -4468,6 +4468,31 @@ struct net_device *netdev_master_upper_dev_get(struct net_device *dev) } EXPORT_SYMBOL(netdev_master_upper_dev_get); +/* netdev_lower_get_next_dev_rcu - Get the next dev from lower list + * @dev: device + * @iter: list_head ** of the current position + * + * Gets the next device from the dev's lower list, starting from iter + * position. The caller must hold RTNL/RCU read lock. + */ +struct net_device *netdev_lower_get_next_dev_rcu(struct net_device *dev, + struct list_head **iter) +{ + struct netdev_adjacent *lower; + + WARN_ON_ONCE(!rcu_read_lock_held()); + + lower = list_entry_rcu((*iter)->next, struct netdev_adjacent, list); + + if (&lower->list == &dev->lower_dev_list) + return NULL; + + *iter = &lower->list; + + return lower->dev; +} +EXPORT_SYMBOL(netdev_lower_get_next_dev_rcu); + /* netdev_upper_get_next_dev_rcu - Get the next dev from upper list * @dev: device * @iter: list_head ** of the current position