[PATCH 3.13 017/212] net: Find the nesting level of a given device by type.

Kamal Mostafa
2014-06-17T21:41:51Z

From: Vlad Yasevich <vyasevic@redhat.com>

[ Upstream commit 4085ebe8c31face855fd01ee40372cb4aab1df3a ]

Multiple devices in the kernel can be stacked/nested and they
need to know their nesting level for the purposes of lockdep.
This patch provides a generic function that determines a nesting
level of a particular device by its type (ex: vlan, macvlan, etc).
We only care about nesting of the same type of devices.

For example:
eth0 <- vlan0.10 <- macvlan0 <- vlan1.20

The nesting level of vlan1.20 would be 1, since there is another vlan
in the stack under it.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
---
include/linux/netdevice.h | 10 ++++++++++
net/core/dev.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 60 insertions(+)

diff --git a/include/linux/netdevice.h b/include/linux/netdevice.h
index 2177a6b..d7df837 100644
--- a/include/linux/netdevice.h
+++ b/include/linux/netdevice.h
@@ -2881,6 +2881,14 @@ void *netdev_lower_get_next_private_rcu(struct net_device *dev,
priv; \
priv = netdev_lower_get_next_private_rcu(dev, &(iter)))

+void *netdev_lower_get_next(struct net_device *dev,
+ struct list_head **iter);
+#define netdev_for_each_lower_dev(dev, ldev, iter) \
+ for (iter = &(dev)->adj_list.lower, \
+ ldev = netdev_lower_get_next(dev, &(iter)); \
+ ldev; \
+ ldev = netdev_lower_get_next(dev, &(iter)))
+
void *netdev_adjacent_get_private(struct list_head *adj_list);
struct net_device *netdev_master_upper_dev_get(struct net_device *dev);
struct net_device *netdev_master_upper_dev_get_rcu(struct net_device *dev);
@@ -2896,6 +2904,8 @@ void *netdev_lower_dev_get_private_rcu(struct net_device *dev,
struct net_device *lower_dev);
void *netdev_lower_dev_get_private(struct net_device *dev,
struct net_device *lower_dev);
+int dev_get_nest_level(struct net_device *dev,
+ bool (*type_check)(struct net_device *dev));
int skb_checksum_help(struct sk_buff *skb);
struct sk_buff *__skb_gso_segment(struct sk_buff *skb,
netdev_features_t features, bool tx_path);
diff --git a/net/core/dev.c b/net/core/dev.c
index 72fb1fe..ff0c02e 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -4578,6 +4578,32 @@ void *netdev_lower_get_next_private_rcu(struct net_device *dev,
EXPORT_SYMBOL(netdev_lower_get_next_private_rcu);

/**
+ * netdev_lower_get_next - Get the next device from the lower neighbour
+ * list
+ * @dev: device
+ * @iter: list_head ** of the current position
+ *
+ * Gets the next netdev_adjacent from the dev's lower neighbour
+ * list, starting from iter position. The caller must hold RTNL lock or
+ * its own locking that guarantees that the neighbour lower
+ * list will remain unchainged.
+ */
+void *netdev_lower_get_next(struct net_device *dev, struct list_head **iter)
+{
+ struct netdev_adjacent *lower;
+
+ lower = list_entry((*iter)->next, struct netdev_adjacent, list);
+
+ if (&lower->list == &dev->adj_list.lower)
+ return NULL;
+
+ *iter = &lower->list;
+
+ return lower->dev;
+}
+EXPORT_SYMBOL(netdev_lower_get_next);
+
+/**
* netdev_master_upper_dev_get_rcu - Get master upper device
* @dev: device
*
@@ -4999,6 +5025,30 @@ void *netdev_lower_dev_get_private(struct net_device *dev,
}
EXPORT_SYMBOL(netdev_lower_dev_get_private);

+
+int dev_get_nest_level(struct net_device *dev,
+ bool (*type_check)(struct net_device *dev))
+{
+ struct net_device *lower = NULL;
+ struct list_head *iter;
+ int max_nest = -1;
+ int nest;
+
+ ASSERT_RTNL();
+
+ netdev_for_each_lower_dev(dev, lower, iter) {
+ nest = dev_get_nest_level(lower, type_check);
+ if (max_nest < nest)
+ max_nest = nest;
+ }
+
+ if (type_check(dev))
+ max_nest++;
+
+ return max_nest;
+}
+EXPORT_SYMBOL(dev_get_nest_level);
+
static void dev_change_rx_flags(struct net_device *dev, int flags)
{
const struct net_device_ops *ops = dev->netdev_ops;
--
1.9.1