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Commit 1a3f060c authored by David Ahern's avatar David Ahern Committed by David S. Miller
Browse files

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: default avatarDavid Ahern <dsa@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 790510d9

include/linux/netdevice.h

+17 −0
Original line number Diff line number Diff line
@@ -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);

net/core/dev.c

+155 −0
Original line number Diff line number Diff line
@@ -5155,6 +5155,31 @@ bool netdev_has_upper_dev(struct net_device *dev, 
}

EXPORT_SYMBOL(netdev_has_upper_dev);



/**

 * netdev_has_upper_dev_all - Check if device is linked to an upper device

 * @dev: device

 * @upper_dev: upper device to check

 *

 * Find out if a device is linked to specified upper device and return true

 * in case it is. Note that this checks the entire upper device chain.

 * The caller must hold rcu lock.

 */



static int __netdev_has_upper_dev(struct net_device *upper_dev, void *data)

{

	struct net_device *dev = data;



	return upper_dev == dev;

}



bool netdev_has_upper_dev_all_rcu(struct net_device *dev,

				  struct net_device *upper_dev)

{

	return !!netdev_walk_all_upper_dev_rcu(dev, __netdev_has_upper_dev,

					       upper_dev);

}

EXPORT_SYMBOL(netdev_has_upper_dev_all_rcu);



/**

 * netdev_has_any_upper_dev - Check if device is linked to some device

 * @dev: device
@@ -5255,6 +5280,51 @@ struct net_device *netdev_all_upper_get_next_dev_rcu(struct net_device *dev, 
}

EXPORT_SYMBOL(netdev_all_upper_get_next_dev_rcu);



static struct net_device *netdev_next_upper_dev_rcu(struct net_device *dev,

						    struct list_head **iter)

{

	struct netdev_adjacent *upper;



	WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_rtnl_is_held());



	upper = list_entry_rcu((*iter)->next, struct netdev_adjacent, list);



	if (&upper->list == &dev->adj_list.upper)

		return NULL;



	*iter = &upper->list;



	return upper->dev;

}



int netdev_walk_all_upper_dev_rcu(struct net_device *dev,

				  int (*fn)(struct net_device *dev,

					    void *data),

				  void *data)

{

	struct net_device *udev;

	struct list_head *iter;

	int ret;



	for (iter = &dev->adj_list.upper,

	     udev = netdev_next_upper_dev_rcu(dev, &iter);

	     udev;

	     udev = netdev_next_upper_dev_rcu(dev, &iter)) {

		/* first is the upper device itself */

		ret = fn(udev, data);

		if (ret)

			return ret;



		/* then look at all of its upper devices */

		ret = netdev_walk_all_upper_dev_rcu(udev, fn, data);

		if (ret)

			return ret;

	}



	return 0;

}

EXPORT_SYMBOL_GPL(netdev_walk_all_upper_dev_rcu);



/**

 * netdev_lower_get_next_private - Get the next ->private from the

 *				   lower neighbour list
@@ -5361,6 +5431,49 @@ struct net_device *netdev_all_lower_get_next(struct net_device *dev, struct list 
}

EXPORT_SYMBOL(netdev_all_lower_get_next);



static struct net_device *netdev_next_lower_dev(struct net_device *dev,

						struct list_head **iter)

{

	struct netdev_adjacent *lower;



	lower = list_entry(*iter, struct netdev_adjacent, list);



	if (&lower->list == &dev->adj_list.lower)

		return NULL;



	*iter = lower->list.next;



	return lower->dev;

}



int netdev_walk_all_lower_dev(struct net_device *dev,

			      int (*fn)(struct net_device *dev,

					void *data),

			      void *data)

{

	struct net_device *ldev;

	struct list_head *iter;

	int ret;



	for (iter = &dev->adj_list.lower,

	     ldev = netdev_next_lower_dev(dev, &iter);

	     ldev;

	     ldev = netdev_next_lower_dev(dev, &iter)) {

		/* first is the lower device itself */

		ret = fn(ldev, data);

		if (ret)

			return ret;



		/* then look at all of its lower devices */

		ret = netdev_walk_all_lower_dev(ldev, fn, data);

		if (ret)

			return ret;

	}



	return 0;

}

EXPORT_SYMBOL_GPL(netdev_walk_all_lower_dev);



/**

 * netdev_all_lower_get_next_rcu - Get the next device from all

 *				   lower neighbour list, RCU variant
@@ -5382,6 +5495,48 @@ struct net_device *netdev_all_lower_get_next_rcu(struct net_device *dev, 
}

EXPORT_SYMBOL(netdev_all_lower_get_next_rcu);



static struct net_device *netdev_next_lower_dev_rcu(struct net_device *dev,

						    struct list_head **iter)

{

	struct netdev_adjacent *lower;



	lower = list_entry_rcu((*iter)->next, struct netdev_adjacent, list);

	if (&lower->list == &dev->adj_list.lower)

		return NULL;



	*iter = &lower->list;



	return lower->dev;

}



int netdev_walk_all_lower_dev_rcu(struct net_device *dev,

				  int (*fn)(struct net_device *dev,

					    void *data),

				  void *data)

{

	struct net_device *ldev;

	struct list_head *iter;

	int ret;



	for (iter = &dev->adj_list.lower,

	     ldev = netdev_next_lower_dev_rcu(dev, &iter);

	     ldev;

	     ldev = netdev_next_lower_dev_rcu(dev, &iter)) {

		/* first is the lower device itself */

		ret = fn(ldev, data);

		if (ret)

			return ret;



		/* then look at all of its lower devices */

		ret = netdev_walk_all_lower_dev_rcu(ldev, fn, data);

		if (ret)

			return ret;

	}



	return 0;

}

EXPORT_SYMBOL_GPL(netdev_walk_all_lower_dev_rcu);



/**

 * netdev_lower_get_first_private_rcu - Get the first ->private from the

 *				       lower neighbour list, RCU