net: create device lookup API with reference tracking

New users of dev_get_by_index() and dev_get_by_name() keep
getting added and it would be nice to steer them towards
the APIs with reference tracking.

Add variants of those calls which allocate the reference
tracker and use them in a couple of places.

Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 45 insertions, 18 deletions

diff --git a/net/core/dev.c b/net/core/dev.c
index c2456b3667fe5..63abb0463c245 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -758,29 +758,43 @@ struct net_device *dev_get_by_name_rcu(struct net *net, const char *name)
 }
 EXPORT_SYMBOL(dev_get_by_name_rcu);
 
+/* Deprecated for new users, call netdev_get_by_name() instead */
+struct net_device *dev_get_by_name(struct net *net, const char *name)
+{
+	struct net_device *dev;
+
+	rcu_read_lock();
+	dev = dev_get_by_name_rcu(net, name);
+	dev_hold(dev);
+	rcu_read_unlock();
+	return dev;
+}
+EXPORT_SYMBOL(dev_get_by_name);
+
 /**
- *	dev_get_by_name		- find a device by its name
+ *	netdev_get_by_name() - find a device by its name
  *	@net: the applicable net namespace
  *	@name: name to find
+ *	@tracker: tracking object for the acquired reference
+ *	@gfp: allocation flags for the tracker
  *
  *	Find an interface by name. This can be called from any
  *	context and does its own locking. The returned handle has
- *	the usage count incremented and the caller must use dev_put() to
+ *	the usage count incremented and the caller must use netdev_put() to
  *	release it when it is no longer needed. %NULL is returned if no
  *	matching device is found.
  */
-
-struct net_device *dev_get_by_name(struct net *net, const char *name)
+struct net_device *netdev_get_by_name(struct net *net, const char *name,
+				      netdevice_tracker *tracker, gfp_t gfp)
 {
 	struct net_device *dev;
 
-	rcu_read_lock();
-	dev = dev_get_by_name_rcu(net, name);
-	dev_hold(dev);
-	rcu_read_unlock();
+	dev = dev_get_by_name(net, name);
+	if (dev)
+		netdev_tracker_alloc(dev, tracker, gfp);
 	return dev;
 }
-EXPORT_SYMBOL(dev_get_by_name);
+EXPORT_SYMBOL(netdev_get_by_name);
 
 /**
  *	__dev_get_by_index - find a device by its ifindex
@@ -831,29 +845,42 @@ struct net_device *dev_get_by_index_rcu(struct net *net, int ifindex)
 }
 EXPORT_SYMBOL(dev_get_by_index_rcu);
 
+/* Deprecated for new users, call netdev_get_by_index() instead */
+struct net_device *dev_get_by_index(struct net *net, int ifindex)
+{
+	struct net_device *dev;
+
+	rcu_read_lock();
+	dev = dev_get_by_index_rcu(net, ifindex);
+	dev_hold(dev);
+	rcu_read_unlock();
+	return dev;
+}
+EXPORT_SYMBOL(dev_get_by_index);
 
 /**
- *	dev_get_by_index - find a device by its ifindex
+ *	netdev_get_by_index() - find a device by its ifindex
  *	@net: the applicable net namespace
  *	@ifindex: index of device
+ *	@tracker: tracking object for the acquired reference
+ *	@gfp: allocation flags for the tracker
  *
  *	Search for an interface by index. Returns NULL if the device
  *	is not found or a pointer to the device. The device returned has
  *	had a reference added and the pointer is safe until the user calls
- *	dev_put to indicate they have finished with it.
+ *	netdev_put() to indicate they have finished with it.
  */
-
-struct net_device *dev_get_by_index(struct net *net, int ifindex)
+struct net_device *netdev_get_by_index(struct net *net, int ifindex,
+				       netdevice_tracker *tracker, gfp_t gfp)
 {
 	struct net_device *dev;
 
-	rcu_read_lock();
-	dev = dev_get_by_index_rcu(net, ifindex);
-	dev_hold(dev);
-	rcu_read_unlock();
+	dev = dev_get_by_index(net, ifindex);
+	if (dev)
+		netdev_tracker_alloc(dev, tracker, gfp);
 	return dev;
 }
-EXPORT_SYMBOL(dev_get_by_index);
+EXPORT_SYMBOL(netdev_get_by_index);
 
 /**
  *	dev_get_by_napi_id - find a device by napi_id