net: dsa: create a dsa_lag structure

The main purpose of this change is to create a data structure for a LAG
as seen by DSA. This is similar to what we have for bridging - we pass a
copy of this structure by value to ->port_lag_join and ->port_lag_leave.
For now we keep the lag_dev, id and a reference count in it. Future
patches will add a list of FDB entries for the LAG (these also need to
be refcounted to work properly).

The LAG structure is created using dsa_port_lag_create() and destroyed
using dsa_port_lag_destroy(), just like we have for bridging.

Because now, the dsa_lag itself is refcounted, we can simplify
dsa_lag_map() and dsa_lag_unmap(). These functions need to keep a LAG in
the dst->lags array only as long as at least one port uses it. The
refcounting logic inside those functions can be removed now - they are
called only when we should perform the operation.

dsa_lag_dev() is renamed to dsa_lag_by_id() and now returns the dsa_lag
structure instead of the lag_dev net_device.

dsa_lag_foreach_port() now takes the dsa_lag structure as argument.

dst->lags holds an array of dsa_lag structures.

dsa_lag_map() now also saves the dsa_lag->id value, so that linear
walking of dst->lags in drivers using dsa_lag_id() is no longer
necessary. They can just look at lag.id.

dsa_port_lag_id_get() is a helper, similar to dsa_port_bridge_num_get(),
which can be used by drivers to get the LAG ID assigned by DSA to a
given port.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 37 insertions, 13 deletions

diff --git a/include/net/dsa.h b/include/net/dsa.h
index 3ae93adda25d..81ed34998416 100644
--- a/include/net/dsa.h
+++ b/include/net/dsa.h
@@ -116,6 +116,12 @@ struct dsa_netdevice_ops {
 #define MODULE_ALIAS_DSA_TAG_DRIVER(__proto)				\
 	MODULE_ALIAS(DSA_TAG_DRIVER_ALIAS __stringify(__proto##_VALUE))
 
+struct dsa_lag {
+	struct net_device *dev;
+	unsigned int id;
+	refcount_t refcount;
+};
+
 struct dsa_switch_tree {
 	struct list_head	list;
 
@@ -134,7 +140,7 @@ struct dsa_switch_tree {
 	/* Maps offloaded LAG netdevs to a zero-based linear ID for
 	 * drivers that need it.
 	 */
-	struct net_device **lags;
+	struct dsa_lag **lags;
 
 	/* Tagging protocol operations */
 	const struct dsa_device_ops *tag_ops;
@@ -170,14 +176,14 @@ struct dsa_switch_tree {
 
 #define dsa_lag_foreach_port(_dp, _dst, _lag)			\
 	list_for_each_entry((_dp), &(_dst)->ports, list)	\
-		if ((_dp)->lag_dev == (_lag))
+		if (dsa_port_offloads_lag((_dp), (_lag)))
 
 #define dsa_hsr_foreach_port(_dp, _ds, _hsr)			\
 	list_for_each_entry((_dp), &(_ds)->dst->ports, list)	\
 		if ((_dp)->ds == (_ds) && (_dp)->hsr_dev == (_hsr))
 
-static inline struct net_device *dsa_lag_dev(struct dsa_switch_tree *dst,
-					     unsigned int id)
+static inline struct dsa_lag *dsa_lag_by_id(struct dsa_switch_tree *dst,
+					    unsigned int id)
 {
 	/* DSA LAG IDs are one-based, dst->lags is zero-based */
 	return dst->lags[id - 1];
@@ -189,8 +195,10 @@ static inline int dsa_lag_id(struct dsa_switch_tree *dst,
 	unsigned int id;
 
 	dsa_lags_foreach_id(id, dst) {
-		if (dsa_lag_dev(dst, id) == lag_dev)
-			return id;
+		struct dsa_lag *lag = dsa_lag_by_id(dst, id);
+
+		if (lag->dev == lag_dev)
+			return lag->id;
 	}
 
 	return -ENODEV;
@@ -293,7 +301,7 @@ struct dsa_port {
 	struct devlink_port	devlink_port;
 	struct phylink		*pl;
 	struct phylink_config	pl_config;
-	struct net_device	*lag_dev;
+	struct dsa_lag		*lag;
 	struct net_device	*hsr_dev;
 
 	struct list_head list;
@@ -643,14 +651,30 @@ static inline bool dsa_port_is_vlan_filtering(const struct dsa_port *dp)
 		return dp->vlan_filtering;
 }
 
+static inline unsigned int dsa_port_lag_id_get(struct dsa_port *dp)
+{
+	return dp->lag ? dp->lag->id : 0;
+}
+
+static inline struct net_device *dsa_port_lag_dev_get(struct dsa_port *dp)
+{
+	return dp->lag ? dp->lag->dev : NULL;
+}
+
+static inline bool dsa_port_offloads_lag(struct dsa_port *dp,
+					 const struct dsa_lag *lag)
+{
+	return dsa_port_lag_dev_get(dp) == lag->dev;
+}
+
 static inline
 struct net_device *dsa_port_to_bridge_port(const struct dsa_port *dp)
 {
 	if (!dp->bridge)
 		return NULL;
 
-	if (dp->lag_dev)
-		return dp->lag_dev;
+	if (dp->lag)
+		return dp->lag->dev;
 	else if (dp->hsr_dev)
 		return dp->hsr_dev;
 
@@ -968,10 +992,10 @@ struct dsa_switch_ops {
 	int	(*crosschip_lag_change)(struct dsa_switch *ds, int sw_index,
 					int port);
 	int	(*crosschip_lag_join)(struct dsa_switch *ds, int sw_index,
-				      int port, struct net_device *lag_dev,
+				      int port, struct dsa_lag lag,
 				      struct netdev_lag_upper_info *info);
 	int	(*crosschip_lag_leave)(struct dsa_switch *ds, int sw_index,
-				       int port, struct net_device *lag_dev);
+				       int port, struct dsa_lag lag);
 
 	/*
 	 * PTP functionality
@@ -1043,10 +1067,10 @@ struct dsa_switch_ops {
 	 */
 	int	(*port_lag_change)(struct dsa_switch *ds, int port);
 	int	(*port_lag_join)(struct dsa_switch *ds, int port,
-				 struct net_device *lag_dev,
+				 struct dsa_lag lag,
 				 struct netdev_lag_upper_info *info);
 	int	(*port_lag_leave)(struct dsa_switch *ds, int port,
-				  struct net_device *lag_dev);
+				  struct dsa_lag lag);
 
 	/*
 	 * HSR integration