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, 16 insertions, 21 deletions

diff --git a/drivers/net/dsa/qca8k.c b/drivers/net/dsa/qca8k.c
index ed55e9357c2b..6844106975a9 100644
--- a/drivers/net/dsa/qca8k.c
+++ b/drivers/net/dsa/qca8k.c
@@ -2646,18 +2646,16 @@ qca8k_get_tag_protocol(struct dsa_switch *ds, int port,
 }
 
 static bool
-qca8k_lag_can_offload(struct dsa_switch *ds,
-		      struct net_device *lag_dev,
+qca8k_lag_can_offload(struct dsa_switch *ds, struct dsa_lag lag,
 		      struct netdev_lag_upper_info *info)
 {
 	struct dsa_port *dp;
-	int id, members = 0;
+	int members = 0;
 
-	id = dsa_lag_id(ds->dst, lag_dev);
-	if (id <= 0 || id > ds->num_lag_ids)
+	if (!lag.id)
 		return false;
 
-	dsa_lag_foreach_port(dp, ds->dst, lag_dev)
+	dsa_lag_foreach_port(dp, ds->dst, &lag)
 		/* Includes the port joining the LAG */
 		members++;
 
@@ -2675,16 +2673,14 @@ qca8k_lag_can_offload(struct dsa_switch *ds,
 }
 
 static int
-qca8k_lag_setup_hash(struct dsa_switch *ds,
-		     struct net_device *lag_dev,
+qca8k_lag_setup_hash(struct dsa_switch *ds, struct dsa_lag lag,
 		     struct netdev_lag_upper_info *info)
 {
+	struct net_device *lag_dev = lag.dev;
 	struct qca8k_priv *priv = ds->priv;
 	bool unique_lag = true;
+	unsigned int i;
 	u32 hash = 0;
-	int i, id;
-
-	id = dsa_lag_id(ds->dst, lag_dev);
 
 	switch (info->hash_type) {
 	case NETDEV_LAG_HASH_L23:
@@ -2701,7 +2697,7 @@ qca8k_lag_setup_hash(struct dsa_switch *ds,
 
 	/* Check if we are the unique configured LAG */
 	dsa_lags_foreach_id(i, ds->dst)
-		if (i != id && dsa_lag_dev(ds->dst, i)) {
+		if (i != lag.id && dsa_lag_by_id(ds->dst, i)) {
 			unique_lag = false;
 			break;
 		}
@@ -2726,14 +2722,14 @@ qca8k_lag_setup_hash(struct dsa_switch *ds,
 
 static int
 qca8k_lag_refresh_portmap(struct dsa_switch *ds, int port,
-			  struct net_device *lag_dev, bool delete)
+			  struct dsa_lag lag, bool delete)
 {
 	struct qca8k_priv *priv = ds->priv;
 	int ret, id, i;
 	u32 val;
 
 	/* DSA LAG IDs are one-based, hardware is zero-based */
-	id = dsa_lag_id(ds->dst, lag_dev) - 1;
+	id = lag.id - 1;
 
 	/* Read current port member */
 	ret = regmap_read(priv->regmap, QCA8K_REG_GOL_TRUNK_CTRL0, &val);
@@ -2795,27 +2791,26 @@ qca8k_lag_refresh_portmap(struct dsa_switch *ds, int port,
 }
 
 static int
-qca8k_port_lag_join(struct dsa_switch *ds, int port,
-		    struct net_device *lag_dev,
+qca8k_port_lag_join(struct dsa_switch *ds, int port, struct dsa_lag lag,
 		    struct netdev_lag_upper_info *info)
 {
 	int ret;
 
-	if (!qca8k_lag_can_offload(ds, lag_dev, info))
+	if (!qca8k_lag_can_offload(ds, lag, info))
 		return -EOPNOTSUPP;
 
-	ret = qca8k_lag_setup_hash(ds, lag_dev, info);
+	ret = qca8k_lag_setup_hash(ds, lag, info);
 	if (ret)
 		return ret;
 
-	return qca8k_lag_refresh_portmap(ds, port, lag_dev, false);
+	return qca8k_lag_refresh_portmap(ds, port, lag, false);
 }
 
 static int
 qca8k_port_lag_leave(struct dsa_switch *ds, int port,
-		     struct net_device *lag_dev)
+		     struct dsa_lag lag)
 {
-	return qca8k_lag_refresh_portmap(ds, port, lag_dev, true);
+	return qca8k_lag_refresh_portmap(ds, port, lag, true);
 }
 
 static void