1 files changed, 48 insertions, 0 deletions

diff --git a/net/dsa/dsa2.c b/net/dsa/dsa2.c
index dcd67801eca4..1b2b25d7bd02 100644
--- a/net/dsa/dsa2.c
+++ b/net/dsa/dsa2.c
@@ -21,6 +21,9 @@
 static DEFINE_MUTEX(dsa2_mutex);
 LIST_HEAD(dsa_tree_list);
 
+/* Track the bridges with forwarding offload enabled */
+static unsigned long dsa_fwd_offloading_bridges;
+
 /**
  * dsa_tree_notify - Execute code for all switches in a DSA switch tree.
  * @dst: collection of struct dsa_switch devices to notify.
@@ -126,6 +129,51 @@ void dsa_lag_unmap(struct dsa_switch_tree *dst, struct net_device *lag)
 	}
 }
 
+static int dsa_bridge_num_find(const struct net_device *bridge_dev)
+{
+	struct dsa_switch_tree *dst;
+	struct dsa_port *dp;
+
+	/* When preparing the offload for a port, it will have a valid
+	 * dp->bridge_dev pointer but a not yet valid dp->bridge_num.
+	 * However there might be other ports having the same dp->bridge_dev
+	 * and a valid dp->bridge_num, so just ignore this port.
+	 */
+	list_for_each_entry(dst, &dsa_tree_list, list)
+		list_for_each_entry(dp, &dst->ports, list)
+			if (dp->bridge_dev == bridge_dev &&
+			    dp->bridge_num != -1)
+				return dp->bridge_num;
+
+	return -1;
+}
+
+int dsa_bridge_num_get(const struct net_device *bridge_dev, int max)
+{
+	int bridge_num = dsa_bridge_num_find(bridge_dev);
+
+	if (bridge_num < 0) {
+		/* First port that offloads TX forwarding for this bridge */
+		bridge_num = find_first_zero_bit(&dsa_fwd_offloading_bridges,
+						 DSA_MAX_NUM_OFFLOADING_BRIDGES);
+		if (bridge_num >= max)
+			return -1;
+
+		set_bit(bridge_num, &dsa_fwd_offloading_bridges);
+	}
+
+	return bridge_num;
+}
+
+void dsa_bridge_num_put(const struct net_device *bridge_dev, int bridge_num)
+{
+	/* Check if the bridge is still in use, otherwise it is time
+	 * to clean it up so we can reuse this bridge_num later.
+	 */
+	if (!dsa_bridge_num_find(bridge_dev))
+		clear_bit(bridge_num, &dsa_fwd_offloading_bridges);
+}
+
 struct dsa_switch *dsa_switch_find(int tree_index, int sw_index)
 {
 	struct dsa_switch_tree *dst;