switchdev: Add SWITCHDEV_PORT_ATTR_SET

In preparation for allowing switchdev enabled drivers to veto specific
attribute settings from within the context of the caller, introduce a
new switchdev notifier type for port attributes.
Suggested-by: NIdo Schimmel <idosch@mellanox.com>
Reviewed-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

include/net/switchdev.h

@@ -132,6 +132,7 @@ enum switchdev_notifier_type {
 
 	SWITCHDEV_PORT_OBJ_ADD, /* Blocking. */
 	SWITCHDEV_PORT_OBJ_DEL, /* Blocking. */
+	SWITCHDEV_PORT_ATTR_SET, /* May be blocking . */
 
 	SWITCHDEV_VXLAN_FDB_ADD_TO_BRIDGE,
 	SWITCHDEV_VXLAN_FDB_DEL_TO_BRIDGE,
@@ -160,6 +161,13 @@ struct switchdev_notifier_port_obj_info {
 	bool handled;
 };
 
+struct switchdev_notifier_port_attr_info {
+	struct switchdev_notifier_info info; /* must be first */
+	const struct switchdev_attr *attr;
+	struct switchdev_trans *trans;
+	bool handled;
+};
+
 static inline struct net_device *
 switchdev_notifier_info_to_dev(const struct switchdev_notifier_info *info)
 {
@@ -212,7 +220,15 @@ int switchdev_handle_port_obj_del(struct net_device *dev,
 			int (*del_cb)(struct net_device *dev,
 				      const struct switchdev_obj *obj));
 
+int switchdev_handle_port_attr_set(struct net_device *dev,
+			struct switchdev_notifier_port_attr_info *port_attr_info,
+			bool (*check_cb)(const struct net_device *dev),
+			int (*set_cb)(struct net_device *dev,
+				      const struct switchdev_attr *attr,
+				      struct switchdev_trans *trans));
+
 #define SWITCHDEV_SET_OPS(netdev, ops) ((netdev)->switchdev_ops = (ops))
+
 #else
 
 static inline void switchdev_deferred_process(void)
@@ -299,6 +315,17 @@ switchdev_handle_port_obj_del(struct net_device *dev,
 	return 0;
 }
 
+static inline int
+switchdev_handle_port_attr_set(struct net_device *dev,
+			struct switchdev_notifier_port_attr_info *port_attr_info,
+			bool (*check_cb)(const struct net_device *dev),
+			int (*set_cb)(struct net_device *dev,
+				      const struct switchdev_attr *attr,
+				      struct switchdev_trans *trans))
+{
+	return 0;
+}
+
 #define SWITCHDEV_SET_OPS(netdev, ops) do {} while (0)
 
 #endif

net/switchdev/switchdev.c

@@ -655,3 +655,54 @@ int switchdev_handle_port_obj_del(struct net_device *dev,
 	return err;
 }
 EXPORT_SYMBOL_GPL(switchdev_handle_port_obj_del);
+
+static int __switchdev_handle_port_attr_set(struct net_device *dev,
+			struct switchdev_notifier_port_attr_info *port_attr_info,
+			bool (*check_cb)(const struct net_device *dev),
+			int (*set_cb)(struct net_device *dev,
+				      const struct switchdev_attr *attr,
+				      struct switchdev_trans *trans))
+{
+	struct net_device *lower_dev;
+	struct list_head *iter;
+	int err = -EOPNOTSUPP;
+
+	if (check_cb(dev)) {
+		port_attr_info->handled = true;
+		return set_cb(dev, port_attr_info->attr,
+			      port_attr_info->trans);
+	}
+
+	/* Switch ports might be stacked under e.g. a LAG. Ignore the
+	 * unsupported devices, another driver might be able to handle them. But
+	 * propagate to the callers any hard errors.
+	 *
+	 * If the driver does its own bookkeeping of stacked ports, it's not
+	 * necessary to go through this helper.
+	 */
+	netdev_for_each_lower_dev(dev, lower_dev, iter) {
+		err = __switchdev_handle_port_attr_set(lower_dev, port_attr_info,
+						       check_cb, set_cb);
+		if (err && err != -EOPNOTSUPP)
+			return err;
+	}
+
+	return err;
+}
+
+int switchdev_handle_port_attr_set(struct net_device *dev,
+			struct switchdev_notifier_port_attr_info *port_attr_info,
+			bool (*check_cb)(const struct net_device *dev),
+			int (*set_cb)(struct net_device *dev,
+				      const struct switchdev_attr *attr,
+				      struct switchdev_trans *trans))
+{
+	int err;
+
+	err = __switchdev_handle_port_attr_set(dev, port_attr_info, check_cb,
+					       set_cb);
+	if (err == -EOPNOTSUPP)
+		err = 0;
+	return err;
+}
+EXPORT_SYMBOL_GPL(switchdev_handle_port_attr_set);