devlink: Introduce rate object

Allow registering rate object for devlink ports with dedicated
devlink_rate_leaf_{create|destroy}() API. Implement new netlink
DEVLINK_CMD_RATE_GET command that is used to retrieve rate object info.
Add new DEVLINK_CMD_RATE_{NEW|DEL} commands that are used for
notifications when creating/deleting leaf rate object.

Rate API is intended to be used for rate limiting of individual
devlink ports (leafs) and their aggregates (nodes).

Example:

$ devlink port show
pci/0000:03:00.0/0
pci/0000:03:00.0/1

$ devlink port function rate show
pci/0000:03:00.0/0: type leaf
pci/0000:03:00.0/1: type leaf

Co-developed-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Vlad Buslov <vladbu@nvidia.com>
Signed-off-by: Dmytro Linkin <dlinkin@nvidia.com>
Reviewed-by: Jiri Pirko <jiri@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/uapi/linux/devlink.h

@@ -126,6 +126,11 @@ enum devlink_command {
 
 	DEVLINK_CMD_HEALTH_REPORTER_TEST,
 
+	DEVLINK_CMD_RATE_GET,		/* can dump */
+	DEVLINK_CMD_RATE_SET,
+	DEVLINK_CMD_RATE_NEW,
+	DEVLINK_CMD_RATE_DEL,
+
 	/* add new commands above here */
 	__DEVLINK_CMD_MAX,
 	DEVLINK_CMD_MAX = __DEVLINK_CMD_MAX - 1
@@ -206,6 +211,10 @@ enum devlink_port_flavour {
 				      */
 };
 
+enum devlink_rate_type {
+	DEVLINK_RATE_TYPE_LEAF,
+};
+
 enum devlink_param_cmode {
 	DEVLINK_PARAM_CMODE_RUNTIME,
 	DEVLINK_PARAM_CMODE_DRIVERINIT,
@@ -534,6 +543,8 @@ enum devlink_attr {
 	DEVLINK_ATTR_RELOAD_ACTION_STATS,       /* nested */
 
 	DEVLINK_ATTR_PORT_PCI_SF_NUMBER,	/* u32 */
+
+	DEVLINK_ATTR_RATE_TYPE,			/* u16 */
 	/* add new attributes above here, update the policy in devlink.c */
 
 	__DEVLINK_ATTR_MAX,