devlink: Allow setting tx rate for devlink rate leaf objects

Implement support for DEVLINK_CMD_RATE_SET command with new attributes
DEVLINK_ATTR_RATE_TX_{SHARE|MAX} that are used to set devlink rate
shared/max tx rate values. Extend devlink ops with new callbacks
rate_leaf_tx_{share|max}_set() to allow supporting drivers to implement
rate control through devlink.

New attributes are optional. Driver implementations are allowed to
support either or both of them.

Shared rate example:

$ devlink port function rate set netdevsim/netdevsim10/0 tx_share 10mbit

$ devlink port function rate show netdevsim/netdevsim10/0
netdevsim/netdevsim10/0: type leaf tx_share 10mbit

Max rate example:

$ devlink port function rate set netdevsim/netdevsim10/0 tx_max 100mbit

$ devlink port function rate show netdevsim/netdevsim10/0
netdevsim/netdevsim10/0: type leaf tx_max 100mbit

Co-developed-by: Vlad Buslov <[email protected]>
Signed-off-by: Vlad Buslov <[email protected]>
Signed-off-by: Dmytro Linkin <[email protected]>
Reviewed-by: Jiri Pirko <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

include/net/devlink.h

@@ -139,6 +139,8 @@ struct devlink_rate {
 	enum devlink_rate_type type;
 	struct devlink *devlink;
 	void *priv;
+	u64 tx_share;
+	u64 tx_max;
 
 	struct devlink_port *devlink_port;
 };
@@ -1465,6 +1467,14 @@ struct devlink_ops {
 				 struct devlink_port *port,
 				 enum devlink_port_fn_state state,
 				 struct netlink_ext_ack *extack);
+
+	/**
+	 * Rate control callbacks.
+	 */
+	int (*rate_leaf_tx_share_set)(struct devlink_rate *devlink_rate, void *priv,
+				      u64 tx_share, struct netlink_ext_ack *extack);
+	int (*rate_leaf_tx_max_set)(struct devlink_rate *devlink_rate, void *priv,
+				    u64 tx_max, struct netlink_ext_ack *extack);
 };
 
 static inline void *devlink_priv(struct devlink *devlink)

include/uapi/linux/devlink.h

@@ -545,6 +545,8 @@ enum devlink_attr {
 	DEVLINK_ATTR_PORT_PCI_SF_NUMBER,	/* u32 */
 
 	DEVLINK_ATTR_RATE_TYPE,			/* u16 */
+	DEVLINK_ATTR_RATE_TX_SHARE,		/* u64 */
+	DEVLINK_ATTR_RATE_TX_MAX,		/* u64 */
 	/* add new attributes above here, update the policy in devlink.c */
 
 	__DEVLINK_ATTR_MAX,

net/core/devlink.c

@@ -803,6 +803,14 @@ static int devlink_nl_rate_fill(struct sk_buff *msg,
 			goto nla_put_failure;
 	}
 
+	if (nla_put_u64_64bit(msg, DEVLINK_ATTR_RATE_TX_SHARE,
+			      devlink_rate->tx_share, DEVLINK_ATTR_PAD))
+		goto nla_put_failure;
+
+	if (nla_put_u64_64bit(msg, DEVLINK_ATTR_RATE_TX_MAX,
+			      devlink_rate->tx_max, DEVLINK_ATTR_PAD))
+		goto nla_put_failure;
+
 	genlmsg_end(msg, hdr);
 	return 0;
 
@@ -1495,6 +1503,76 @@ static int devlink_nl_cmd_port_del_doit(struct sk_buff *skb,
 	return devlink->ops->port_del(devlink, port_index, extack);
 }
 
+static int devlink_nl_rate_set(struct devlink_rate *devlink_rate,
+			       const struct devlink_ops *ops,
+			       struct genl_info *info)
+{
+	struct nlattr **attrs = info->attrs;
+	u64 rate;
+	int err;
+
+	if (attrs[DEVLINK_ATTR_RATE_TX_SHARE]) {
+		rate = nla_get_u64(attrs[DEVLINK_ATTR_RATE_TX_SHARE]);
+		err = ops->rate_leaf_tx_share_set(devlink_rate, devlink_rate->priv,
+						  rate, info->extack);
+		if (err)
+			return err;
+		devlink_rate->tx_share = rate;
+	}
+
+	if (attrs[DEVLINK_ATTR_RATE_TX_MAX]) {
+		rate = nla_get_u64(attrs[DEVLINK_ATTR_RATE_TX_MAX]);
+		err = ops->rate_leaf_tx_max_set(devlink_rate, devlink_rate->priv,
+						rate, info->extack);
+		if (err)
+			return err;
+		devlink_rate->tx_max = rate;
+	}
+
+	return 0;
+}
+
+static bool devlink_rate_set_ops_supported(const struct devlink_ops *ops,
+					   struct genl_info *info,
+					   enum devlink_rate_type type)
+{
+	struct nlattr **attrs = info->attrs;
+
+	if (type == DEVLINK_RATE_TYPE_LEAF) {
+		if (attrs[DEVLINK_ATTR_RATE_TX_SHARE] && !ops->rate_leaf_tx_share_set) {
+			NL_SET_ERR_MSG_MOD(info->extack, "TX share set isn't supported for the leafs");
+			return false;
+		}
+		if (attrs[DEVLINK_ATTR_RATE_TX_MAX] && !ops->rate_leaf_tx_max_set) {
+			NL_SET_ERR_MSG_MOD(info->extack, "TX max set isn't supported for the leafs");
+			return false;
+		}
+	} else {
+		WARN_ON("Unknown type of rate object");
+		return false;
+	}
+
+	return true;
+}
+
+static int devlink_nl_cmd_rate_set_doit(struct sk_buff *skb,
+					struct genl_info *info)
+{
+	struct devlink_rate *devlink_rate = info->user_ptr[1];
+	struct devlink *devlink = devlink_rate->devlink;
+	const struct devlink_ops *ops = devlink->ops;
+	int err;
+
+	if (!ops || !devlink_rate_set_ops_supported(ops, info, devlink_rate->type))
+		return -EOPNOTSUPP;
+
+	err = devlink_nl_rate_set(devlink_rate, ops, info);
+
+	if (!err)
+		devlink_rate_notify(devlink_rate, DEVLINK_CMD_RATE_NEW);
+	return err;
+}
+
 static int devlink_nl_sb_fill(struct sk_buff *msg, struct devlink *devlink,
 			      struct devlink_sb *devlink_sb,
 			      enum devlink_command cmd, u32 portid,
@@ -7958,6 +8036,8 @@ static const struct nla_policy devlink_nl_policy[DEVLINK_ATTR_MAX + 1] = {
 	[DEVLINK_ATTR_PORT_PCI_SF_NUMBER] = { .type = NLA_U32 },
 	[DEVLINK_ATTR_PORT_CONTROLLER_NUMBER] = { .type = NLA_U32 },
 	[DEVLINK_ATTR_RATE_TYPE] = { .type = NLA_U16 },
+	[DEVLINK_ATTR_RATE_TX_SHARE] = { .type = NLA_U64 },
+	[DEVLINK_ATTR_RATE_TX_MAX] = { .type = NLA_U64 },
 };
 
 static const struct genl_small_ops devlink_nl_ops[] = {
@@ -7990,6 +8070,12 @@ static const struct genl_small_ops devlink_nl_ops[] = {
 		.internal_flags = DEVLINK_NL_FLAG_NEED_RATE,
 		/* can be retrieved by unprivileged users */
 	},
+	{
+		.cmd = DEVLINK_CMD_RATE_SET,
+		.doit = devlink_nl_cmd_rate_set_doit,
+		.flags = GENL_ADMIN_PERM,
+		.internal_flags = DEVLINK_NL_FLAG_NEED_RATE,
+	},
 	{
 		.cmd = DEVLINK_CMD_PORT_SPLIT,
 		.validate = GENL_DONT_VALIDATE_STRICT | GENL_DONT_VALIDATE_DUMP,