[PATCH net-next 03/11] net: core: devlink: add port_params_ops for devlink port parameters altering

[Oleksandr Mazur <oleksandr.mazur@plvision.eu>]

Current design makes it impossible to distinguish which port's parameter
should get altered (set) or retrieved (get) whenever there's a single
parameter registered within a few ports.

Change this by adding new devlink port parameter ops structure:
  - introduce structure port_params_ops that has callbacks for
    get/set/validate;
  - if devlink has registered port_params_ops, then upon every devlink
    port parameter get/set call invoke port parameters callback

Suggested-by: Vadym Kochan <vadym.kochan@plvision.eu>
Signed-off-by: Oleksandr Mazur <oleksandr.mazur@plvision.eu>
---
 include/net/devlink.h | 23 ++++++++++++++++++++++
 net/core/devlink.c    | 44 +++++++++++++++++++++++++++++++++++--------
 2 files changed, 59 insertions(+), 8 deletions(-)

diff --git a/include/net/devlink.h b/include/net/devlink.h
index b8c6bac067a6..1d687651260c 100644
--- a/include/net/devlink.h
+++ b/include/net/devlink.h
@@ -1191,6 +1191,28 @@ enum devlink_trap_group_generic_id {
 		.min_burst = _min_burst,				      \
 	}
 
+/**
+ * struct devlink_port_param_ops - devlink port parameters-specific ops
+ * @get: get port parameter value, used for runtime and permanent
+ *       configuration modes
+ * @set: set port parameter value, used for runtime and permanent
+ *       configuration modes
+ * @validate: validate input value is applicable (within value range, etc.)
+ *
+ * This struct should be used by the driver register port parameters ops,
+ * that would be used by the devlink subsystem to fetch (get) or alter (set)
+ * devlink port parameter.
+ */
+struct devlink_port_param_ops {
+	int (*get)(struct devlink_port *port, u32 id,
+		   struct devlink_param_gset_ctx *ctx);
+	int (*set)(struct devlink_port *port, u32 id,
+		   struct devlink_param_gset_ctx *ctx);
+	int (*validate)(struct devlink_port *port, u32 id,
+			union devlink_param_value val,
+			struct netlink_ext_ack *extack);
+};
+
 struct devlink_ops {
 	/**
 	 * @supported_flash_update_params:
@@ -1463,6 +1485,7 @@ struct devlink_ops {
 				 struct devlink_port *port,
 				 enum devlink_port_fn_state state,
 				 struct netlink_ext_ack *extack);
+	const struct devlink_port_param_ops *port_param_ops;
 };
 
 static inline void *devlink_priv(struct devlink *devlink)
diff --git a/net/core/devlink.c b/net/core/devlink.c
index 2baf8720bb48..79566a04083b 100644
--- a/net/core/devlink.c
+++ b/net/core/devlink.c
@@ -3923,6 +3923,7 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
 	const struct devlink_param *param = param_item->param;
 	struct devlink_param_gset_ctx ctx;
 	struct nlattr *param_values_list;
+	struct devlink_port *dl_port;
 	struct nlattr *param_attr;
 	int nla_type;
 	void *hdr;
@@ -3941,7 +3942,20 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
 			if (!param_item->published)
 				continue;
 			ctx.cmode = i;
-			err = devlink_param_get(devlink, param, &ctx);
+			if ((cmd == DEVLINK_CMD_PORT_PARAM_GET ||
+			     cmd == DEVLINK_CMD_PORT_PARAM_NEW ||
+			     cmd == DEVLINK_CMD_PORT_PARAM_DEL) &&
+			     devlink->ops->port_param_ops &&
+			     devlink->ops->port_param_ops->get) {
+				dl_port = devlink_port_get_by_index(devlink,
+								    port_index);
+				err = devlink->ops->port_param_ops->get(dl_port,
+									param->id,
+									&ctx);
+			} else {
+				err = devlink_param_get(devlink, param, &ctx);
+			}
+
 			if (err)
 				return err;
 			param_value[i] = ctx.val;
@@ -4201,6 +4215,7 @@ static int __devlink_nl_cmd_param_set_doit(struct devlink *devlink,
 	struct devlink_param_item *param_item;
 	const struct devlink_param *param;
 	union devlink_param_value value;
+	struct devlink_port *dl_port;
 	int err = 0;
 
 	param_item = devlink_param_get_from_info(param_list, info);
@@ -4234,13 +4249,28 @@ static int __devlink_nl_cmd_param_set_doit(struct devlink *devlink,
 			param_item->driverinit_value = value;
 		param_item->driverinit_value_valid = true;
 	} else {
-		if (!param->set)
-			return -EOPNOTSUPP;
 		ctx.val = value;
 		ctx.cmode = cmode;
-		err = devlink_param_set(devlink, param, &ctx);
-		if (err)
-			return err;
+
+		if ((cmd == DEVLINK_CMD_PORT_PARAM_SET ||
+		     cmd == DEVLINK_CMD_PORT_PARAM_NEW) &&
+		    devlink->ops->port_param_ops &&
+		    devlink->ops->port_param_ops->set) {
+			dl_port = devlink_port_get_by_index(devlink,
+							    port_index);
+			err = devlink->ops->port_param_ops->set(dl_port,
+								param->id,
+								&ctx);
+			if (err)
+				return err;
+		} else {
+			if (!param->set)
+				return -EOPNOTSUPP;
+
+			err = devlink_param_set(devlink, param, &ctx);
+			if (err)
+				return err;
+		}
 	}
 
 	devlink_param_notify(devlink, port_index, param_item, cmd);
@@ -4269,8 +4299,6 @@ static int devlink_param_register_one(struct devlink *devlink,
 
 	if (param->supported_cmodes == BIT(DEVLINK_PARAM_CMODE_DRIVERINIT))
 		WARN_ON(param->get || param->set);
-	else
-		WARN_ON(!param->get || !param->set);
 
 	param_item = kzalloc(sizeof(*param_item), GFP_KERNEL);
 	if (!param_item)
-- 
2.17.1