devlink: Add port-specific option to resource dump doit

Allow querying devlink resources per-port via the resource-dump doit
handler. When a port-index attribute is provided, only that port's
resources are returned. When no port-index is given, only device-level
resources are returned, preserving backward compatibility.

Signed-off-by: Or Har-Toov <ohartoov@nvidia.com>
Reviewed-by: Moshe Shemesh <moshe@nvidia.com>
Signed-off-by: Tariq Toukan <tariqt@nvidia.com>
Link: https://patch.msgid.link/20260407194107.148063-8-tariqt@nvidia.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

3 files changed, 21 insertions, 6 deletions

diff --git a/net/devlink/netlink_gen.c b/net/devlink/netlink_gen.c
index a5a47a4c6de8..9cc372d9ee41 100644
--- a/net/devlink/netlink_gen.c
+++ b/net/devlink/netlink_gen.c
@@ -309,6 +309,7 @@ static const struct nla_policy devlink_resource_dump_do_nl_policy[DEVLINK_ATTR_I
 	[DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
 	[DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
 	[DEVLINK_ATTR_INDEX] = NLA_POLICY_FULL_RANGE(NLA_UINT, &devlink_attr_index_range),
+	[DEVLINK_ATTR_PORT_INDEX] = { .type = NLA_U32, },
 };
 
 /* DEVLINK_CMD_RESOURCE_DUMP - dump */
@@ -962,7 +963,7 @@ const struct genl_split_ops devlink_nl_ops[75] = {
 	{
 		.cmd		= DEVLINK_CMD_RESOURCE_DUMP,
 		.validate	= GENL_DONT_VALIDATE_STRICT,
-		.pre_doit	= devlink_nl_pre_doit,
+		.pre_doit	= devlink_nl_pre_doit_port_optional,
 		.doit		= devlink_nl_resource_dump_doit,
 		.post_doit	= devlink_nl_post_doit,
 		.policy		= devlink_resource_dump_do_nl_policy,
diff --git a/net/devlink/netlink_gen.h b/net/devlink/netlink_gen.h
index d79f6a0888f6..20034b0929a8 100644
--- a/net/devlink/netlink_gen.h
+++ b/net/devlink/netlink_gen.h
@@ -24,11 +24,11 @@ int devlink_nl_pre_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
 			struct genl_info *info);
 int devlink_nl_pre_doit_port(const struct genl_split_ops *ops,
 			     struct sk_buff *skb, struct genl_info *info);
-int devlink_nl_pre_doit_dev_lock(const struct genl_split_ops *ops,
-				 struct sk_buff *skb, struct genl_info *info);
 int devlink_nl_pre_doit_port_optional(const struct genl_split_ops *ops,
 				      struct sk_buff *skb,
 				      struct genl_info *info);
+int devlink_nl_pre_doit_dev_lock(const struct genl_split_ops *ops,
+				 struct sk_buff *skb, struct genl_info *info);
 void
 devlink_nl_post_doit(const struct genl_split_ops *ops, struct sk_buff *skb,
 		     struct genl_info *info);
diff --git a/net/devlink/resource.c b/net/devlink/resource.c
index 7984eda63eb6..bf5221fb3e64 100644
--- a/net/devlink/resource.c
+++ b/net/devlink/resource.c
@@ -251,8 +251,10 @@ static int devlink_resource_list_fill(struct sk_buff *skb,
 static int devlink_resource_fill(struct genl_info *info,
 				 enum devlink_command cmd, int flags)
 {
+	struct devlink_port *devlink_port = info->user_ptr[1];
 	struct devlink *devlink = info->user_ptr[0];
 	struct devlink_resource *resource;
+	struct list_head *resource_list;
 	struct nlattr *resources_attr;
 	struct sk_buff *skb = NULL;
 	struct nlmsghdr *nlh;
@@ -261,7 +263,9 @@ static int devlink_resource_fill(struct genl_info *info,
 	int i;
 	int err;
 
-	resource = list_first_entry(&devlink->resource_list,
+	resource_list = devlink_port ?
+		&devlink_port->resource_list : &devlink->resource_list;
+	resource = list_first_entry(resource_list,
 				    struct devlink_resource, list);
 start_again:
 	err = devlink_nl_msg_reply_and_new(&skb, info);
@@ -277,6 +281,9 @@ start_again:
 
 	if (devlink_nl_put_handle(skb, devlink))
 		goto nla_put_failure;
+	if (devlink_port &&
+	    nla_put_u32(skb, DEVLINK_ATTR_PORT_INDEX, devlink_port->index))
+		goto nla_put_failure;
 
 	resources_attr = nla_nest_start_noflag(skb,
 					       DEVLINK_ATTR_RESOURCE_LIST);
@@ -285,7 +292,7 @@ start_again:
 
 	incomplete = false;
 	i = 0;
-	list_for_each_entry_from(resource, &devlink->resource_list, list) {
+	list_for_each_entry_from(resource, resource_list, list) {
 		err = devlink_resource_put(devlink, skb, resource);
 		if (err) {
 			if (!i)
@@ -319,9 +326,16 @@ err_resource_put:
 
 int devlink_nl_resource_dump_doit(struct sk_buff *skb, struct genl_info *info)
 {
+	struct devlink_port *devlink_port = info->user_ptr[1];
 	struct devlink *devlink = info->user_ptr[0];
+	struct list_head *resource_list;
+
+	if (info->attrs[DEVLINK_ATTR_PORT_INDEX] && !devlink_port)
+		return -ENODEV;
 
-	if (list_empty(&devlink->resource_list))
+	resource_list = devlink_port ?
+		&devlink_port->resource_list : &devlink->resource_list;
+	if (list_empty(resource_list))
 		return -EOPNOTSUPP;
 
 	return devlink_resource_fill(info, DEVLINK_CMD_RESOURCE_DUMP, 0);