devlink: define enum for attr types of dynamic attributes

Devlink param and health reporter fmsg use attributes with dynamic type
which is determined according to a different type. Currently used values
are NLA_*. The problem is, they are not part of UAPI. They may change
which would cause a break.

To make this future safe, introduce a enum that shadows NLA_* values in
it and is part of UAPI.

Also, this allows to possibly carry types that are unrelated to NLA_*
values.

Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Link: https://patch.msgid.link/20250505114513.53370-3-jiri@resnulli.us
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/Documentation/netlink/specs/devlink.yaml b/Documentation/netlink/specs/devlink.yaml
index bd9726269b4fa7cf9cb0086863206010d868b7dd..05fee1b7fe1936b49effc5f04c1d889420a832fd 100644 (file)
--- a/Documentation/netlink/specs/devlink.yaml
+++ b/Documentation/netlink/specs/devlink.yaml
@@ -202,6 +202,28 @@ definitions:
         name: exception
       -
         name: control
+  -
+    type: enum
+    name: var-attr-type
+    entries:
+      -
+        name: u8
+        value: 1
+      -
+        name: u16
+      -
+        name: u32
+      -
+        name: u64
+      -
+        name: string
+      -
+        name: flag
+      -
+        name: nul_string
+        value: 10
+      -
+        name: binary
 
 attribute-sets:
   -
@@ -498,6 +520,7 @@ attribute-sets:
       -
         name: param-type
         type: u8
+        enum: var-attr-type
 
       # TODO: fill in the attributes in between
 
@@ -592,6 +615,7 @@ attribute-sets:
       -
         name: fmsg-obj-value-type
         type: u8
+        enum: var-attr-type
 
       # TODO: fill in the attributes in between
 

diff --git a/include/uapi/linux/devlink.h b/include/uapi/linux/devlink.h
index 9401aa343673309ca0a9e4cc1eee73de205e946d..a5ee0f13740ab112986a86a2ae9f2d7897c32c50 100644 (file)
--- a/include/uapi/linux/devlink.h
+++ b/include/uapi/linux/devlink.h
@@ -385,6 +385,21 @@ enum devlink_linecard_state {
        DEVLINK_LINECARD_STATE_MAX = __DEVLINK_LINECARD_STATE_MAX - 1
 };
 
+/* Variable attribute type. */
+enum devlink_var_attr_type {
+       /* Following values relate to the internal NLA_* values */
+       DEVLINK_VAR_ATTR_TYPE_U8 = 1,
+       DEVLINK_VAR_ATTR_TYPE_U16,
+       DEVLINK_VAR_ATTR_TYPE_U32,
+       DEVLINK_VAR_ATTR_TYPE_U64,
+       DEVLINK_VAR_ATTR_TYPE_STRING,
+       DEVLINK_VAR_ATTR_TYPE_FLAG,
+       DEVLINK_VAR_ATTR_TYPE_NUL_STRING = 10,
+       DEVLINK_VAR_ATTR_TYPE_BINARY,
+       __DEVLINK_VAR_ATTR_TYPE_CUSTOM_BASE = 0x80,
+       /* Any possible custom types, unrelated to NLA_* values go below */
+};
+
 enum devlink_attr {
        /* don't change the order or add anything between, this is ABI! */
        DEVLINK_ATTR_UNSPEC,

diff --git a/net/devlink/health.c b/net/devlink/health.c
index 57db6799722a9926409ba974d8290ddbfa4eb7bf..95a7a62d85a27c36fc72443a44e9d4c7c33b58c7 100644 (file)
--- a/net/devlink/health.c
+++ b/net/devlink/health.c
@@ -930,18 +930,31 @@ EXPORT_SYMBOL_GPL(devlink_fmsg_binary_pair_put);
 static int
 devlink_fmsg_item_fill_type(struct devlink_fmsg_item *msg, struct sk_buff *skb)
 {
+       enum devlink_var_attr_type var_attr_type;
+
        switch (msg->nla_type) {
        case NLA_FLAG:
+               var_attr_type = DEVLINK_VAR_ATTR_TYPE_FLAG;
+               break;
        case NLA_U8:
+               var_attr_type = DEVLINK_VAR_ATTR_TYPE_U8;
+               break;
        case NLA_U32:
+               var_attr_type = DEVLINK_VAR_ATTR_TYPE_U32;
+               break;
        case NLA_U64:
+               var_attr_type = DEVLINK_VAR_ATTR_TYPE_U64;
+               break;
        case NLA_NUL_STRING:
+               var_attr_type = DEVLINK_VAR_ATTR_TYPE_NUL_STRING;
+               break;
        case NLA_BINARY:
-               return nla_put_u8(skb, DEVLINK_ATTR_FMSG_OBJ_VALUE_TYPE,
-                                 msg->nla_type);
+               var_attr_type = DEVLINK_VAR_ATTR_TYPE_BINARY;
+               break;
        default:
                return -EINVAL;
        }
+       return nla_put_u8(skb, DEVLINK_ATTR_FMSG_OBJ_VALUE_TYPE, var_attr_type);
 }
 
 static int

diff --git a/net/devlink/netlink_gen.c b/net/devlink/netlink_gen.c
index f9786d51f68f9441b0e0f3405ec0ff94fe60b95e..e340d955cf3bce69c031325a2af25ec6fe2a6adc 100644 (file)
--- a/net/devlink/netlink_gen.c
+++ b/net/devlink/netlink_gen.c
@@ -10,6 +10,33 @@
 
 #include <uapi/linux/devlink.h>
 
+/* Sparse enums validation callbacks */
+static int
+devlink_attr_param_type_validate(const struct nlattr *attr,
+                                struct netlink_ext_ack *extack)
+{
+       switch (nla_get_u8(attr)) {
+       case DEVLINK_VAR_ATTR_TYPE_U8:
+               fallthrough;
+       case DEVLINK_VAR_ATTR_TYPE_U16:
+               fallthrough;
+       case DEVLINK_VAR_ATTR_TYPE_U32:
+               fallthrough;
+       case DEVLINK_VAR_ATTR_TYPE_U64:
+               fallthrough;
+       case DEVLINK_VAR_ATTR_TYPE_STRING:
+               fallthrough;
+       case DEVLINK_VAR_ATTR_TYPE_FLAG:
+               fallthrough;
+       case DEVLINK_VAR_ATTR_TYPE_NUL_STRING:
+               fallthrough;
+       case DEVLINK_VAR_ATTR_TYPE_BINARY:
+               return 0;
+       }
+       NL_SET_ERR_MSG_ATTR(extack, attr, "invalid enum value");
+       return -EINVAL;
+}
+
 /* Common nested types */
 const struct nla_policy devlink_dl_port_function_nl_policy[DEVLINK_PORT_FN_ATTR_CAPS + 1] = {
        [DEVLINK_PORT_FUNCTION_ATTR_HW_ADDR] = { .type = NLA_BINARY, },
@@ -273,7 +300,7 @@ static const struct nla_policy devlink_param_set_nl_policy[DEVLINK_ATTR_PARAM_VA
        [DEVLINK_ATTR_BUS_NAME] = { .type = NLA_NUL_STRING, },
        [DEVLINK_ATTR_DEV_NAME] = { .type = NLA_NUL_STRING, },
        [DEVLINK_ATTR_PARAM_NAME] = { .type = NLA_NUL_STRING, },
-       [DEVLINK_ATTR_PARAM_TYPE] = { .type = NLA_U8, },
+       [DEVLINK_ATTR_PARAM_TYPE] = NLA_POLICY_VALIDATE_FN(NLA_U8, &devlink_attr_param_type_validate),
        [DEVLINK_ATTR_PARAM_VALUE_CMODE] = NLA_POLICY_MAX(NLA_U8, 2),
 };
 

diff --git a/net/devlink/param.c b/net/devlink/param.c
index dcf0d1ccebbabe0bb7cbabd4a767508aef4622f8..d0fb7c88bdb818bee8b89fc84b5df028a1be36fe 100644 (file)
--- a/net/devlink/param.c
+++ b/net/devlink/param.c
@@ -167,19 +167,19 @@ static int devlink_param_set(struct devlink *devlink,
 }
 
 static int
-devlink_param_type_to_nla_type(enum devlink_param_type param_type)
+devlink_param_type_to_var_attr_type(enum devlink_param_type param_type)
 {
        switch (param_type) {
        case DEVLINK_PARAM_TYPE_U8:
-               return NLA_U8;
+               return DEVLINK_VAR_ATTR_TYPE_U8;
        case DEVLINK_PARAM_TYPE_U16:
-               return NLA_U16;
+               return DEVLINK_VAR_ATTR_TYPE_U16;
        case DEVLINK_PARAM_TYPE_U32:
-               return NLA_U32;
+               return DEVLINK_VAR_ATTR_TYPE_U32;
        case DEVLINK_PARAM_TYPE_STRING:
-               return NLA_STRING;
+               return DEVLINK_VAR_ATTR_TYPE_STRING;
        case DEVLINK_PARAM_TYPE_BOOL:
-               return NLA_FLAG;
+               return DEVLINK_VAR_ATTR_TYPE_FLAG;
        default:
                return -EINVAL;
        }
@@ -247,7 +247,7 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
        struct devlink_param_gset_ctx ctx;
        struct nlattr *param_values_list;
        struct nlattr *param_attr;
-       int nla_type;
+       int var_attr_type;
        void *hdr;
        int err;
        int i;
@@ -294,10 +294,10 @@ static int devlink_nl_param_fill(struct sk_buff *msg, struct devlink *devlink,
        if (param->generic && nla_put_flag(msg, DEVLINK_ATTR_PARAM_GENERIC))
                goto param_nest_cancel;
 
-       nla_type = devlink_param_type_to_nla_type(param->type);
-       if (nla_type < 0)
+       var_attr_type = devlink_param_type_to_var_attr_type(param->type);
+       if (var_attr_type < 0)
                goto param_nest_cancel;
-       if (nla_put_u8(msg, DEVLINK_ATTR_PARAM_TYPE, nla_type))
+       if (nla_put_u8(msg, DEVLINK_ATTR_PARAM_TYPE, var_attr_type))
                goto param_nest_cancel;
 
        param_values_list = nla_nest_start_noflag(msg,
@@ -420,19 +420,19 @@ devlink_param_type_get_from_info(struct genl_info *info,
                return -EINVAL;
 
        switch (nla_get_u8(info->attrs[DEVLINK_ATTR_PARAM_TYPE])) {
-       case NLA_U8:
+       case DEVLINK_VAR_ATTR_TYPE_U8:
                *param_type = DEVLINK_PARAM_TYPE_U8;
                break;
-       case NLA_U16:
+       case DEVLINK_VAR_ATTR_TYPE_U16:
                *param_type = DEVLINK_PARAM_TYPE_U16;
                break;
-       case NLA_U32:
+       case DEVLINK_VAR_ATTR_TYPE_U32:
                *param_type = DEVLINK_PARAM_TYPE_U32;
                break;
-       case NLA_STRING:
+       case DEVLINK_VAR_ATTR_TYPE_STRING:
                *param_type = DEVLINK_PARAM_TYPE_STRING;
                break;
-       case NLA_FLAG:
+       case DEVLINK_VAR_ATTR_TYPE_FLAG:
                *param_type = DEVLINK_PARAM_TYPE_BOOL;
                break;
        default: