Merge branch 'net-tools-ynl-fixes'

Jakub Kicinski says:

====================
tools: ynl: fix subset use and change default value for attrs/ops

Fix a problem in subsetting, which will become apparent when
the devlink family comes after the merge window. Even tho none
of the existing families need this, we don't want someone to
get "inspired" by the current, incorrect code when using specs
in other languages.

Change the default value for the first attr/op. This is a slight
behavior change so needs to go in now. The diffstat of the last
patch should serve as the clearest justification there..
====================
Signed-off-by: David S. Miller <davem@davemloft.net>

Documentation/netlink/specs/ethtool.yaml

@@ -11,7 +11,6 @@ attribute-sets:
       -
         name: dev-index
         type: u32
-        value: 1
       -
         name: dev-name
         type: string
@@ -25,7 +24,6 @@ attribute-sets:
       -
         name: index
         type: u32
-        value: 1
       -
         name: name
         type: string
@@ -39,14 +37,12 @@ attribute-sets:
         name: bit
         type: nest
         nested-attributes: bitset-bit
-        value: 1
   -
     name: bitset
     attributes:
       -
         name: nomask
         type: flag
-        value: 1
       -
         name: size
         type: u32
@@ -61,7 +57,6 @@ attribute-sets:
       -
         name: index
         type: u32
-        value: 1
       -
         name: value
         type: string
@@ -71,7 +66,6 @@ attribute-sets:
       -
         name: string
         type: nest
-        value: 1
         multi-attr: true
         nested-attributes: string
   -
@@ -80,7 +74,6 @@ attribute-sets:
       -
         name: id
         type: u32
-        value: 1
       -
         name: count
         type: u32
@@ -96,14 +89,12 @@ attribute-sets:
         name: stringset
         type: nest
         multi-attr: true
-        value: 1
         nested-attributes: stringset
   -
     name: strset
     attributes:
       -
         name: header
-        value: 1
         type: nest
         nested-attributes: header
       -
@@ -119,7 +110,6 @@ attribute-sets:
     attributes:
       -
         name: header
-        value: 1
         type: nest
         nested-attributes: header
       -
@@ -132,7 +122,6 @@ attribute-sets:
     attributes:
       -
         name: header
-        value: 1
         type: nest
         nested-attributes: header
       -
@@ -180,7 +169,6 @@ attribute-sets:
     attributes:
       -
         name: pad
-        value: 1
         type: pad
       -
         name: reassembly-errors
@@ -205,7 +193,6 @@ attribute-sets:
     attributes:
       -
         name: header
-        value: 1
         type: nest
         nested-attributes: header
       -
@@ -251,13 +238,11 @@ operations:
 
       do: &strset-get-op
         request:
-          value: 1
           attributes:
             - header
             - stringsets
             - counts-only
         reply:
-          value: 1
           attributes:
             - header
             - stringsets

Documentation/netlink/specs/fou.yaml

@@ -26,6 +26,7 @@ attribute-sets:
       -
         name: unspec
         type: unused
+        value: 0
       -
         name: port
         type: u16
@@ -71,6 +72,7 @@ operations:
     -
       name: unspec
       doc: unused
+      value: 0
 
     -
       name: add

Documentation/netlink/specs/netdev.yaml

@@ -48,7 +48,6 @@ attribute-sets:
         name: ifindex
         doc: netdev ifindex
         type: u32
-        value: 1
         checks:
           min: 1
       -
@@ -66,7 +65,6 @@ operations:
     -
       name: dev-get
       doc: Get / dump information about a netdev.
-      value: 1
       attribute-set: dev
       do:
         request:

Documentation/userspace-api/netlink/specs.rst

@@ -197,9 +197,15 @@ value
 Numerical attribute ID, used in serialized Netlink messages.
 The ``value`` property can be skipped, in which case the attribute ID
 will be the value of the previous attribute plus one (recursively)
-and ``0`` for the first attribute in the attribute set.
+and ``1`` for the first attribute in the attribute set.
 
-Note that the ``value`` of an attribute is defined only in its main set.
+Attributes (and operations) use ``1`` as the default value for the first
+entry (unlike enums in definitions which start from ``0``) because
+entry ``0`` is almost always reserved as undefined. Spec can explicitly
+set value to ``0`` if needed.
+
+Note that the ``value`` of an attribute is defined only in its main set
+(not in subsets).
 
 enum
 ~~~~

tools/net/ynl/lib/nlspec.py

@@ -95,15 +95,22 @@ class SpecAttrSet(SpecElement):
         self.attrs = collections.OrderedDict()
         self.attrs_by_val = collections.OrderedDict()
 
-        val = 0
-        for elem in self.yaml['attributes']:
-            if 'value' in elem:
-                val = elem['value']
+        if self.subset_of is None:
+            val = 1
+            for elem in self.yaml['attributes']:
+                if 'value' in elem:
+                    val = elem['value']
 
-            attr = self.new_attr(elem, val)
-            self.attrs[attr.name] = attr
-            self.attrs_by_val[attr.value] = attr
-            val += 1
+                attr = self.new_attr(elem, val)
+                self.attrs[attr.name] = attr
+                self.attrs_by_val[attr.value] = attr
+                val += 1
+        else:
+            real_set = family.attr_sets[self.subset_of]
+            for elem in self.yaml['attributes']:
+                attr = real_set[elem['name']]
+                self.attrs[attr.name] = attr
+                self.attrs_by_val[attr.value] = attr
 
     def new_attr(self, elem, value):
         return SpecAttr(self.family, self, elem, value)
@@ -245,7 +252,7 @@ class SpecFamily(SpecElement):
         self._resolution_list.append(elem)
 
     def _dictify_ops_unified(self):
-        val = 0
+        val = 1
         for elem in self.yaml['operations']['list']:
             if 'value' in elem:
                 val = elem['value']
@@ -256,7 +263,7 @@ class SpecFamily(SpecElement):
             self.msgs[op.name] = op
 
     def _dictify_ops_directional(self):
-        req_val = rsp_val = 0
+        req_val = rsp_val = 1
         for elem in self.yaml['operations']['list']:
             if 'notify' in elem:
                 if 'value' in elem:

tools/net/ynl/ynl-gen-c.py

@@ -2044,14 +2044,17 @@ def render_uapi(family, cw):
     max_value = f"({cnt_name} - 1)"
 
     uapi_enum_start(family, cw, family['operations'], 'enum-name')
+    val = 0
     for op in family.msgs.values():
         if separate_ntf and ('notify' in op or 'event' in op):
             continue
 
         suffix = ','
-        if 'value' in op:
-            suffix = f" = {op['value']},"
+        if op.value != val:
+            suffix = f" = {op.value},"
+            val = op.value
         cw.p(op.enum_name + suffix)
+        val += 1
     cw.nl()
     cw.p(cnt_name + ('' if max_by_define else ','))
     if not max_by_define: