Message-ID: <80f85eacc306e62de8c9c68712c653ba290c2ff2.1757262141.git.mchehab+huawei@kernel.org>
Date: Sun,  7 Sep 2025 18:22:22 +0200
From: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
To: Linux Doc Mailing List <linux-doc@...r.kernel.org>
Cc: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
	Jonathan Corbet <corbet@....net>,
	Mauro Carvalho Chehab <mchehab+huawei@...nel.org>,
	Randy Dunlap <rdunlap@...radead.org>,
	linux-kernel@...r.kernel.org
Subject: [PATCH] kernel-doc: add support for handling global variables

Specially on kAPI, sometimes it is desirable to be able to
describe global variables that are part of kAPI.

Documenting vars with Sphinx is simple, as we don't need
to parse a data struct. All we need is the variable
declaration and use natice C domain ::c:var: to format it
for us.

Add support for it.

Link: https://lore.kernel.org/linux-doc/491c3022-cef8-4860-a945-c9c4a3b63c09@infradead.org/T/#m947c25d95cb1d96a394410ab1131dc8e9e5013f1
Suggested-by: Randy Dunlap <rdunlap@...radead.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@...nel.org>
---
 scripts/lib/kdoc/kdoc_output.py | 31 +++++++++++++++++++++++++++++++
 scripts/lib/kdoc/kdoc_parser.py | 25 ++++++++++++++++++++++++-
 2 files changed, 55 insertions(+), 1 deletion(-)

diff --git a/scripts/lib/kdoc/kdoc_output.py b/scripts/lib/kdoc/kdoc_output.py
index 1eca9a918558..405a5c407522 100644
--- a/scripts/lib/kdoc/kdoc_output.py
+++ b/scripts/lib/kdoc/kdoc_output.py
@@ -199,6 +199,10 @@ class OutputFormat:
             self.out_enum(fname, name, args)
             return self.data
 
+        if dtype == "global":
+            self.out_global(fname, name, args)
+            return self.data
+
         if dtype == "typedef":
             self.out_typedef(fname, name, args)
             return self.data
@@ -227,6 +231,9 @@ class OutputFormat:
     def out_enum(self, fname, name, args):
         """Outputs an enum"""
 
+    def out_global(self, fname, name, args):
+        """Outputs a global variable"""
+
     def out_typedef(self, fname, name, args):
         """Outputs a typedef"""
 
@@ -472,6 +479,18 @@ class RestFormat(OutputFormat):
         self.lineprefix = oldprefix
         self.out_section(args)
 
+    def out_global(self, fname, name, args):
+        oldprefix = self.lineprefix
+        ln = args.declaration_start_line
+        prototype = args.other_stuff["var_type"]
+
+        self.data += f"

.. c:var:: {prototype}

"
+
+        self.print_lineno(ln)
+        self.lineprefix = "  "
+        self.output_highlight(args.get('purpose', ''))
+        self.data += "
"
+
     def out_typedef(self, fname, name, args):
 
         oldprefix = self.lineprefix
@@ -772,6 +791,18 @@ class ManFormat(OutputFormat):
             self.data += f'.SH "{section}"' + "
"
             self.output_highlight(text)
 
+    def out_global(self, fname, name, args):
+        out_name = self.arg_name(args, name)
+        prototype = args.other_stuff["var_type"]
+
+        self.data += f'.TH "{self.modulename}" 9 "{out_name}" "{self.man_date}" "API Manual" LINUX' + "
"
+
+        self.data += ".SH NAME
"
+        self.data += f"{prototype} \- {args['purpose']}
"
+
+        self.data += ".SH SYNOPSIS
"
+        self.data += f"enum {name}" + " {
"
+
     def out_typedef(self, fname, name, args):
         module = self.modulename
         purpose = args.get('purpose')
diff --git a/scripts/lib/kdoc/kdoc_parser.py b/scripts/lib/kdoc/kdoc_parser.py
index 574972e1f741..e2a3f4574894 100644
--- a/scripts/lib/kdoc/kdoc_parser.py
+++ b/scripts/lib/kdoc/kdoc_parser.py
@@ -64,7 +64,7 @@ type_param = KernRe(r"@(\w*((\.\w+)|(->\w+))*(\.\.\.)?)", cache=False)
 # Tests for the beginning of a kerneldoc block in its various forms.
 #
 doc_block = doc_com + KernRe(r'DOC:\s*(.*)?', cache=False)
-doc_begin_data = KernRe(r"^\s*\*?\s*(struct|union|enum|typedef).\s*(\w*)", cache = False)
+doc_begin_data = KernRe(r"^\s*\*?\s*(struct|union|enum|typedef|global).\s*(\w*)", cache = False)
 doc_begin_func = KernRe(str(doc_com) +			# initial " * '
                         r"(?:\w+\s*\*\s*)?" + 		# type (not captured)
                         r'(?:define\s+)?' + 		# possible "define" (not captured)
@@ -886,6 +886,27 @@ class KernelDoc:
         self.output_declaration('enum', declaration_name,
                                 purpose=self.entry.declaration_purpose)
 
+    def dump_global(self, ln, proto):
+        """
+        Stores global variables that are part of kAPI.
+        """
+        VAR_ATTRIBS = [
+            "extern",
+        ]
+        OPTIONAL_VAR_ATTR = "^(?:" + "|".join(VAR_ATTRIBS) + ")?"
+
+        r= KernRe(OPTIONAL_VAR_ATTR + r"(\w.*)\s+([\w_]+)[\d\]\[]*\s*;(?:#.*)?$")
+        if not r.match(proto):
+           self.emit_msg(ln,f"{proto}: can't parse variable")
+           return
+
+        declaration_name = r.group(2)
+        var_type = r.group(0)
+
+        self.output_declaration("global", declaration_name,
+                                var_type=var_type,
+                                purpose=self.entry.declaration_purpose)
+
     def dump_declaration(self, ln, prototype):
         """
         Stores a data declaration inside self.entries array.
@@ -897,6 +918,8 @@ class KernelDoc:
             self.dump_typedef(ln, prototype)
         elif self.entry.decl_type in ["union", "struct"]:
             self.dump_struct(ln, prototype)
+        elif self.entry.decl_type == "global":
+            self.dump_global(ln, prototype)
         else:
             # This would be a bug
             self.emit_message(ln, f'Unknown declaration type: {self.entry.decl_type}')
-- 
2.51.0

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