[PATCH RFC] scripts: kernel-doc: use a less pedantic markup for funcs on Sphinx 3.x

[Mauro Carvalho Chehab]

Unfortunately, Sphinx 3.x parser for c functions is too pedantic:

	https://github.com/sphinx-doc/sphinx/issues/8241

Making impossible to use it at the Kernel, as otherwise we would
need to add thousands of macros to conf.py, with would require
lots of maintainance.

So, let's instead use the :c:macro notation. This will
produce a worse result, but should provide cross-references and
will remove thousands of warnings when building with newer
versions of Sphinx.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@xxxxxxxxxx>
---

Jon,

With this patch, the html doc builds with Sphinx 3.2.1 reduced from
1705 warnings to 624 ones.

The markup is not as nice as with Sphinx 1.x/2.x, but, IMHO, it is still
decent.

What do you think?

Please notice that this patch will affect the automarkup type used for
functions (with is currently broken anyway, with Sphinx 3.x)

 scripts/kernel-doc | 36 +++++++++++++++++++++++++++---------
 1 file changed, 27 insertions(+), 9 deletions(-)

diff --git a/scripts/kernel-doc b/scripts/kernel-doc
index 48301ff41ec5..5b891e5c6338 100755
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -886,15 +886,29 @@ sub output_function_rst(%) {
     my $oldprefix = $lineprefix;
     my $start = "";
 
-    if ($args{'typedef'}) {
-	print ".. c:function:: ". $args{'function'} . "\n\n";
-	print_lineno($declaration_start_line);
-	print "   **Typedef**: ";
-	$lineprefix = "";
-	output_highlight_rst($args{'purpose'});
-	$start = "\n\n**Syntax**\n\n  ``";
+    if ($sphinx_major < 3) {
+	if ($args{'typedef'}) {
+	    print ".. c:function:: ". $args{'function'} . "\n\n";
+	    print_lineno($declaration_start_line);
+	    print "   **Typedef**: ";
+	    $lineprefix = "";
+	    output_highlight_rst($args{'purpose'});
+	    $start = "\n\n**Syntax**\n\n  ``";
+	} else {
+	    print ".. c:function:: ";
+	}
     } else {
-	print ".. c:function:: ";
+	print ".. c:macro:: ". $args{'function'} . "\n\n";
+
+	if ($args{'typedef'}) {
+	    print_lineno($declaration_start_line);
+	    print "   **Typedef**: ";
+	    $lineprefix = "";
+	    output_highlight_rst($args{'purpose'});
+	    $start = "\n\n**Syntax**\n\n  ``";
+	} else {
+	    print "``";
+	}
     }
     if ($args{'functiontype'} ne "") {
 	$start .= $args{'functiontype'} . " " . $args{'function'} . " (";
@@ -921,7 +935,11 @@ sub output_function_rst(%) {
     if ($args{'typedef'}) {
 	print ");``\n\n";
     } else {
-	print ")\n\n";
+	if ($sphinx_major < 3) {
+	    print ")\n";
+	} else {
+	    print ")``\n\n";
+	}
 	print_lineno($declaration_start_line);
 	$lineprefix = "   ";
 	output_highlight_rst($args{'purpose'});
-- 
2.26.2