Merge branch 'mauro' into docs-mw

Mauro says:

This series  increases the minimal requirements for Sphinx and Python, and
drop some backward-compatible code from Sphinx extension.

Looking at Sphinx release dates:

	Release 2.4.0 (released Feb 09, 2020)
	Release 2.4.4 (released Mar 05, 2020) (current minimal requirement)
	Release 3.4.0 (released Dec 20, 2020)
	Release 3.4.3 (released Jan 08, 2021)

	(https://www.sphinx-doc.org/en/master/changes/index.html)

And Python release dates, we have:

	Python	Release date
	3.5	2015-09-13    (current minimal requirement)
	3.6	2016-12-23
	3.7 	2018-06-27
	3.8 	2019-10-14
	3.9 	2020-10-05
	3.10	2021-10-04

	(according with https://en.wikipedia.org/w/index.php?title=History_of_Python)

The new minimal requirements are now compatible with the toolset available on Jan, 2021,
e.g.:
	- Sphinx 3.4.3;
	- Python 3.9

The new Sphinx minimal requirement allows dropping all backward-compatible code
we have at kernel-doc and at Sphinx extensions.

The new Python minimal requirement also matches the current required level for
almost  all scripts (*).

Those matches a 4-years old toolchain, which sounds a reasonable period
of time, as Python/Sphinx aren't required for the Kernel build.

(*) Except for a couple scripts inside tools that require python 3.10:

    $ vermin -v $(git ls-files '*.py')|grep 3.10
    !2, 3.10     tools/net/sunrpc/xdrgen/generators/__init__.py
    !2, 3.10     tools/net/sunrpc/xdrgen/generators/program.py
    !2, 3.10     tools/net/sunrpc/xdrgen/subcmds/source.py
    !2, 3.10     tools/net/sunrpc/xdrgen/xdr_ast.py
    !2, 3.10     tools/perf/scripts/python/mem-phys-addr.py
    !2, 3.10     tools/power/cpupower/bindings/python/test_raw_pylibcpupower.py

Such scripts aren't required for Kernel builds, so it should be OK to set minimal
python version to 3.9.

1 files changed, 16 insertions, 113 deletions

diff --git a/scripts/kernel-doc b/scripts/kernel-doc
index 70da9a3369c6..2c77b914d017 100755
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -26,7 +26,7 @@ kernel-doc - Print formatted kernel documentation to stdout
 
  kernel-doc [-h] [-v] [-Werror] [-Wall] [-Wreturn] [-Wshort-desc[ription]] [-Wcontents-before-sections]
    [ -man |
-     -rst [-sphinx-version VERSION] [-enable-lineno] |
+     -rst [-enable-lineno] |
      -none
    ]
    [
@@ -130,7 +130,6 @@ if ($#ARGV == -1) {
 }
 
 my $kernelversion;
-my ($sphinx_major, $sphinx_minor, $sphinx_patch);
 
 my $dohighlight = "";
 
@@ -347,23 +346,6 @@ while ($ARGV[0] =~ m/^--?(.*)/) {
         $enable_lineno = 1;
     } elsif ($cmd eq 'show-not-found') {
         $show_not_found = 1;  # A no-op but don't fail
-    } elsif ($cmd eq "sphinx-version") {
-        my $ver_string = shift @ARGV;
-        if ($ver_string =~ m/^(\d+)(\.\d+)?(\.\d+)?/) {
-            $sphinx_major = $1;
-            if (defined($2)) {
-                $sphinx_minor = substr($2,1);
-            } else {
-                $sphinx_minor = 0;
-            }
-            if (defined($3)) {
-                $sphinx_patch = substr($3,1)
-            } else {
-                $sphinx_patch = 0;
-            }
-        } else {
-            die "Sphinx version should either major.minor or major.minor.patch format\n";
-        }
     } else {
         # Unknown argument
         pod2usage(
@@ -387,8 +369,6 @@ while ($ARGV[0] =~ m/^--?(.*)/) {
 
 # continue execution near EOF;
 
-# The C domain dialect changed on Sphinx 3. So, we need to check the
-# version in order to produce the right tags.
 sub findprog($)
 {
     foreach(split(/:/, $ENV{PATH})) {
@@ -396,42 +376,6 @@ sub findprog($)
     }
 }
 
-sub get_sphinx_version()
-{
-    my $ver;
-
-    my $cmd = "sphinx-build";
-    if (!findprog($cmd)) {
-        my $cmd = "sphinx-build3";
-        if (!findprog($cmd)) {
-            $sphinx_major = 1;
-            $sphinx_minor = 2;
-            $sphinx_patch = 0;
-            printf STDERR "Warning: Sphinx version not found. Using default (Sphinx version %d.%d.%d)\n",
-                   $sphinx_major, $sphinx_minor, $sphinx_patch;
-            return;
-        }
-    }
-
-    open IN, "$cmd --version 2>&1 |";
-    while (<IN>) {
-        if (m/^\s*sphinx-build\s+([\d]+)\.([\d\.]+)(\+\/[\da-f]+)?$/) {
-            $sphinx_major = $1;
-            $sphinx_minor = $2;
-            $sphinx_patch = $3;
-            last;
-        }
-        # Sphinx 1.2.x uses a different format
-        if (m/^\s*Sphinx.*\s+([\d]+)\.([\d\.]+)$/) {
-            $sphinx_major = $1;
-            $sphinx_minor = $2;
-            $sphinx_patch = $3;
-            last;
-        }
-    }
-    close IN;
-}
-
 # get kernel version from env
 sub get_kernel_version() {
     my $version = 'unknown kernel version';
@@ -859,9 +803,10 @@ sub output_function_rst(%) {
     	$signature .= ")";
     }
 
-    if ($sphinx_major < 3) {
+    if ($args{'typedef'} || $args{'functiontype'} eq "") {
+        print ".. c:macro:: ". $args{'function'} . "\n\n";
+
         if ($args{'typedef'}) {
-            print ".. c:type:: ". $args{'function'} . "\n\n";
             print_lineno($declaration_start_line);
             print "   **Typedef**: ";
             $lineprefix = "";
@@ -869,25 +814,10 @@ sub output_function_rst(%) {
             print "\n\n**Syntax**\n\n";
             print "  ``$signature``\n\n";
         } else {
-            print ".. c:function:: $signature\n\n";
+            print "``$signature``\n\n";
         }
     } else {
-        if ($args{'typedef'} || $args{'functiontype'} eq "") {
-            print ".. c:macro:: ". $args{'function'} . "\n\n";
-
-            if ($args{'typedef'}) {
-                print_lineno($declaration_start_line);
-                print "   **Typedef**: ";
-                $lineprefix = "";
-                output_highlight_rst($args{'purpose'});
-                print "\n\n**Syntax**\n\n";
-                print "  ``$signature``\n\n";
-            } else {
-                print "``$signature``\n\n";
-            }
-        } else {
-            print ".. c:function:: $signature\n\n";
-        }
+        print ".. c:function:: $signature\n\n";
     }
 
     if (!$args{'typedef'}) {
@@ -955,13 +885,9 @@ sub output_enum_rst(%) {
     my $count;
     my $outer;
 
-    if ($sphinx_major < 3) {
-        my $name = "enum " . $args{'enum'};
-        print "\n\n.. c:type:: " . $name . "\n\n";
-    } else {
-        my $name = $args{'enum'};
-        print "\n\n.. c:enum:: " . $name . "\n\n";
-    }
+    my $name = $args{'enum'};
+    print "\n\n.. c:enum:: " . $name . "\n\n";
+
     print_lineno($declaration_start_line);
     $lineprefix = "  ";
     output_highlight_rst($args{'purpose'});
@@ -992,11 +918,8 @@ sub output_typedef_rst(%) {
     my $oldprefix = $lineprefix;
     my $name;
 
-    if ($sphinx_major < 3) {
-        $name = "typedef " . $args{'typedef'};
-    } else {
-        $name = $args{'typedef'};
-    }
+    $name = $args{'typedef'};
+
     print "\n\n.. c:type:: " . $name . "\n\n";
     print_lineno($declaration_start_line);
     $lineprefix = "   ";
@@ -1012,17 +935,13 @@ sub output_struct_rst(%) {
     my ($parameter);
     my $oldprefix = $lineprefix;
 
-    if ($sphinx_major < 3) {
-        my $name = $args{'type'} . " " . $args{'struct'};
-        print "\n\n.. c:type:: " . $name . "\n\n";
+    my $name = $args{'struct'};
+    if ($args{'type'} eq 'union') {
+        print "\n\n.. c:union:: " . $name . "\n\n";
     } else {
-        my $name = $args{'struct'};
-        if ($args{'type'} eq 'union') {
-            print "\n\n.. c:union:: " . $name . "\n\n";
-        } else {
-            print "\n\n.. c:struct:: " . $name . "\n\n";
-        }
+        print "\n\n.. c:struct:: " . $name . "\n\n";
     }
+
     print_lineno($declaration_start_line);
     $lineprefix = "  ";
     output_highlight_rst($args{'purpose'});
@@ -2383,11 +2302,6 @@ sub process_file($) {
     close IN_FILE;
 }
 
-
-if ($output_mode eq "rst") {
-    get_sphinx_version() if (!$sphinx_major);
-}
-
 $kernelversion = get_kernel_version();
 
 # generate a sequence of code that will splice in highlighting information
@@ -2454,17 +2368,6 @@ Do not output documentation, only warnings.
 
 =head3 reStructuredText only
 
-=over 8
-
-=item -sphinx-version VERSION
-
-Use the ReST C domain dialect compatible with a specific Sphinx Version.
-
-If not specified, kernel-doc will auto-detect using the sphinx-build version
-found on PATH.
-
-=back
-
 =head2 Output selection (mutually exclusive):
 
 =over 8