[PATCH v8 11/24] tools/docs: sphinx-build-wrapper: add a wrapper for sphinx-build

[PATCH v8 11/24] tools/docs: sphinx-build-wrapper: add a wrapper for sphinx-build

[Mauro Carvalho Chehab]

There are too much magic inside docs Makefile to properly run
sphinx-build. Create an ancillary script that contains all
kernel-related sphinx-build call logic currently at Makefile.

Such script is designed to work both as an standalone command
and as part of a Makefile. As such, it properly handles POSIX
jobserver used by GNU make.

On a side note, there was a line number increase due to the
conversion (ignoring comments) is:

 Documentation/Makefile          |  131 +++----------
 tools/docs/sphinx-build-wrapper |  293 +++++++++++++++++++++++++++++++
 2 files changed, 323 insertions(+), 101 deletions(-)

Comments and descriptions adds:
 tools/docs/sphinx-build-wrapper | 261 +++++++++++++++++++++++++++++++-

So, about half of the script are comments/descriptions.

This is because some things are more verbosed on Python and because
it requires reading env vars from Makefile. Besides it, this script
has some extra features that don't exist at the Makefile:

- It can be called directly from command line;
- It properly return PDF build errors.

When running the script alone, it will only take handle sphinx-build
targets. On other words, it won't runn make rustdoc after building
htmlfiles, nor it will run the extra check scripts.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 Documentation/Makefile          | 129 ++-----
 tools/docs/sphinx-build-wrapper | 599 ++++++++++++++++++++++++++++++++
 2 files changed, 627 insertions(+), 101 deletions(-)
 create mode 100755 tools/docs/sphinx-build-wrapper

diff --git a/Documentation/Makefile b/Documentation/Makefile
index fd6399c79fab..380284026c13 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -23,21 +23,22 @@ SPHINXOPTS    =
 SPHINXDIRS    = .
 DOCS_THEME    =
 DOCS_CSS      =
-_SPHINXDIRS   = $(sort $(patsubst $(srctree)/Documentation/%/index.rst,%,$(wildcard $(srctree)/Documentation/*/index.rst)))
 SPHINX_CONF   = conf.py
 PAPER         =
 BUILDDIR      = $(obj)/output
 PDFLATEX      = xelatex
 LATEXOPTS     = -interaction=batchmode -no-shell-escape
 
+PYTHONPYCACHEPREFIX ?= $(abspath $(BUILDDIR)/__pycache__)
+
+# Wrapper for sphinx-build
+
+BUILD_WRAPPER = $(srctree)/tools/docs/sphinx-build-wrapper
+
 # For denylisting "variable font" files
 # Can be overridden by setting as an env variable
 FONTS_CONF_DENY_VF ?= $(HOME)/deny-vf
 
-ifeq ($(findstring 1, $(KBUILD_VERBOSE)),)
-SPHINXOPTS    += "-q"
-endif
-
 # User-friendly check for sphinx-build
 HAVE_SPHINX := $(shell if which $(SPHINXBUILD) >/dev/null 2>&1; then echo 1; else echo 0; fi)
 
@@ -51,63 +52,29 @@ ifeq ($(HAVE_SPHINX),0)
 
 else # HAVE_SPHINX
 
-# User-friendly check for pdflatex and latexmk
-HAVE_PDFLATEX := $(shell if which $(PDFLATEX) >/dev/null 2>&1; then echo 1; else echo 0; fi)
-HAVE_LATEXMK := $(shell if which latexmk >/dev/null 2>&1; then echo 1; else echo 0; fi)
+# Common documentation targets
+infodocs texinfodocs latexdocs epubdocs xmldocs pdfdocs linkcheckdocs:
+	$(Q)@$(srctree)/tools/docs/sphinx-pre-install --version-check
+	+$(Q)$(PYTHON3) $(BUILD_WRAPPER) $@ \
+		--sphinxdirs="$(SPHINXDIRS)" --conf="$(SPHINX_CONF)" \
+		--builddir="$(BUILDDIR)" --deny-vf=$(FONTS_CONF_DENY_VF) \
+		--theme=$(DOCS_THEME) --css=$(DOCS_CSS) --paper=$(PAPER)
 
-ifeq ($(HAVE_LATEXMK),1)
-	PDFLATEX := latexmk -$(PDFLATEX)
-endif #HAVE_LATEXMK
-
-# Internal variables.
-PAPEROPT_a4     = -D latex_elements.papersize=a4paper
-PAPEROPT_letter = -D latex_elements.papersize=letterpaper
-ALLSPHINXOPTS   = -D kerneldoc_srctree=$(srctree) -D kerneldoc_bin=$(KERNELDOC)
-ALLSPHINXOPTS   += $(PAPEROPT_$(PAPER)) $(SPHINXOPTS)
-ifneq ($(wildcard $(srctree)/.config),)
-ifeq ($(CONFIG_RUST),y)
-	# Let Sphinx know we will include rustdoc
-	ALLSPHINXOPTS   +=  -t rustdoc
-endif
+# Special handling for pdfdocs
+ifneq ($(shell which $(PDFLATEX) >/dev/null 2>&1; echo $$?),0)
+pdfdocs:
+	$(warning The '$(PDFLATEX)' command was not found. Make sure you have it installed and in PATH to produce PDF output.)
+	@echo "  SKIP    Sphinx $@ target."
 endif
-# the i18n builder cannot share the environment and doctrees with the others
-I18NSPHINXOPTS  = $(PAPEROPT_$(PAPER)) $(SPHINXOPTS) .
-
-# commands; the 'cmd' from scripts/Kbuild.include is not *loopable*
-loop_cmd = $(echo-cmd) $(cmd_$(1)) || exit;
-
-# $2 sphinx builder e.g. "html"
-# $3 name of the build subfolder / e.g. "userspace-api/media", used as:
-#    * dest folder relative to $(BUILDDIR) and
-#    * cache folder relative to $(BUILDDIR)/.doctrees
-# $4 dest subfolder e.g. "man" for man pages at userspace-api/media/man
-# $5 reST source folder relative to $(src),
-#    e.g. "userspace-api/media" for the linux-tv book-set at ./Documentation/userspace-api/media
-
-PYTHONPYCACHEPREFIX ?= $(abspath $(BUILDDIR)/__pycache__)
-
-quiet_cmd_sphinx = SPHINX  $@ --> file://$(abspath $(BUILDDIR)/$3/$4)
-      cmd_sphinx = \
-	PYTHONPYCACHEPREFIX="$(PYTHONPYCACHEPREFIX)" \
-	BUILDDIR=$(abspath $(BUILDDIR)) SPHINX_CONF=$(abspath $(src)/$5/$(SPHINX_CONF)) \
-	$(PYTHON3) $(srctree)/scripts/jobserver-exec \
-	$(CONFIG_SHELL) $(srctree)/Documentation/sphinx/parallel-wrapper.sh \
-	$(SPHINXBUILD) \
-	-b $2 \
-	-c $(abspath $(src)) \
-	-d $(abspath $(BUILDDIR)/.doctrees/$3) \
-	-D version=$(KERNELVERSION) -D release=$(KERNELRELEASE) \
-	$(ALLSPHINXOPTS) \
-	$(abspath $(src)/$5) \
-	$(abspath $(BUILDDIR)/$3/$4) && \
-	if [ "x$(DOCS_CSS)" != "x" ]; then \
-		cp $(if $(patsubst /%,,$(DOCS_CSS)),$(abspath $(srctree)/$(DOCS_CSS)),$(DOCS_CSS)) $(BUILDDIR)/$3/_static/; \
-	fi
 
+# HTML main logic is identical to other targets. However, if rust is enabled,
+# an extra step at the end is required to generate rustdoc.
 htmldocs:
-	@$(srctree)/tools/docs/sphinx-pre-install --version-check
-	@+$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,html,$(var),,$(var)))
-
+	$(Q)@$(srctree)/tools/docs/sphinx-pre-install --version-check
+	+$(Q)$(PYTHON3) $(BUILD_WRAPPER) $@ \
+		--sphinxdirs="$(SPHINXDIRS)" --conf="$(SPHINX_CONF)" \
+		--builddir="$(BUILDDIR)" \
+		--theme=$(DOCS_THEME) --css=$(DOCS_CSS) --paper=$(PAPER)
 # If Rust support is available and .config exists, add rustdoc generated contents.
 # If there are any, the errors from this make rustdoc will be displayed but
 # won't stop the execution of htmldocs
@@ -118,49 +85,6 @@ ifeq ($(CONFIG_RUST),y)
 endif
 endif
 
-texinfodocs:
-	@$(srctree)/tools/docs/sphinx-pre-install --version-check
-	@+$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,texinfo,$(var),texinfo,$(var)))
-
-# Note: the 'info' Make target is generated by sphinx itself when
-# running the texinfodocs target define above.
-infodocs: texinfodocs
-	$(MAKE) -C $(BUILDDIR)/texinfo info
-
-linkcheckdocs:
-	@$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,linkcheck,$(var),,$(var)))
-
-latexdocs:
-	@$(srctree)/tools/docs/sphinx-pre-install --version-check
-	@+$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,latex,$(var),latex,$(var)))
-
-ifeq ($(HAVE_PDFLATEX),0)
-
-pdfdocs:
-	$(warning The '$(PDFLATEX)' command was not found. Make sure you have it installed and in PATH to produce PDF output.)
-	@echo "  SKIP    Sphinx $@ target."
-
-else # HAVE_PDFLATEX
-
-pdfdocs: DENY_VF = XDG_CONFIG_HOME=$(FONTS_CONF_DENY_VF)
-pdfdocs: latexdocs
-	@$(srctree)/tools/docs/sphinx-pre-install --version-check
-	$(foreach var,$(SPHINXDIRS), \
-	   $(MAKE) PDFLATEX="$(PDFLATEX)" LATEXOPTS="$(LATEXOPTS)" $(DENY_VF) -C $(BUILDDIR)/$(var)/latex || $(PYTHON3) $(srctree)/tools/docs/check-variable-fonts.py || exit; \
-	   mkdir -p $(BUILDDIR)/$(var)/pdf; \
-	   mv $(subst .tex,.pdf,$(wildcard $(BUILDDIR)/$(var)/latex/*.tex)) $(BUILDDIR)/$(var)/pdf/; \
-	)
-
-endif # HAVE_PDFLATEX
-
-epubdocs:
-	@$(srctree)/tools/docs/sphinx-pre-install --version-check
-	@+$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,epub,$(var),epub,$(var)))
-
-xmldocs:
-	@$(srctree)/tools/docs/sphinx-pre-install --version-check
-	@+$(foreach var,$(SPHINXDIRS),$(call loop_cmd,sphinx,xml,$(var),xml,$(var)))
-
 endif # HAVE_SPHINX
 
 # The following targets are independent of HAVE_SPHINX, and the rules should
@@ -172,6 +96,9 @@ refcheckdocs:
 cleandocs:
 	$(Q)rm -rf $(BUILDDIR)
 
+# Used only on help
+_SPHINXDIRS   = $(sort $(patsubst $(srctree)/Documentation/%/index.rst,%,$(wildcard $(srctree)/Documentation/*/index.rst)))
+
 dochelp:
 	@echo  ' Linux kernel internal documentation in different formats from ReST:'
 	@echo  '  htmldocs        - HTML'
diff --git a/tools/docs/sphinx-build-wrapper b/tools/docs/sphinx-build-wrapper
new file mode 100755
index 000000000000..c57c732b879c
--- /dev/null
+++ b/tools/docs/sphinx-build-wrapper
@@ -0,0 +1,599 @@
+#!/usr/bin/env python3
+# SPDX-License-Identifier: GPL-2.0
+# Copyright (C) 2025 Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
+#
+# pylint: disable=R0902, R0912, R0913, R0914, R0915, R0917, C0103
+#
+# Converted from docs Makefile and parallel-wrapper.sh, both under
+# GPLv2, copyrighted since 2008 by the following authors:
+#
+#    Akira Yokosawa <akiyks@gmail.com>
+#    Arnd Bergmann <arnd@arndb.de>
+#    Breno Leitao <leitao@debian.org>
+#    Carlos Bilbao <carlos.bilbao@amd.com>
+#    Dave Young <dyoung@redhat.com>
+#    Donald Hunter <donald.hunter@gmail.com>
+#    Geert Uytterhoeven <geert+renesas@glider.be>
+#    Jani Nikula <jani.nikula@intel.com>
+#    Jan Stancek <jstancek@redhat.com>
+#    Jonathan Corbet <corbet@lwn.net>
+#    Joshua Clayton <stillcompiling@gmail.com>
+#    Kees Cook <keescook@chromium.org>
+#    Linus Torvalds <torvalds@linux-foundation.org>
+#    Magnus Damm <damm+renesas@opensource.se>
+#    Masahiro Yamada <masahiroy@kernel.org>
+#    Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
+#    Maxim Cournoyer <maxim.cournoyer@gmail.com>
+#    Peter Foley <pefoley2@pefoley.com>
+#    Randy Dunlap <rdunlap@infradead.org>
+#    Rob Herring <robh@kernel.org>
+#    Shuah Khan <shuahkh@osg.samsung.com>
+#    Thorsten Blum <thorsten.blum@toblux.com>
+#    Tomas Winkler <tomas.winkler@intel.com>
+
+
+"""
+Sphinx build wrapper that handles Kernel-specific business rules:
+
+- it gets the Kernel build environment vars;
+- it determines what's the best parallelism;
+- it handles SPHINXDIRS
+
+This tool ensures that MIN_PYTHON_VERSION is satisfied. If version is
+below that, it seeks for a new Python version. If found, it re-runs using
+the newer version.
+"""
+
+import argparse
+import os
+import shlex
+import shutil
+import subprocess
+import sys
+
+from lib.python_version import PythonVersion
+from lib.latex_fonts import LatexFontChecker
+
+LIB_DIR = "../../scripts/lib"
+SRC_DIR = os.path.dirname(os.path.realpath(__file__))
+
+sys.path.insert(0, os.path.join(SRC_DIR, LIB_DIR))
+
+from jobserver import JobserverExec         # pylint: disable=C0413,C0411,E0401
+
+#
+#  Some constants
+#
+MIN_PYTHON_VERSION = PythonVersion("3.7").version
+PAPER = ["", "a4", "letter"]
+
+TARGETS = {
+    "cleandocs":     { "builder": "clean" },
+    "linkcheckdocs": { "builder": "linkcheck" },
+    "htmldocs":      { "builder": "html" },
+    "epubdocs":      { "builder": "epub",    "out_dir": "epub" },
+    "texinfodocs":   { "builder": "texinfo", "out_dir": "texinfo" },
+    "infodocs":      { "builder": "texinfo", "out_dir": "texinfo" },
+    "latexdocs":     { "builder": "latex",   "out_dir": "latex" },
+    "pdfdocs":       { "builder": "latex",   "out_dir": "latex" },
+    "xmldocs":       { "builder": "xml",     "out_dir": "xml" },
+}
+
+
+#
+# SphinxBuilder class
+#
+
+class SphinxBuilder:
+    """
+    Handles a sphinx-build target, adding needed arguments to build
+    with the Kernel.
+    """
+
+    def is_rust_enabled(self):
+        """Check if rust is enabled at .config"""
+        config_path = os.path.join(self.srctree, ".config")
+        if os.path.isfile(config_path):
+            with open(config_path, "r", encoding="utf-8") as f:
+                return "CONFIG_RUST=y" in f.read()
+        return False
+
+    def get_path(self, path, use_cwd=False, abs_path=False):
+        """
+        Ancillary routine to handle patches the right way, as shell does.
+
+        It first expands "~" and "~user". Then, if patch is not absolute,
+        join self.srctree. Finally, if requested, convert to abspath.
+        """
+
+        path = os.path.expanduser(path)
+        if not path.startswith("/"):
+            if use_cwd:
+                base = os.getcwd()
+            else:
+                base = self.srctree
+
+            path = os.path.join(base, path)
+
+        if abs_path:
+            return os.path.abspath(path)
+
+        return path
+
+    def get_sphinx_extra_opts(self, n_jobs):
+        """
+        Get the number of jobs to be used for docs build passed via command
+        line and desired sphinx verbosity.
+
+        The number of jobs can be on different places:
+
+        1) It can be passed via "-j" argument;
+        2) The SPHINXOPTS="-j8" env var may have "-j";
+        3) if called via GNU make, -j specifies the desired number of jobs.
+           with GNU makefile, this number is available via POSIX jobserver;
+        4) if none of the above is available, it should default to "-jauto",
+           and let sphinx decide the best value.
+        """
+
+        #
+        # SPHINXOPTS env var, if used, contains extra arguments to be used
+        # by sphinx-build time. Among them, it may contain sphinx verbosity
+        # and desired number of parallel jobs.
+        #
+        parser = argparse.ArgumentParser()
+        parser.add_argument('-j', '--jobs', type=int)
+        parser.add_argument('-q', '--quiet', type=int)
+
+        #
+        # Other sphinx-build arguments go as-is, so place them
+        # at self.sphinxopts, using shell parser
+        #
+        sphinxopts = shlex.split(os.environ.get("SPHINXOPTS", ""))
+
+        #
+        # Build a list of sphinx args, honoring verbosity here if specified
+        #
+
+        verbose = self.verbose
+        sphinx_args, self.sphinxopts = parser.parse_known_args(sphinxopts)
+        if sphinx_args.quiet is True:
+            verbose = False
+
+        #
+        # If the user explicitly sets "-j" at command line, use it.
+        # Otherwise, pick it from SPHINXOPTS args
+        #
+        if n_jobs:
+            self.n_jobs = n_jobs
+        elif sphinx_args.jobs:
+            self.n_jobs = sphinx_args.jobs
+        else:
+            self.n_jobs = None
+
+        if not verbose:
+            self.sphinxopts += ["-q"]
+
+    def __init__(self, builddir, verbose=False, n_jobs=None):
+        """Initialize internal variables"""
+        self.verbose = None
+
+        #
+        # Normal variables passed from Kernel's makefile
+        #
+        self.kernelversion = os.environ.get("KERNELVERSION", "unknown")
+        self.kernelrelease = os.environ.get("KERNELRELEASE", "unknown")
+        self.pdflatex = os.environ.get("PDFLATEX", "xelatex")
+        self.latexopts = os.environ.get("LATEXOPTS", "-interaction=batchmode -no-shell-escape")
+
+        if not verbose:
+            verbose = bool(os.environ.get("KBUILD_VERBOSE", "") != "")
+
+        if verbose is not None:
+            self.verbose = verbose
+
+        #
+        # Source tree directory. This needs to be at os.environ, as
+        # Sphinx extensions use it
+        #
+        self.srctree = os.environ.get("srctree")
+        if not self.srctree:
+            self.srctree = "."
+            os.environ["srctree"] = self.srctree
+
+        #
+        # Now that we can expand srctree, get other directories as well
+        #
+        self.sphinxbuild = os.environ.get("SPHINXBUILD", "sphinx-build")
+        self.kerneldoc = self.get_path(os.environ.get("KERNELDOC",
+                                                      "scripts/kernel-doc.py"))
+        self.builddir = self.get_path(builddir, use_cwd=True, abs_path=True)
+
+        self.config_rust = self.is_rust_enabled()
+
+        #
+        # Get directory locations for LaTeX build toolchain
+        #
+        self.pdflatex_cmd = shutil.which(self.pdflatex)
+        self.latexmk_cmd = shutil.which("latexmk")
+
+        self.env = os.environ.copy()
+
+        self.get_sphinx_extra_opts(n_jobs)
+
+    def run_sphinx(self, sphinx_build, build_args, *args, **pwargs):
+        """
+        Executes sphinx-build using current python3 command.
+
+        When calling via GNU make, POSIX jobserver is used to tell how
+        many jobs are still available from a job pool. claim all remaining
+        jobs, as we don't want sphinx-build to run in parallel with other
+        jobs.
+
+        Despite that, the user may actually force a different value than
+        the number of available jobs via command line.
+
+        The "with" logic here is used to ensure that the claimed jobs will
+        be freed once subprocess finishes
+        """
+
+        with JobserverExec() as jobserver:
+            if jobserver.claim:
+                #
+                # when GNU make is used, claim available jobs from jobserver
+                #
+                n_jobs = str(jobserver.claim)
+            else:
+                #
+                # Otherwise, let sphinx decide by default
+                #
+                n_jobs = "auto"
+
+            #
+            # If explicitly requested via command line, override default
+            #
+            if self.n_jobs:
+                n_jobs = str(self.n_jobs)
+
+            cmd = [sys.executable, sphinx_build]
+            cmd += [f"-j{n_jobs}"]
+            cmd += self.sphinxopts
+            cmd += build_args
+
+            if self.verbose:
+                print(" ".join(cmd))
+
+            return subprocess.call(cmd, *args, **pwargs)
+
+    def handle_html(self, css, output_dir):
+        """
+        Extra steps for HTML and epub output.
+
+        For such targets, we need to ensure that CSS will be properly
+        copied to the output _static directory
+        """
+
+        if not css:
+            return
+
+        css = os.path.expanduser(css)
+        if not css.startswith("/"):
+            css = os.path.join(self.srctree, css)
+
+        static_dir = os.path.join(output_dir, "_static")
+        os.makedirs(static_dir, exist_ok=True)
+
+        try:
+            shutil.copy2(css, static_dir)
+        except (OSError, IOError) as e:
+            print(f"Warning: Failed to copy CSS: {e}", file=sys.stderr)
+
+    def handle_pdf(self, output_dirs, deny_vf):
+        """
+        Extra steps for PDF output.
+
+        As PDF is handled via a LaTeX output, after building the .tex file,
+        a new build is needed to create the PDF output from the latex
+        directory.
+        """
+        builds = {}
+        max_len = 0
+
+        #
+        # Since early 2024, Fedora and openSUSE tumbleweed have started
+        # deploying variable-font format of "Noto CJK", causing LaTeX
+        # to break with CJK. Work around it, by denying the variable font
+        # usage during xelatex build by passing the location of a config
+        # file with a deny list.
+        #
+        # See tools/docs/lib/latex_fonts.py for more details.
+        #
+        if deny_vf:
+            deny_vf = os.path.expanduser(deny_vf)
+            if os.path.isdir(deny_vf):
+                self.env["XDG_CONFIG_HOME"] = deny_vf
+
+        for from_dir in output_dirs:
+            pdf_dir = os.path.join(from_dir, "../pdf")
+            os.makedirs(pdf_dir, exist_ok=True)
+
+            if self.latexmk_cmd:
+                latex_cmd = [self.latexmk_cmd, f"-{self.pdflatex}"]
+            else:
+                latex_cmd = [self.pdflatex]
+
+            latex_cmd.extend(shlex.split(self.latexopts))
+
+            tex_suffix = ".tex"
+
+            #
+            # Process each .tex file
+            #
+
+            has_tex = False
+            build_failed = False
+            with os.scandir(from_dir) as it:
+                for entry in it:
+                    if not entry.name.endswith(tex_suffix):
+                        continue
+
+                    name = entry.name[:-len(tex_suffix)]
+                    has_tex = True
+
+                    #
+                    # LaTeX PDF error code is almost useless for us:
+                    # any warning makes it non-zero. For kernel doc builds it
+                    # always return non-zero even when build succeeds.
+                    # So, let's do the best next thing: check if all PDF
+                    # files were built. If they're, print a summary and
+                    # return 0 at the end of this function
+                    #
+                    try:
+                        subprocess.run(latex_cmd + [entry.path],
+                                       cwd=from_dir, check=True, env=self.env)
+                    except subprocess.CalledProcessError:
+                        pass
+
+                    pdf_name = name + ".pdf"
+                    pdf_from = os.path.join(from_dir, pdf_name)
+                    pdf_to = os.path.join(pdf_dir, pdf_name)
+
+                    if os.path.exists(pdf_from):
+                        os.rename(pdf_from, pdf_to)
+                        builds[name] = os.path.relpath(pdf_to, self.builddir)
+                    else:
+                        builds[name] = "FAILED"
+                        build_failed = True
+
+                    name = entry.name.removesuffix(".tex")
+                    max_len = max(max_len, len(name))
+
+            if not has_tex:
+                name = os.path.basename(from_dir)
+                max_len = max(max_len, len(name))
+                builds[name] = "FAILED (no .tex)"
+                build_failed = True
+
+        msg = "Summary"
+        msg += "\n" + "=" * len(msg)
+        print()
+        print(msg)
+
+        for pdf_name, pdf_file in builds.items():
+            print(f"{pdf_name:<{max_len}}: {pdf_file}")
+
+        print()
+
+        if build_failed:
+            msg = LatexFontChecker().check()
+            if msg:
+                print(msg)
+
+            sys.exit("PDF build failed: not all PDF files were created.")
+        else:
+            print("All PDF files were built.")
+
+    def handle_info(self, output_dirs):
+        """
+        Extra steps for Info output.
+
+        For texinfo generation, an additional make is needed from the
+        texinfo directory.
+        """
+
+        for output_dir in output_dirs:
+            try:
+                subprocess.run(["make", "info"], cwd=output_dir, check=True)
+            except subprocess.CalledProcessError as e:
+                sys.exit(f"Error generating info docs: {e}")
+
+    def cleandocs(self, builder):           # pylint: disable=W0613
+        """Remove documentation output directory"""
+        shutil.rmtree(self.builddir, ignore_errors=True)
+
+    def build(self, target, sphinxdirs=None, conf="conf.py",
+              theme=None, css=None, paper=None, deny_vf=None):
+        """
+        Build documentation using Sphinx. This is the core function of this
+        module. It prepares all arguments required by sphinx-build.
+        """
+
+        builder = TARGETS[target]["builder"]
+        out_dir = TARGETS[target].get("out_dir", "")
+
+        #
+        # Cleandocs doesn't require sphinx-build
+        #
+        if target == "cleandocs":
+            self.cleandocs(builder)
+            return
+
+        if theme:
+            os.environ["DOCS_THEME"] = theme
+
+        #
+        # Other targets require sphinx-build, so check if it exists
+        #
+        sphinxbuild = shutil.which(self.sphinxbuild, path=self.env["PATH"])
+        if not sphinxbuild:
+            sys.exit(f"Error: {self.sphinxbuild} not found in PATH.\n")
+
+        if builder == "latex":
+            if not self.pdflatex_cmd and not self.latexmk_cmd:
+                sys.exit("Error: pdflatex or latexmk required for PDF generation")
+
+        docs_dir = os.path.abspath(os.path.join(self.srctree, "Documentation"))
+
+        #
+        # Fill in base arguments for Sphinx build
+        #
+        kerneldoc = self.kerneldoc
+        if kerneldoc.startswith(self.srctree):
+            kerneldoc = os.path.relpath(kerneldoc, self.srctree)
+
+        args = [ "-b", builder, "-c", docs_dir ]
+
+        if builder == "latex":
+            if not paper:
+                paper = PAPER[1]
+
+            args.extend(["-D", f"latex_elements.papersize={paper}paper"])
+
+        if self.config_rust:
+            args.extend(["-t", "rustdoc"])
+
+        if conf:
+            self.env["SPHINX_CONF"] = self.get_path(conf, abs_path=True)
+
+        if not sphinxdirs:
+            sphinxdirs = os.environ.get("SPHINXDIRS", ".")
+
+        #
+        # sphinxdirs can be a list or a whitespace-separated string
+        #
+        sphinxdirs_list = []
+        for sphinxdir in sphinxdirs:
+            if isinstance(sphinxdir, list):
+                sphinxdirs_list += sphinxdir
+            else:
+                sphinxdirs_list += sphinxdir.split()
+
+        #
+        # Step 1:  Build each directory in separate.
+        #
+        # This is not the best way of handling it, as cross-references between
+        # them will be broken, but this is what we've been doing since
+        # the beginning.
+        #
+        output_dirs = []
+        for sphinxdir in sphinxdirs_list:
+            src_dir = os.path.join(docs_dir, sphinxdir)
+            doctree_dir = os.path.join(self.builddir, ".doctrees")
+            output_dir = os.path.join(self.builddir, sphinxdir, out_dir)
+
+            #
+            # Make directory names canonical
+            #
+            src_dir = os.path.normpath(src_dir)
+            doctree_dir = os.path.normpath(doctree_dir)
+            output_dir = os.path.normpath(output_dir)
+
+            os.makedirs(doctree_dir, exist_ok=True)
+            os.makedirs(output_dir, exist_ok=True)
+
+            output_dirs.append(output_dir)
+
+            build_args = args + [
+                "-d", doctree_dir,
+                "-D", f"kerneldoc_bin={kerneldoc}",
+                "-D", f"version={self.kernelversion}",
+                "-D", f"release={self.kernelrelease}",
+                "-D", f"kerneldoc_srctree={self.srctree}",
+                src_dir,
+                output_dir,
+            ]
+
+            try:
+                self.run_sphinx(sphinxbuild, build_args, env=self.env)
+            except (OSError, ValueError, subprocess.SubprocessError) as e:
+                sys.exit(f"Build failed: {repr(e)}")
+
+            #
+            # Ensure that each html/epub output will have needed static files
+            #
+            if target in ["htmldocs", "epubdocs"]:
+                self.handle_html(css, output_dir)
+
+        #
+        # Step 2: Some targets (PDF and info) require an extra step once
+        #         sphinx-build finishes
+        #
+        if target == "pdfdocs":
+            self.handle_pdf(output_dirs, deny_vf)
+        elif target == "infodocs":
+            self.handle_info(output_dirs)
+
+def jobs_type(value):
+    """
+    Handle valid values for -j. Accepts Sphinx "-jauto", plus a number
+    equal or bigger than one.
+    """
+    if value is None:
+        return None
+
+    if value.lower() == 'auto':
+        return value.lower()
+
+    try:
+        if int(value) >= 1:
+            return value
+
+        raise argparse.ArgumentTypeError(f"Minimum jobs is 1, got {value}")
+    except ValueError:
+        raise argparse.ArgumentTypeError(f"Must be 'auto' or positive integer, got {value}")  # pylint: disable=W0707
+
+def main():
+    """
+    Main function. The only mandatory argument is the target. If not
+    specified, the other arguments will use default values if not
+    specified at os.environ.
+    """
+    parser = argparse.ArgumentParser(description="Kernel documentation builder")
+
+    parser.add_argument("target", choices=list(TARGETS.keys()),
+                        help="Documentation target to build")
+    parser.add_argument("--sphinxdirs", nargs="+",
+                        help="Specific directories to build")
+    parser.add_argument("--conf", default="conf.py",
+                        help="Sphinx configuration file")
+    parser.add_argument("--builddir", default="output",
+                        help="Sphinx configuration file")
+
+    parser.add_argument("--theme", help="Sphinx theme to use")
+
+    parser.add_argument("--css", help="Custom CSS file for HTML/EPUB")
+
+    parser.add_argument("--paper", choices=PAPER, default=PAPER[0],
+                        help="Paper size for LaTeX/PDF output")
+
+    parser.add_argument('--deny-vf',
+                        help="Configuration to deny variable fonts on pdf builds")
+
+    parser.add_argument("-v", "--verbose", action='store_true',
+                        help="place build in verbose mode")
+
+    parser.add_argument('-j', '--jobs', type=jobs_type,
+                        help="Sets number of jobs to use with sphinx-build")
+
+    args = parser.parse_args()
+
+    PythonVersion.check_python(MIN_PYTHON_VERSION)
+
+    builder = SphinxBuilder(builddir=args.builddir,
+                            verbose=args.verbose, n_jobs=args.jobs)
+
+    builder.build(args.target, sphinxdirs=args.sphinxdirs, conf=args.conf,
+                  theme=args.theme, css=args.css, paper=args.paper,
+                  deny_vf=args.deny_vf)
+
+if __name__ == "__main__":
+    main()
-- 
2.51.0

[PATCH v8 22/24] tools/docs: sphinx-build-wrapper: move rust doc builder to wrapper

[Mauro Carvalho Chehab]

Simplify even further the docs Makefile by moving rust build logic
to the wrapper.

After this change, running make on an environment with rust enabled
works as expected.

With CONFIG_RUST:

    $ make O=/tmp/foo LLVM=1 SPHINXDIRS=peci htmldocs
    make[1]: Entrando no diretório '/tmp/foo'

    Using alabaster theme
    Using Python kernel-doc
      GEN     Makefile
      DESCEND objtool
      CC      arch/x86/kernel/asm-offsets.s
      INSTALL libsubcmd_headers
      CALL    /new_devel/docs/scripts/checksyscalls.sh
      RUSTC L rust/core.o
      BINDGEN rust/bindings/bindings_generated.rs
      BINDGEN rust/bindings/bindings_helpers_generated.rs
    ...

Without it:
    $ make SPHINXDIRS=peci htmldocs
    Using alabaster theme
    Using Python kernel-doc

Both work as it is it is supposed to do.

After the change, it is also possible to build directly with the script
by passing "--rustodoc".

if CONFIG_RUST, this works fine:

    $ ./tools/docs/sphinx-build-wrapper --sphinxdirs peci --rustdoc -- htmldocs
    Using alabaster theme
    Using Python kernel-doc
      SYNC    include/config/auto.conf
    ...
      RUSTC L rust/core.o
    ...

If not, it will produce a warning that RUST may be disabled:

    $ ./tools/docs/sphinx-build-wrapper --sphinxdirs peci --rustdoc -- htmldocs
    Using alabaster theme
    Using Python kernel-doc
    ***
    *** Configuration file ".config" not found!
    ***
    *** Please run some configurator (e.g. "make oldconfig" or
    *** "make menuconfig" or "make xconfig").
    ***
    make[1]: *** [/new_devel/docs/Makefile:829: .config] Error 1
    make: *** [Makefile:248: __sub-make] Error 2
    Ignored errors when building rustdoc: Command '['make', 'LLVM=1', 'rustdoc']' returned non-zero exit status 2.. Is RUST enabled?

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 Documentation/Makefile          | 29 +++++-----------
 tools/docs/sphinx-build-wrapper | 59 ++++++++++++++++++---------------
 2 files changed, 41 insertions(+), 47 deletions(-)

diff --git a/Documentation/Makefile b/Documentation/Makefile
index aa42b2cb7030..b32f68387dfc 100644
--- a/Documentation/Makefile
+++ b/Documentation/Makefile
@@ -23,6 +23,7 @@ SPHINXOPTS    =
 SPHINXDIRS    = .
 DOCS_THEME    =
 DOCS_CSS      =
+RUSTDOC       =
 SPHINX_CONF   = conf.py
 PAPER         =
 BUILDDIR      = $(obj)/output
@@ -42,6 +43,10 @@ FONTS_CONF_DENY_VF ?= $(HOME)/deny-vf
 # User-friendly check for sphinx-build
 HAVE_SPHINX := $(shell if which $(SPHINXBUILD) >/dev/null 2>&1; then echo 1; else echo 0; fi)
 
+ifeq ($(CONFIG_RUST),y)
+	RUSTDOC="--rustdoc"
+endif
+
 ifeq ($(HAVE_SPHINX),0)
 
 .DEFAULT:
@@ -53,10 +58,10 @@ ifeq ($(HAVE_SPHINX),0)
 else # HAVE_SPHINX
 
 # Common documentation targets
-mandocs infodocs texinfodocs latexdocs epubdocs xmldocs pdfdocs linkcheckdocs:
+htmldocs mandocs infodocs texinfodocs latexdocs epubdocs xmldocs pdfdocs linkcheckdocs:
 	$(Q)@$(srctree)/tools/docs/sphinx-pre-install --version-check
-	+$(Q)$(PYTHON3) $(BUILD_WRAPPER) $@ \
-		--sphinxdirs="$(SPHINXDIRS)" --conf="$(SPHINX_CONF)" \
+	+$(Q)$(PYTHON3) $(BUILD_WRAPPER) $@ $(RUSTDOC)\
+		--sphinxdirs="$(SPHINXDIRS)" --conf="$(SPHINX_CONF)" $(RUSTDOC)\
 		--builddir="$(BUILDDIR)" --deny-vf=$(FONTS_CONF_DENY_VF) \
 		--theme=$(DOCS_THEME) --css=$(DOCS_CSS) --paper=$(PAPER)
 
@@ -67,24 +72,6 @@ pdfdocs:
 	@echo "  SKIP    Sphinx $@ target."
 endif
 
-# HTML main logic is identical to other targets. However, if rust is enabled,
-# an extra step at the end is required to generate rustdoc.
-htmldocs:
-	$(Q)@$(srctree)/tools/docs/sphinx-pre-install --version-check
-	+$(Q)$(PYTHON3) $(BUILD_WRAPPER) $@ \
-		--sphinxdirs="$(SPHINXDIRS)" --conf="$(SPHINX_CONF)" \
-		--builddir="$(BUILDDIR)" \
-		--theme=$(DOCS_THEME) --css=$(DOCS_CSS) --paper=$(PAPER)
-# If Rust support is available and .config exists, add rustdoc generated contents.
-# If there are any, the errors from this make rustdoc will be displayed but
-# won't stop the execution of htmldocs
-
-ifneq ($(wildcard $(srctree)/.config),)
-ifeq ($(CONFIG_RUST),y)
-	$(Q)$(MAKE) rustdoc || true
-endif
-endif
-
 endif # HAVE_SPHINX
 
 # The following targets are independent of HAVE_SPHINX, and the rules should
diff --git a/tools/docs/sphinx-build-wrapper b/tools/docs/sphinx-build-wrapper
index 7a6eb41837e6..e24486dede76 100755
--- a/tools/docs/sphinx-build-wrapper
+++ b/tools/docs/sphinx-build-wrapper
@@ -96,14 +96,6 @@ class SphinxBuilder:
     with the Kernel.
     """
 
-    def is_rust_enabled(self):
-        """Check if rust is enabled at .config"""
-        config_path = os.path.join(self.srctree, ".config")
-        if os.path.isfile(config_path):
-            with open(config_path, "r", encoding="utf-8") as f:
-                return "CONFIG_RUST=y" in f.read()
-        return False
-
     def get_path(self, path, use_cwd=False, abs_path=False):
         """
         Ancillary routine to handle patches the right way, as shell does.
@@ -218,8 +210,6 @@ class SphinxBuilder:
                                                       "scripts/kernel-doc.py"))
         self.builddir = self.get_path(builddir, use_cwd=True, abs_path=True)
 
-        self.config_rust = self.is_rust_enabled()
-
         #
         # Get directory locations for LaTeX build toolchain
         #
@@ -274,7 +264,7 @@ class SphinxBuilder:
 
             return subprocess.call(cmd, *args, **pwargs)
 
-    def handle_html(self, css, output_dir):
+    def handle_html(self, css, output_dir, rustdoc):
         """
         Extra steps for HTML and epub output.
 
@@ -282,20 +272,34 @@ class SphinxBuilder:
         copied to the output _static directory
         """
 
-        if not css:
-            return
+        if css:
+            css = os.path.expanduser(css)
+            if not css.startswith("/"):
+                css = os.path.join(self.srctree, css)
 
-        css = os.path.expanduser(css)
-        if not css.startswith("/"):
-            css = os.path.join(self.srctree, css)
+            static_dir = os.path.join(output_dir, "_static")
+            os.makedirs(static_dir, exist_ok=True)
 
-        static_dir = os.path.join(output_dir, "_static")
-        os.makedirs(static_dir, exist_ok=True)
+            try:
+                shutil.copy2(css, static_dir)
+            except (OSError, IOError) as e:
+                print(f"Warning: Failed to copy CSS: {e}", file=sys.stderr)
 
-        try:
-            shutil.copy2(css, static_dir)
-        except (OSError, IOError) as e:
-            print(f"Warning: Failed to copy CSS: {e}", file=sys.stderr)
+        if rustdoc:
+            if "MAKE" in self.env:
+                cmd = [self.env["MAKE"]]
+            else:
+                cmd = ["make", "LLVM=1"]
+
+            cmd += [ "rustdoc"]
+            if self.verbose:
+                print(" ".join(cmd))
+
+            try:
+                subprocess.run(cmd, check=True)
+            except subprocess.CalledProcessError as e:
+                print(f"Ignored errors when building rustdoc: {e}. Is RUST enabled?",
+                      file=sys.stderr)
 
     def build_pdf_file(self, latex_cmd, from_dir, path):
         """Builds a single pdf file using latex_cmd"""
@@ -576,7 +580,7 @@ class SphinxBuilder:
         shutil.rmtree(self.builddir, ignore_errors=True)
 
     def build(self, target, sphinxdirs=None, conf="conf.py",
-              theme=None, css=None, paper=None, deny_vf=None):
+              theme=None, css=None, paper=None, deny_vf=None, rustdoc=False):
         """
         Build documentation using Sphinx. This is the core function of this
         module. It prepares all arguments required by sphinx-build.
@@ -623,7 +627,7 @@ class SphinxBuilder:
 
             args.extend(["-D", f"latex_elements.papersize={paper}paper"])
 
-        if self.config_rust:
+        if rustdoc:
             args.extend(["-t", "rustdoc"])
 
         if conf:
@@ -699,7 +703,7 @@ class SphinxBuilder:
             # Ensure that each html/epub output will have needed static files
             #
             if target in ["htmldocs", "epubdocs"]:
-                self.handle_html(css, output_dir)
+                self.handle_html(css, output_dir, rustdoc)
 
         #
         # Step 2: Some targets (PDF and info) require an extra step once
@@ -756,6 +760,9 @@ def main():
     parser.add_argument('--deny-vf',
                         help="Configuration to deny variable fonts on pdf builds")
 
+    parser.add_argument('--rustdoc', action="store_true",
+                        help="Enable rustdoc build. Requires CONFIG_RUST")
+
     parser.add_argument("-v", "--verbose", action='store_true',
                         help="place build in verbose mode")
 
@@ -775,7 +782,7 @@ def main():
 
     builder.build(args.target, sphinxdirs=args.sphinxdirs, conf=args.conf,
                   theme=args.theme, css=args.css, paper=args.paper,
-                  deny_vf=args.deny_vf)
+                  rustdoc=args.rustdoc, deny_vf=args.deny_vf)
 
 if __name__ == "__main__":
     main()
-- 
2.51.0

[PATCH v8 23/24] tools/docs: sphinx-* break documentation bulds on openSUSE

[Mauro Carvalho Chehab]

Before this patch, building htmldocs on opensuseLEAP works
fine:

    # make htmldocs
    Available Python versions:
      /usr/bin/python3.11

    Python 3.6.15 not supported. Changing to /usr/bin/python3.11
    Python 3.6.15 not supported. Changing to /usr/bin/python3.11
    Using alabaster theme
    Using Python kernel-doc

    ...

As the logic detects that Python 3.6 is too old and recommends
intalling python311-Sphinx. If installed, documentation builds
work like a charm.

Yet, some develpers complained that running python3.11 instead
of python3 should not happen. So, let's break the build to make
them happier:

    $ make htmldocs
    Python 3.6.15 not supported. Bailing out
    You could run, instead:
      /usr/bin/python3.11 tools/docs/sphinx-build-wrapper htmldocs \
        --sphinxdirs=. --conf=conf.py --builddir=Documentation/output --theme= --css= \
        --paper=

    Python 3.6.15 not supported. Bailing out
    make[2]: *** [Documentation/Makefile:76: htmldocs] Error 1
    make[1]: *** [Makefile:1806: htmldocs] Error 2
    make: *** [Makefile:248: __sub-make] Error 2

It should be noticed that:

1. after this change, sphinx-pre-install needs to be called
   by hand:

    $ /usr/bin/python3.11 tools/docs/sphinx-pre-install
    Detected OS: openSUSE Leap 15.6.
    Sphinx version: 7.2.6

    All optional dependencies are met.
    Needed package dependencies are met.

2. sphinx-build-wrapper will auto-detect python3.11 and
   suggest a way to build the docs using the parameters passed
   via make variables. In this specific example:

   /usr/bin/python3.11 tools/docs/sphinx-build-wrapper htmldocs --sphinxdirs=. --conf=conf.py --theme= --css= --paper=

3. As this needs to be executed outside docs Makefile, it won't run
   the validation check scripts nor build Rust documentation if
   enabled, as the extra scripts are part of the docs Makefile.

Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
---
 tools/docs/lib/python_version.py | 28 ++++++++++++++++++++++++----
 tools/docs/sphinx-build-wrapper  |  3 ++-
 tools/docs/sphinx-pre-install    |  3 ++-
 3 files changed, 28 insertions(+), 6 deletions(-)

diff --git a/tools/docs/lib/python_version.py b/tools/docs/lib/python_version.py
index a9fda2470a26..4fde1b882164 100644
--- a/tools/docs/lib/python_version.py
+++ b/tools/docs/lib/python_version.py
@@ -20,9 +20,11 @@ Python version if present.
 import os
 import re
 import subprocess
+import shlex
 import sys
 
 from glob import glob
+from textwrap import indent
 
 class PythonVersion:
     """
@@ -44,6 +46,25 @@ class PythonVersion:
         """Returns a version tuple as major.minor.patch"""
         return ".".join([str(x) for x in version])
 
+    @staticmethod
+    def cmd_print(cmd, max_len=80):
+        cmd_line = []
+
+        for w in cmd:
+            w = shlex.quote(w)
+
+            if cmd_line:
+                if not max_len or len(cmd_line[-1]) + len(w) < max_len:
+                    cmd_line[-1] += " " + w
+                    continue
+                else:
+                    cmd_line[-1] += " \\"
+                    cmd_line.append(w)
+            else:
+                cmd_line.append(w)
+
+        return "\n  ".join(cmd_line)
+
     def __str__(self):
         """Returns a version tuple as major.minor.patch from self.version"""
         return self.ver_str(self.version)
@@ -130,14 +151,13 @@ class PythonVersion:
         else:
             new_python_cmd = None
 
-        if show_alternatives:
+        if show_alternatives and available_versions:
             print("You could run, instead:")
             for _, cmd in available_versions:
                 args = [cmd, script_path] + sys.argv[1:]
 
-                cmd_str = " ".join(args)
-                print(f"  {cmd_str}")
-            print()
+                cmd_str = indent(PythonVersion.cmd_print(args), "  ")
+                print(f"{cmd_str}\n")
 
         if bail_out:
             msg = f"Python {python_ver} not supported. Bailing out"
diff --git a/tools/docs/sphinx-build-wrapper b/tools/docs/sphinx-build-wrapper
index e24486dede76..103b0044bb0b 100755
--- a/tools/docs/sphinx-build-wrapper
+++ b/tools/docs/sphinx-build-wrapper
@@ -774,7 +774,8 @@ def main():
 
     args = parser.parse_args()
 
-    PythonVersion.check_python(MIN_PYTHON_VERSION)
+    PythonVersion.check_python(MIN_PYTHON_VERSION, show_alternatives=True,
+                               bail_out=True)
 
     builder = SphinxBuilder(builddir=args.builddir,
                             verbose=args.verbose, n_jobs=args.jobs,
diff --git a/tools/docs/sphinx-pre-install b/tools/docs/sphinx-pre-install
index 663d4e2a3f57..698989584b6a 100755
--- a/tools/docs/sphinx-pre-install
+++ b/tools/docs/sphinx-pre-install
@@ -1531,7 +1531,8 @@ def main():
 
     checker = SphinxDependencyChecker(args)
 
-    PythonVersion.check_python(MIN_PYTHON_VERSION)
+    PythonVersion.check_python(MIN_PYTHON_VERSION,
+                               bail_out=True, success_on_error=True)
     checker.check_needs()
 
 # Call main if not used as module
-- 
2.51.0