Merge tag 'docs-5.18-2' of git://git.lwn.net/linux

Pull more documentation updates from Jonathan Corbet:
 "Some late-arriving documentation improvements.

  This is mostly build-system fixes from Mauro and Akira; I also took
  the liberty of dropping in my 'messy diffstat' document"

* tag 'docs-5.18-2' of git://git.lwn.net/linux:
  docs: Add a document on how to fix a messy diffstat
  docs: sphinx/requirements: Limit jinja2<3.1
  Documentation: kunit: Fix cross-referencing warnings
  scripts/kernel-doc: change the line number meta info
  scripts/get_abi: change the file/line number meta info
  docs: kernel_include.py: add sphinx build dependencies
  docs: kernel_abi.py: add sphinx build dependencies
  docs: kernel_feat.py: add build dependencies
  scripts/get_feat.pl: allow output the parsed file names
  docs: kfigure.py: Don't warn of missing PDF converter in 'make htmldocs'
  Documentation: Fix duplicate statement about raw_spinlock_t type

10 files changed, 133 insertions, 21 deletions

diff --git a/Documentation/dev-tools/kunit/architecture.rst b/Documentation/dev-tools/kunit/architecture.rst
index aa2cea821e25..ff9c85a0bff2 100644
--- a/Documentation/dev-tools/kunit/architecture.rst
+++ b/Documentation/dev-tools/kunit/architecture.rst
@@ -26,10 +26,7 @@ The fundamental unit in KUnit is the test case. The KUnit test cases are
 grouped into KUnit suites. A KUnit test case is a function with type
 signature ``void (*)(struct kunit *test)``.
 These test case functions are wrapped in a struct called
-``struct kunit_case``. For code, see:
-
-.. kernel-doc:: include/kunit/test.h
-	:identifiers: kunit_case
+struct kunit_case.
 
 .. note:
 	``generate_params`` is optional for non-parameterized tests.
@@ -152,18 +149,12 @@ Parameterized Tests
 Each KUnit parameterized test is associated with a collection of
 parameters. The test is invoked multiple times, once for each parameter
 value and the parameter is stored in the ``param_value`` field.
-The test case includes a ``KUNIT_CASE_PARAM()`` macro that accepts a
+The test case includes a KUNIT_CASE_PARAM() macro that accepts a
 generator function.
 The generator function is passed the previous parameter and returns the next
 parameter. It also provides a macro to generate common-case generators based on
 arrays.
 
-For code, see:
-
-.. kernel-doc:: include/kunit/test.h
-	:identifiers: KUNIT_ARRAY_PARAM
-
-
 kunit_tool (Command Line Test Harness)
 ======================================
 
diff --git a/Documentation/locking/locktypes.rst b/Documentation/locking/locktypes.rst
index bfa75ea1b66a..9933faad4771 100644
--- a/Documentation/locking/locktypes.rst
+++ b/Documentation/locking/locktypes.rst
@@ -211,9 +211,6 @@ raw_spinlock_t and spinlock_t
 raw_spinlock_t
 --------------
 
-raw_spinlock_t is a strict spinning lock implementation regardless of the
-kernel configuration including PREEMPT_RT enabled kernels.
-
 raw_spinlock_t is a strict spinning lock implementation in all kernels,
 including PREEMPT_RT kernels.  Use raw_spinlock_t only in real critical
 core code, low-level interrupt handling and places where disabling
diff --git a/Documentation/maintainer/index.rst b/Documentation/maintainer/index.rst
index f0a60435b124..3e03283c144e 100644
--- a/Documentation/maintainer/index.rst
+++ b/Documentation/maintainer/index.rst
@@ -12,6 +12,7 @@ additions to this manual.
    configure-git
    rebasing-and-merging
    pull-requests
+   messy-diffstat
    maintainer-entry-profile
    modifying-patches
 
diff --git a/Documentation/maintainer/messy-diffstat.rst b/Documentation/maintainer/messy-diffstat.rst
new file mode 100644
index 000000000000..c015f66d7621
--- /dev/null
+++ b/Documentation/maintainer/messy-diffstat.rst
@@ -0,0 +1,96 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+=====================================
+Handling messy pull-request diffstats
+=====================================
+
+Subsystem maintainers routinely use ``git request-pull`` as part of the
+process of sending work upstream.  Normally, the result includes a nice
+diffstat that shows which files will be touched and how much of each will
+be changed.  Occasionally, though, a repository with a relatively
+complicated development history will yield a massive diffstat containing a
+great deal of unrelated work.  The result looks ugly and obscures what the
+pull request is actually doing.  This document describes what is happening
+and how to fix things up; it is derived from The Wisdom of Linus Torvalds,
+found in Linus1_ and Linus2_.
+
+.. _Linus1: https://lore.kernel.org/lkml/CAHk-=wg3wXH2JNxkQi+eLZkpuxqV+wPiHhw_Jf7ViH33Sw7PHA@mail.gmail.com/
+.. _Linus2: https://lore.kernel.org/lkml/CAHk-=wgXbSa8yq8Dht8at+gxb_idnJ7X5qWZQWRBN4_CUPr=eQ@mail.gmail.com/
+
+A Git development history proceeds as a series of commits.  In a simplified
+manner, mainline kernel development looks like this::
+
+  ... vM --- vN-rc1 --- vN-rc2 --- vN-rc3 --- ... --- vN-rc7 --- vN
+
+If one wants to see what has changed between two points, a command like
+this will do the job::
+
+  $ git diff --stat --summary vN-rc2..vN-rc3
+
+Here, there are two clear points in the history; Git will essentially
+"subtract" the beginning point from the end point and display the resulting
+differences.  The requested operation is unambiguous and easy enough to
+understand.
+
+When a subsystem maintainer creates a branch and commits changes to it, the
+result in the simplest case is a history that looks like::
+
+  ... vM --- vN-rc1 --- vN-rc2 --- vN-rc3 --- ... --- vN-rc7 --- vN
+                          |
+                          +-- c1 --- c2 --- ... --- cN
+
+If that maintainer now uses ``git diff`` to see what has changed between
+the mainline branch (let's call it "linus") and cN, there are still two
+clear endpoints, and the result is as expected.  So a pull request
+generated with ``git request-pull`` will also be as expected.  But now
+consider a slightly more complex development history::
+
+  ... vM --- vN-rc1 --- vN-rc2 --- vN-rc3 --- ... --- vN-rc7 --- vN
+                |         |
+                |         +-- c1 --- c2 --- ... --- cN
+                |                   /
+                +-- x1 --- x2 --- x3
+
+Our maintainer has created one branch at vN-rc1 and another at vN-rc2; the
+two were then subsequently merged into c2.  Now a pull request generated
+for cN may end up being messy indeed, and developers often end up wondering
+why.
+
+What is happening here is that there are no longer two clear end points for
+the ``git diff`` operation to use.  The development culminating in cN
+started in two different places; to generate the diffstat, ``git diff``
+ends up having pick one of them and hoping for the best.  If the diffstat
+starts at vN-rc1, it may end up including all of the changes between there
+and the second origin end point (vN-rc2), which is certainly not what our
+maintainer had in mind.  With all of that extra junk in the diffstat, it
+may be impossible to tell what actually happened in the changes leading up
+to cN.
+
+Maintainers often try to resolve this problem by, for example, rebasing the
+branch or performing another merge with the linus branch, then recreating
+the pull request.  This approach tends not to lead to joy at the receiving
+end of that pull request; rebasing and/or merging just before pushing
+upstream is a well-known way to get a grumpy response.
+
+So what is to be done?  The best response when confronted with this
+situation is to indeed to do a merge with the branch you intend your work
+to be pulled into, but to do it privately, as if it were the source of
+shame.  Create a new, throwaway branch and do the merge there::
+
+  ... vM --- vN-rc1 --- vN-rc2 --- vN-rc3 --- ... --- vN-rc7 --- vN
+                |         |                                      |
+                |         +-- c1 --- c2 --- ... --- cN           |
+                |                   /               |            |
+                +-- x1 --- x2 --- x3                +------------+-- TEMP
+
+The merge operation resolves all of the complications resulting from the
+multiple beginning points, yielding a coherent result that contains only
+the differences from the mainline branch.  Now it will be possible to
+generate a diffstat with the desired information::
+
+  $ git diff -C --stat --summary linus..TEMP
+
+Save the output from this command, then simply delete the TEMP branch;
+definitely do not expose it to the outside world.  Take the saved diffstat
+output and edit it into the messy pull request, yielding a result that
+shows what is really going on.  That request can then be sent upstream.
diff --git a/Documentation/sphinx/kernel_abi.py b/Documentation/sphinx/kernel_abi.py
index 4392b3cb4020..b5feb5b1d905 100644
--- a/Documentation/sphinx/kernel_abi.py
+++ b/Documentation/sphinx/kernel_abi.py
@@ -128,6 +128,7 @@ class KernelCmd(Directive):
         return out
 
     def nestedParse(self, lines, fname):
+        env = self.state.document.settings.env
         content = ViewList()
         node = nodes.section()
 
@@ -137,7 +138,7 @@ class KernelCmd(Directive):
                 code_block += "\n    " + l
             lines = code_block + "\n\n"
 
-        line_regex = re.compile("^#define LINENO (\S+)\#([0-9]+)$")
+        line_regex = re.compile("^\.\. LINENO (\S+)\#([0-9]+)$")
         ln = 0
         n = 0
         f = fname
@@ -154,6 +155,9 @@ class KernelCmd(Directive):
                     self.do_parse(content, node)
                     content = ViewList()
 
+                    # Add the file to Sphinx build dependencies
+                    env.note_dependency(os.path.abspath(f))
+
                 f = new_f
 
                 # sphinx counts lines from 0
diff --git a/Documentation/sphinx/kernel_feat.py b/Documentation/sphinx/kernel_feat.py
index 8138d69a6987..27b701ed3681 100644
--- a/Documentation/sphinx/kernel_feat.py
+++ b/Documentation/sphinx/kernel_feat.py
@@ -33,6 +33,7 @@ u"""
 
 import codecs
 import os
+import re
 import subprocess
 import sys
 
@@ -82,7 +83,7 @@ class KernelFeat(Directive):
 
         env = doc.settings.env
         cwd = path.dirname(doc.current_source)
-        cmd = "get_feat.pl rest --dir "
+        cmd = "get_feat.pl rest --enable-fname --dir "
         cmd += self.arguments[0]
 
         if len(self.arguments) > 1:
@@ -102,7 +103,22 @@ class KernelFeat(Directive):
         shell_env["srctree"] = srctree
 
         lines = self.runCmd(cmd, shell=True, cwd=cwd, env=shell_env)
-        nodeList = self.nestedParse(lines, fname)
+
+        line_regex = re.compile("^\.\. FILE (\S+)$")
+
+        out_lines = ""
+
+        for line in lines.split("\n"):
+            match = line_regex.search(line)
+            if match:
+                fname = match.group(1)
+
+                # Add the file to Sphinx build dependencies
+                env.note_dependency(os.path.abspath(fname))
+            else:
+                out_lines += line + "\n"
+
+        nodeList = self.nestedParse(out_lines, fname)
         return nodeList
 
     def runCmd(self, cmd, **kwargs):
diff --git a/Documentation/sphinx/kernel_include.py b/Documentation/sphinx/kernel_include.py
index f523aa68a36b..abe768088377 100755
--- a/Documentation/sphinx/kernel_include.py
+++ b/Documentation/sphinx/kernel_include.py
@@ -59,6 +59,7 @@ class KernelInclude(Include):
     u"""KernelInclude (``kernel-include``) directive"""
 
     def run(self):
+        env = self.state.document.settings.env
         path = os.path.realpath(
             os.path.expandvars(self.arguments[0]))
 
@@ -70,6 +71,8 @@ class KernelInclude(Include):
 
         self.arguments[0] = path
 
+        env.note_dependency(os.path.abspath(path))
+
         #return super(KernelInclude, self).run() # won't work, see HINTs in _run()
         return self._run()
 
diff --git a/Documentation/sphinx/kerneldoc.py b/Documentation/sphinx/kerneldoc.py
index 8189c33b9dda..9395892c7ba3 100644
--- a/Documentation/sphinx/kerneldoc.py
+++ b/Documentation/sphinx/kerneldoc.py
@@ -130,7 +130,7 @@ class KernelDocDirective(Directive):
             result = ViewList()
 
             lineoffset = 0;
-            line_regex = re.compile("^#define LINENO ([0-9]+)$")
+            line_regex = re.compile("^\.\. LINENO ([0-9]+)$")
             for line in lines:
                 match = line_regex.search(line)
                 if match:
diff --git a/Documentation/sphinx/kfigure.py b/Documentation/sphinx/kfigure.py
index 24d2b2addcce..cefdbb7e7523 100644
--- a/Documentation/sphinx/kfigure.py
+++ b/Documentation/sphinx/kfigure.py
@@ -212,7 +212,7 @@ def setupTools(app):
         if convert_cmd:
             kernellog.verbose(app, "use convert(1) from: " + convert_cmd)
         else:
-            kernellog.warn(app,
+            kernellog.verbose(app,
                 "Neither inkscape(1) nor convert(1) found.\n"
                 "For SVG to PDF conversion, "
                 "install either Inkscape (https://inkscape.org/) (preferred) or\n"
@@ -296,8 +296,10 @@ def convert_image(img_node, translator, src_fname=None):
 
         if translator.builder.format == 'latex':
             if not inkscape_cmd and convert_cmd is None:
-                kernellog.verbose(app,
-                                  "no SVG to PDF conversion available / include SVG raw.")
+                kernellog.warn(app,
+                                  "no SVG to PDF conversion available / include SVG raw."
+                                  "\nIncluding large raw SVGs can cause xelatex error."
+                                  "\nInstall Inkscape (preferred) or ImageMagick.")
                 img_node.replace_self(file2literal(src_fname))
             else:
                 dst_fname = path.join(translator.builder.outdir, fname + '.pdf')
diff --git a/Documentation/sphinx/requirements.txt b/Documentation/sphinx/requirements.txt
index 9a35f50798a6..2c573541ab71 100644
--- a/Documentation/sphinx/requirements.txt
+++ b/Documentation/sphinx/requirements.txt
@@ -1,2 +1,4 @@
+# jinja2>=3.1 is not compatible with Sphinx<4.0
+jinja2<3.1
 sphinx_rtd_theme
 Sphinx==2.4.4