linux.git
12 months agodocs: verify/bisect: drop 'v' prefix, EOL aspect, and assorted fixes
Thorsten Leemhuis [Mon, 18 Mar 2024 08:38:38 +0000 (09:38 +0100)]
docs: verify/bisect: drop 'v' prefix, EOL aspect, and assorted fixes

A bunch of minor fixes and improvements and two other things:

- Explain the 'v' version prefix when it's first used, but drop it
  everywhere in the text for consistency. Also drop single quotes around
  a few version numbers.

- Point out that testing a stable/longterm kernel only makes sense if
  the series is still supported.

Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <f13d203d5975419608996300992eaa2e4fcc2dc1.1710750972.git.linux@leemhuis.info>

12 months agodocs: verify/bisect: check taint flag
Thorsten Leemhuis [Mon, 18 Mar 2024 08:38:37 +0000 (09:38 +0100)]
docs: verify/bisect: check taint flag

Instruct readers to check the taint flag, as the reason why it's set
might directly or indirectly cause the bug or interfere with testing.

Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <8fcaffa8e85f36d51178d61061355c3c8bc85a0f.1710750972.git.linux@leemhuis.info>

12 months agodocs: verify/bisect: improve install instructions
Thorsten Leemhuis [Mon, 18 Mar 2024 08:38:36 +0000 (09:38 +0100)]
docs: verify/bisect: improve install instructions

These changes among others ensure modules will be installed when
/sbin/installkernel is missing. Furthermore describe better what tasks
the script ideally performs so that users can more easily check if those
have been taken care of. In addition to that point to the distro's
documentation for further details on installing kernels manually.

Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <e392bd5eb12654bed635f32b24304a712b0c67d1.1710750972.git.linux@leemhuis.info>

12 months agodocs: handling-regressions.rst: Update regzbot command fixed-by to fix
Nícolas F. R. A. Prado [Mon, 11 Mar 2024 14:36:16 +0000 (10:36 -0400)]
docs: handling-regressions.rst: Update regzbot command fixed-by to fix

On the reference documentation for regzbot, the fixed-by command has
been renamed to fix. Update the kernel documentation accordingly.

Link: https://gitlab.com/knurd42/regzbot/-/blob/main/docs/reference.md
Link: https://gitlab.com/knurd42/regzbot/-/commit/6d8d30f6bda84e1b711121bb98a07a464d3f089a
Reviewed-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: "Nícolas F. R. A. Prado" <nfraprado@collabora.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20240311-regzbot-fixes-v2-2-98c1b6ec0678@collabora.com>

12 months agodocs: *-regressions.rst: Add colon to regzbot commands
Nícolas F. R. A. Prado [Mon, 11 Mar 2024 14:36:15 +0000 (10:36 -0400)]
docs: *-regressions.rst: Add colon to regzbot commands

Use colon as command terminator everywhere for consistency, even though
it's not strictly necessary. That way it will also match regzbot's
reference documentation.

Link: https://gitlab.com/knurd42/regzbot/-/blob/main/docs/reference.md
Reviewed-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: "Nícolas F. R. A. Prado" <nfraprado@collabora.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20240311-regzbot-fixes-v2-1-98c1b6ec0678@collabora.com>

12 months agodoc: Fix typo in admin-guide/cifs/introduction.rst
Kendra Moore [Tue, 12 Mar 2024 08:47:53 +0000 (04:47 -0400)]
doc: Fix typo in admin-guide/cifs/introduction.rst

This patch corrects a spelling error specifically
the word "supports" was misspelled "suppors".

No functional changes are made by this patch; it
only improves the accuracy and readability of the
documentation.

Signed-off-by: Kendra Moore <kendra.j.moore3443@gmail.com>
Reviewed-by: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20240312084753.27122-1-kendra.j.moore3443@gmail.com>

12 months agoREADME: Fix spelling
Maki Hatano [Wed, 13 Mar 2024 10:01:07 +0000 (18:01 +0800)]
README: Fix spelling

- ReStructured Text should be exactly reStructuredText
- "reStructuredText" is ONE word, not two! according to https://docutils.sourceforge.io/rst.html

Signed-off-by: Maki Hatano <Maki.Y.Hatano@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20240313100136.20424-1-Maki.Y.Hatano@gmail.com>

13 months agodocs: verify/bisect: fixes, finetuning, and support for Arch
Thorsten Leemhuis [Wed, 6 Mar 2024 09:21:12 +0000 (10:21 +0100)]
docs: verify/bisect: fixes, finetuning, and support for Arch

Assorted changes for the recently added document.

Improvements:

* Add instructions for installing required software on Arch Linux.

Fixes:

* Move a 'git remote add -t master stable [...]' from a totally wrong
  to the right place.

* Fix two anchors.

* Add two required packages to the openSUSE install instructions.

Fine tuning:

* Improve the reference section about downloading Linux mainline sources
  to make it more obvious that those are alternatives.

* Include the full instructions for git bundles to ensure the remote
  gets the right name; that way the text also works stand alone.

* Install ncurses and qt headers for use of menuconfig and xconfig by
  default, but tell users that they are free to omit them.

* Mention ahead of time which version number are meant as example in
  commands used during the step-by-step guide.

* Mention that 'kernel-install remove' might do a incomplete job.

Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <6592c9ef4244faa484b4113f088dbc1beca61015.1709716794.git.linux@leemhuis.info>

13 months agodocs: Makefile: Add dependency to $(YNL_INDEX) for targets other than htmldocs
Akira Yokosawa [Tue, 5 Mar 2024 04:23:00 +0000 (13:23 +0900)]
docs: Makefile: Add dependency to $(YNL_INDEX) for targets other than htmldocs

Commit f061c9f7d058 ("Documentation: Document each netlink family")
added recipes for YAML -> RST conversion.
Then commit 7da8bdbf8f5d ("docs: Makefile: Fix make cleandocs by
deleting generated .rst files") made sure those converted .rst files
are cleaned by "make cleandocs".

However, they took care of htmldocs build only.

If one of other targets such as latexdocs or epubdocs is built
without building htmldocs, missing .rst files can cause additional
WARNINGs from sphinx-build as follow:

    ./Documentation/userspace-api/netlink/specs.rst:18: WARNING: undefined label: 'specs'
    ./Documentation/userspace-api/netlink/netlink-raw.rst:64: WARNING: unknown document: '../../networking/netlink_spec/rt_link'
    ./Documentation/userspace-api/netlink/netlink-raw.rst:64: WARNING: unknown document: '../../networking/netlink_spec/tc'
    ./Documentation/userspace-api/netlink/index.rst:21: WARNING: undefined label: 'specs'

Add dependency to $(YNL_INDEX) for other targets and allow any targets
to be built cleanly right after "make cleandocs".

Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Cc: stable@vger.kernel.org # v6.7
Cc: Thorsten Blum <thorsten.blum@toblux.com>
Cc: Breno Leitao <leitao@debian.org>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Reviwed-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <e876e3c8-109d-4bc8-9916-05a4bc4ee9ac@gmail.com>

13 months agodocs: Move ja_JP/howto.rst to ja_JP/process/howto.rst
Akira Yokosawa [Thu, 29 Feb 2024 09:34:42 +0000 (18:34 +0900)]
docs: Move ja_JP/howto.rst to ja_JP/process/howto.rst

Let Japanese translation of howto.rst in the language drop-down list
by moving it to the expected place.

Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Cc: Tsugikazu Shibata <shibata@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <b175c52f-34ee-4753-b172-e57fee6fcc30@gmail.com>

13 months agodocs: submit-checklist: use subheadings
Lukas Bulwahn [Thu, 29 Feb 2024 03:07:42 +0000 (04:07 +0100)]
docs: submit-checklist: use subheadings

During review (see Link), Jani Nikula suggested to use proper subheadings
instead of using italics to indicate the different new top-level
categories in the checklist. Further the top heading should follow the
common scheme.

Use subheadings. Adjust to common heading adornment.

Link: https://lore.kernel.org/linux-doc/87o7c3mlwb.fsf@intel.com/
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20240229030743.9125-3-lukas.bulwahn@gmail.com>

13 months agodocs: submit-checklist: structure by category
Lukas Bulwahn [Thu, 29 Feb 2024 03:07:41 +0000 (04:07 +0100)]
docs: submit-checklist: structure by category

While going through the submit checklist, the list order seemed rather
random, probably just by historical coincidences of always adding yet the
next point someone thought of at the end of the list.

Structure and order them by the category of such activity,
reviewing, documenting, checking with tools, building and testing.

As the diff of the reordering is large:
Review code now includes previous points 1, 5 and 22.
Review Kconfig includes previous 6, 7 and 8.
Documenting includes previous 11, 15, 16, 17, 18 and 23.
Checking with tools includes previous 5, 9 and 10.
Building includes previous 2, 3, 20 and 24.
Testing includes previous 12, 13, 14, 19 and 21.

Previous point 4 (compile for ppc64) was merged into point 3 (build for
many architectures), as it was just a further note to cross-compiling.

Previous point 5 was split into one in review and one in checking
to have every previous point in the right category.
Point 11 was shortened, as building documentation is mentioned already
in Build your code, 1d.

A note that was presented visually much too aggressive in the HTML view was
turned into a simple "Note that..." sentence in the enumeration.

The recommendation to test with the -mm patchset (previous 21, now
testing, point 5) was updated to the current state of affairs to test with
a recent tag of linux-next.

Note that the previous first point still remains the first list even after
reordering. Randy confirmed that it was important to Stephen Rothwell to
keep 'include what you use' to be the first in the list.

While at it, replace the reference to the obsolete CONFIG_DEBUG_SLAB with
CONFIG_SLUB_DEBUG.

Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20240229030743.9125-2-lukas.bulwahn@gmail.com>

13 months agodocs: new text on bisecting which also covers bug validation
Thorsten Leemhuis [Fri, 1 Mar 2024 08:41:06 +0000 (09:41 +0100)]
docs: new text on bisecting which also covers bug validation

Add a second document on bisecting regressions explaining the whole
process from beginning to end -- while also describing how to validate
if a problem is still present in mainline.  This "two in one" approach
is possible, as checking whenever a bug is in mainline is one of the
first steps before performing a bisection anyway and thus needs to be
described. Due to this approach the text also works quite nicely in
conjunction with Documentation/admin-guide/reporting-issues.rst, as it
covers all typical cases where users will need to build a kernel in
exactly the same order.

The text targets users that normally run kernels from their Linux
distributor who might never have compiled their own kernel.

This aim is why the first kernel built while following this guide is
generated from the latest mainline codebase. This will rule out that the
regression (a) was fixed already and (b) is caused by config change a
vendor distributor performed; checking mainline will furthermore (c)
determine if the issue is something that needs to be reported to the
regular developers or the stable team (this is needed even when readers
bisect within a stable series).

Only then are readers instructed to build their own variant of the
'good' kernel to validate the trimmed .config file created during early
in the guide, as performing a bisection with a broken one would be a
waste of time. There is a small downside of this order: readers might
have to go back to testing mainline, if it turns out there is a problem
with their .config. But that should be rare -- and if the regression was
already fixed readers might not get to this point anyway. Hence in the
end this order should mean that readers built less kernels overall.

This sequence allows the text to easily cover the "check if a bug is
present in the upstream kernel" case while only making things a tiny bit
more complicated.

The text tries to prevent readers from running into many mistakes users
are known to frequently make. The steps required for this might look
superfluous for people that are already familiar with bisections -- but
anyone with that knowledge should be able to adapt the instructions to
their use-case or will not need this text at all.

Style and structure of the text match the one
Documentation/admin-guide/quickly-build-trimmed-linux.rst uses. Quite a
few paragraphs are even copied from there and not changed at all or only
slightly. This will complicate maintenance, as some future changes to
one of these documents will have to be replicated in the other. But this
is the lesser evil: solutions like "sending readers from one document
over to the other" or "extracting the common parts into a separate
document" might work in other cases, but would be too confusing here
given the topic and the target audience.

Signed-off-by: Thorsten Leemhuis <linux@leemhuis.info>
[jc: Undo spurious removal of subsection header line]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <02b084a06de4ad61ac4ecd92b9265d4df4d03d71.1709282441.git.linux@leemhuis.info>

13 months agodocs: drop the version constraints for sphinx and dependencies
Lukas Bulwahn [Fri, 1 Mar 2024 14:18:00 +0000 (15:18 +0100)]
docs: drop the version constraints for sphinx and dependencies

As discussed (see Links), there is some inertia to move to the recent
Sphinx versions for the doc build environment.

As first step, drop the version constraints and the related comments. As
sphinx depends on jinja2, jinja2 is pulled in automatically. So drop that.
Then, the sphinx-pre-install script will fail though with:

  Can't get default sphinx version from ./Documentation/sphinx/requirements.txt at ./scripts/sphinx-pre-install line 305.

The script simply expects to parse a version constraint with Sphinx in the
requirements.txt. That version is used in the script for suggesting the
virtualenv directory name.

To suggest a virtualenv directory name, when there is no version given in
the requirements.txt, one could try to guess the version that would be
downloaded with 'pip install -r Documentation/sphinx/requirements.txt'.
However, there seems no simple way to get that version without actually
setting up the venv and running pip. So, instead, name the directory with
the fixed name 'sphinx_latest'.

Finally update the Sphinx build documentation to reflect this directory
name change.

Link: https://lore.kernel.org/linux-doc/874jf4m384.fsf@meer.lwn.net/
Link: https://lore.kernel.org/linux-doc/20240226093854.47830-1-lukas.bulwahn@gmail.com/
Reviewed-by: Akira Yokosawa <akiyks@gmail.com>
Tested-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20240301141800.30218-1-lukas.bulwahn@gmail.com>

13 months agodocs: kerneldoc-preamble.sty: Remove code for Sphinx <2.4
Akira Yokosawa [Fri, 1 Mar 2024 14:41:22 +0000 (23:41 +0900)]
docs: kerneldoc-preamble.sty: Remove code for Sphinx <2.4

Now that Sphinx 2.4.4 or better is required, get rid of
\providecommand{}'s for compatibility with Sphinx 1.7.9.

While at it, reword the comment on \sphinxtableofcontentshook
for better description of why it needs to be emptied.

Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <ed1ec6f2-0050-46f6-807d-8679f26427e9@gmail.com>

13 months agodocs: Restore "smart quotes" for quotes
Akira Yokosawa [Sun, 25 Feb 2024 09:46:00 +0000 (18:46 +0900)]
docs: Restore "smart quotes" for quotes

Commit eaae75754d81 ("docs: turn off "smart quotes" in the HTML build")
disabled conversion of quote marks along with that of dashes.
Despite the short summary, the change affects not only HTML build
but also other build targets including PDF.

However, as "smart quotes" had been enabled for more than half a
decade already, quite a few readers of HTML pages are likely expecting
conversions of "foo" -> “foo” and 'bar' -> ‘bar’.

Furthermore, in LaTeX typesetting convention, it is common to use
distinct marks for opening and closing quote marks.

To satisfy such readers' expectation, restore conversion of quotes
only by setting smartquotes_action [1].

Link: [1] https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-smartquotes_action
Cc: stable@vger.kernel.org # v6.4
Signed-off-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240225094600.65628-1-akiyks@gmail.com
13 months agodocs/zh_CN: accurate translation of "function"
Lu Dai [Thu, 25 Jan 2024 20:05:50 +0000 (20:05 +0000)]
docs/zh_CN: accurate translation of "function"

Choose an accurate translation based on the context.

Signed-off-by: Lu Dai <dai.lu@exordes.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240125200549.7192-1-dai.lu@exordes.com
13 months agoMerge branch 'docs-fixes' into docs-mw
Jonathan Corbet [Wed, 21 Feb 2024 20:46:25 +0000 (13:46 -0700)]
Merge branch 'docs-fixes' into docs-mw

Bring in the build fixes so that we can successfully build PDFs again.

13 months agodocs: Include simplified link titles in main index
Carlos Bilbao [Tue, 9 Jan 2024 15:56:43 +0000 (09:56 -0600)]
docs: Include simplified link titles in main index

Include simplified link titles in the main page's documentation index to
enhance website's readability and UX. Update the text that directs users to
various documents without changing the actual titles chosen by the authors.

Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240109155643.3489369-3-carlos.bilbao@amd.com
13 months agodocs: Correct formatting of title in admin-guide/index.rst
Carlos Bilbao [Tue, 9 Jan 2024 15:56:42 +0000 (09:56 -0600)]
docs: Correct formatting of title in admin-guide/index.rst

Adjust the title of "The Linux kernel user's and administrator's guide" to
adhere to the expected reStructuredText (rst) formatting, using double
equal signs for the main header.

Signed-off-by: Carlos Bilbao <carlos.bilbao@amd.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240109155643.3489369-2-carlos.bilbao@amd.com
13 months agodocs: kernel_feat.py: fix build error for missing files
Vegard Nossum [Mon, 5 Feb 2024 17:51:26 +0000 (18:51 +0100)]
docs: kernel_feat.py: fix build error for missing files

If the directory passed to the '.. kernel-feat::' directive does not
exist or the get_feat.pl script does not find any files to extract
features from, Sphinx will report the following error:

    Sphinx parallel build error:
    UnboundLocalError: local variable 'fname' referenced before assignment
    make[2]: *** [Documentation/Makefile:102: htmldocs] Error 2

This is due to how I changed the script in c48a7c44a1d0 ("docs:
kernel_feat.py: fix potential command injection"). Before that, the
filename passed along to self.nestedParse() in this case was weirdly
just the whole get_feat.pl invocation.

We can fix it by doing what kernel_abi.py does -- just pass
self.arguments[0] as 'fname'.

Fixes: c48a7c44a1d0 ("docs: kernel_feat.py: fix potential command injection")
Cc: Justin Forbes <jforbes@fedoraproject.org>
Cc: Salvatore Bonaccorso <carnil@debian.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Link: https://lore.kernel.org/r/20240205175133.774271-2-vegard.nossum@oracle.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
13 months agoMAINTAINERS: Set the field name for subsystem profile section
SeongJae Park [Fri, 16 Feb 2024 20:19:02 +0000 (12:19 -0800)]
MAINTAINERS: Set the field name for subsystem profile section

Subsystem profile section entry identifier is not having its field name
that can be parsed by maintainers_include.py, unlike other sections
which have their own human-readable field names.  As a result, profile
sections on rendered rst file is having weird name, 'P:'.  Set the field
name as 'Subsystem Profile'.

Fixes: 4699c504e603 ("Maintainer Handbook: Maintainer Entry Profile")
Signed-off-by: SeongJae Park <sj@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240216201902.10095-1-sj@kernel.org
13 months agokasan: Add documentation for CONFIG_KASAN_EXTRA_INFO
Juntong Deng [Thu, 15 Feb 2024 19:17:23 +0000 (19:17 +0000)]
kasan: Add documentation for CONFIG_KASAN_EXTRA_INFO

This patch adds CONFIG_KASAN_EXTRA_INFO introduction information to
KASAN documentation.

Signed-off-by: Juntong Deng <juntong.deng@outlook.com>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Link: https://lore.kernel.org/r/AM6PR03MB5848C52B871DA67455F0B2F2994D2@AM6PR03MB5848.eurprd03.prod.outlook.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
13 months agoFixed case issue with 'fault-injection' in documentation
Ran.Park [Wed, 14 Feb 2024 11:40:08 +0000 (19:40 +0800)]
Fixed case issue with 'fault-injection' in documentation

In the 'fault-injection' subdirectory, the first letter F
is capitalized, whereas in index.rst f is lowercase, but in
index.rst all other elements in the same column are capitalized.

Signed-off-by: "Ran.Park" <ranpark@foxmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/tencent_3EA07E65C43816C2A8402DC655CF98916B06@qq.com
13 months agokernel-doc: handle #if in enums as well
Johannes Berg [Wed, 14 Feb 2024 13:29:38 +0000 (14:29 +0100)]
kernel-doc: handle #if in enums as well

In addition to #ifdef, #define and #endif, also handle
any #if since we may be using e.g. #if IS_ENABLED(...).

I didn't find any instances of this in the kernel now,
there are enums with such ifs inside, but I didn't find
any with kernel-doc as well. However, it came up as we
were adding such a construct in our driver and warnings
from kernel-doc were the result.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240214142937.80ee86a3beae.Ibcc5bd97a20cd10a792663e4b254cd46c7e8b520@changeid
13 months agoDocumentation: update mailing list addresses
Konstantin Ryabitsev [Wed, 14 Feb 2024 20:09:53 +0000 (15:09 -0500)]
Documentation: update mailing list addresses

The mailman2 server running on lists.linuxfoundation.org will be shut
down in very imminent future. Update all instances of obsolete list
addresses throughout the tree with their new destinations.

Signed-off-by: Konstantin Ryabitsev <konstantin@linuxfoundation.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240214-lf-org-list-migration-v1-1-ef1eab4b1543@linuxfoundation.org
13 months agodoc: kerneldoc.py: fix indentation
Vegard Nossum [Thu, 15 Feb 2024 13:48:28 +0000 (14:48 +0100)]
doc: kerneldoc.py: fix indentation

kerneldoc.py is mostly indented with 4 spaces (like PEP8 suggests);
replace the last remaining tabs for consistency.

No functional change.

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240215134828.1277109-6-vegard.nossum@oracle.com
13 months agoscripts/kernel-doc: simplify signature printing
Vegard Nossum [Thu, 15 Feb 2024 13:48:27 +0000 (14:48 +0100)]
scripts/kernel-doc: simplify signature printing

Untangle some of the $is_macro logic and the nested conditionals.

This makes it easier to see where and how the signature is actually
printed.

No functional change.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240215134828.1277109-5-vegard.nossum@oracle.com
13 months agoscripts/kernel-doc: separate out function signature
Vegard Nossum [Thu, 15 Feb 2024 13:48:26 +0000 (14:48 +0100)]
scripts/kernel-doc: separate out function signature

Format the entire function signature and place it in a separate variable;
this both makes it easier to understand what these lines of code are doing
and will allow us to simplify the code further in the following patch.

No functional change.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240215134828.1277109-4-vegard.nossum@oracle.com
13 months agoscripts/kernel-doc: simplify function printing
Vegard Nossum [Thu, 15 Feb 2024 13:48:25 +0000 (14:48 +0100)]
scripts/kernel-doc: simplify function printing

Get rid of the $start variable, since it's really not necessary.

No functional change.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240215134828.1277109-3-vegard.nossum@oracle.com
13 months agoscripts/kernel-doc: add modeline for vim users
Vegard Nossum [Thu, 15 Feb 2024 13:48:24 +0000 (14:48 +0100)]
scripts/kernel-doc: add modeline for vim users

Set 'softtabstop' to 4 spaces, which will hopefully help keep the
indentation in this file consistent going forwards.

This mirrors the modeline in scripts such as recordmcount.pl, ktest.pl,
and others.

Emacs seems to use 4 spaces to indent by default, so it doesn't require
anything special here.

No functional change.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240215134828.1277109-2-vegard.nossum@oracle.com
13 months agodocs: translations: use attribute to store current language
Vegard Nossum [Thu, 15 Feb 2024 06:41:09 +0000 (07:41 +0100)]
docs: translations: use attribute to store current language

Akira Yokosawa reported [1] that the "translations" extension we added in
commit 7418ec5b151f ("docs: translations: add translations links when they
exist") broke the build on Sphinx versions v6.1.3 through 7.1.2 (possibly
others) with the following error:

    Exception occurred:
      File "/usr/lib/python3.12/site-packages/sphinx/util/nodes.py", line 624, in _copy_except__document
        newnode = self.__class__(rawsource=self.rawsource, **self.attributes)
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
    TypeError: LanguagesNode.__init__() missing 1 required positional argument: 'current_language'
    The full traceback has been saved in /tmp/sphinx-err-7xmwytuu.log, if you want to report the issue to the developers.

Solve this problem by making 'current_language' a true element attribute
of the LanguagesNode element, which is probably the more correct way to do
it anyway.

Tested on Sphinx 2.x, 3.x, 6.x, and 7.x.

[1]: https://lore.kernel.org/all/54a56c2e-a27c-45a0-b712-02a7bc7d2673@gmail.com/

Fixes: 7418ec5b151f ("docs: translations: add translations links when they exist")
Reported-by: Akira Yokosawa <akiyks@gmail.com>
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Closes: https://lore.kernel.org/all/54a56c2e-a27c-45a0-b712-02a7bc7d2673@gmail.com/
Tested-by: Akira Yokosawa <akiyks@gmail.com> # Sphinx 4.3.2, 5.3.0 and 6.2.1
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240215064109.1193556-1-vegard.nossum@oracle.com
13 months agodocs: Instruct LaTeX to cope with deeper nesting
Jonathan Corbet [Mon, 19 Feb 2024 16:05:38 +0000 (09:05 -0700)]
docs: Instruct LaTeX to cope with deeper nesting

The addition of the XFS online fsck documentation starting with
commit a8f6c2e54ddc ("xfs: document the motivation for online fsck design")
added a deeper level of nesting than LaTeX is prepared to deal with.  That
caused a pdfdocs build failure with the helpful "Too deeply nested" error
message buried deeply in Documentation/output/filesystems.log.

Increase the "maxlistdepth" parameter to instruct LaTeX that it needs to
deal with the deeper nesting whether it wants to or not.

Suggested-by: Akira Yokosawa <akiyks@gmail.com>
Tested-by: Akira Yokosawa <akiyks@gmail.com>
Cc: stable@vger.kernel.org # v6.4+
Link: https://lore.kernel.org/linux-doc/67f6ac60-7957-4b92-9d72-a08fbad0e028@gmail.com/
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
13 months agodocs: admin-guide: Update bootloader and installation instructions
Hunter Chasens [Wed, 7 Feb 2024 17:10:07 +0000 (12:10 -0500)]
docs: admin-guide: Update bootloader and installation instructions

Updates the bootloader and installation instructions in
admin-guide/README.rst to align with modern practices.

Details of Changes:

 - Added guidance on using EFISTUB for UEFI/EFI systems.
 - Noted that LILO is no longer in active development and provides
   alternatives.
 - Kept LILO instructions but marked as Legacy LILO Instructions.
   Suggest removal in future patch.

Signed-off-by: Hunter Chasens <hunter.chasens18@ncf.edu>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
[jc: repaired added whitespace warnings]
Link: https://lore.kernel.org/r/20240207171007.45405-1-hunter.chasens18@ncf.edu
13 months agodocs: Makefile: Fix make cleandocs by deleting generated .rst files
Thorsten Blum [Thu, 8 Feb 2024 14:50:01 +0000 (15:50 +0100)]
docs: Makefile: Fix make cleandocs by deleting generated .rst files

The script tools/net/ynl/ynl-gen-rst.py (YNL_TOOL) generates several .rst
files (YNL_INDEX, YNL_RST_FILES) in Documentation/networking/netlink_spec
(YNL_RST_DIR) which are not deleted by make cleandocs.

Fix make cleandocs by deleting the generated .rst files.

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Reviewed-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240208145001.61769-1-thorsten.blum@toblux.com
13 months agoscripts/kernel-doc: reindent
Vegard Nossum [Thu, 8 Feb 2024 16:17:05 +0000 (17:17 +0100)]
scripts/kernel-doc: reindent

This file is using an ungodly mixture of 4 spaces, 2-wide tabs, 4-wide
tabs, _and_ 8-wide tabs, making it really hard to find good editor
settings for working with this file.

Bite the bullet and reindent it by hand. I tried using both perltidy
and vim, but neither of them were up to the task without changing too
much or getting confused about what they were supposed to be doing.

I did change a few instances of

    }
    else

into

    } else

(and same for elsif); the file is again written using both styles, and
I left functions which already seemed self-consistent alone.

You can verify that this commit only changes whitespace using e.g.:

    git diff --ignore-all-space --word-diff

or to see (only) the instances where newlines were added/removed:

    git diff --ignore-all-space

You can also see the delta from what perltidy would have wanted to
do to this file (when asked to only indent it), which isn't that much
in the end:

    perltidy -io -fnl scripts/kernel-doc
    git diff --no-index scripts/kernel-doc{,.tdy}

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240208161705.888385-1-vegard.nossum@oracle.com
13 months agodocs: scripts: sphinx-pre-install: Fix building docs with pyyaml package
Thorsten Blum [Thu, 8 Feb 2024 20:55:51 +0000 (21:55 +0100)]
docs: scripts: sphinx-pre-install: Fix building docs with pyyaml package

The Python module pyyaml is required to build the docs, but it is only
listed in Documentation/sphinx/requirements.txt and is therefore missing
when Sphinx is installed as a package and not via pip/pypi.

Add pyyaml as an optional package for multiple distros to fix building the
docs if you prefer to install Sphinx as a package.

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Reviewed-by: Vegard Nossum <vegard.nossum@oracle.com>
Tested-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240208205550.984-1-thorsten.blum@toblux.com
13 months agodoc:it_IT: add translation for I2C summary and protocol
Davide Benini [Fri, 9 Feb 2024 22:01:26 +0000 (23:01 +0100)]
doc:it_IT: add translation for I2C summary and protocol

This patch adds the italian translation for I2C subsystem summary and
protocol. Plus, a reference in the subsystem-apis page.

Signed-off-by: Davide Benini <davide.benini@gmail.com>
Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240209220126.28042-1-federico.vaga@vaga.pv.it
13 months agodoc:it_IT: remove unreferenced and not translated page
Federico Vaga [Fri, 9 Feb 2024 22:21:15 +0000 (23:21 +0100)]
doc:it_IT: remove unreferenced and not translated page

The netdev-FAQ page in the italian translation was creted to avoid
having broken links. With the evolution of the documentation this was
not referenced anymore, but the page never removed.

Reported-by: Davide Benini <davide.benini@gmail.com>
Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240209222115.31505-1-federico.vaga@vaga.pv.it
13 months agoDocumentation: embargoed-hardware-issues.rst: Fix Trilok's email
Jeffrey Hugo [Fri, 2 Feb 2024 16:41:19 +0000 (09:41 -0700)]
Documentation: embargoed-hardware-issues.rst: Fix Trilok's email

The servers for the @codeaurora domain have long been retired and any
messages addressed to @codeaurora will bounce.

Trilok has an entry in .mailmap, but the raw documentation files still
list an old @codeaurora address.  Update the address in the
documentation files for anyone reading them.

Signed-off-by: Jeffrey Hugo <quic_jhugo@quicinc.com>
Reviewed-by: Carlos Bilbao <carlos.bilbao@amd.com>
Reviewed-by: Trilok Soni <quic_tsoni@quicinc.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240202164119.4090703-1-quic_jhugo@quicinc.com
13 months agodocs: dev-tools: checkpatch.rst: Fix grammar
Thorsten Blum [Thu, 8 Feb 2024 15:20:40 +0000 (16:20 +0100)]
docs: dev-tools: checkpatch.rst: Fix grammar

- s/exists/exist/
- s/maybe/may be/

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240208152039.65293-1-thorsten.blum@toblux.com
13 months agoREADME: Fix spelling/capitalization
Thorsten Blum [Wed, 7 Feb 2024 12:21:31 +0000 (13:21 +0100)]
README: Fix spelling/capitalization

- Fix spelling/capitalization s/Restructured/ReStructured/

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240207122127.9182-1-thorsten.blum@toblux.com
13 months agodocs: proc.rst: comm: mention the included NUL
Christoph Anton Mitterer [Mon, 5 Feb 2024 15:41:00 +0000 (16:41 +0100)]
docs: proc.rst: comm: mention the included NUL

Indicate that the actual value will be one character less.

Signed-off-by: Christoph Anton Mitterer <mail@christoph.anton.mitterer.name>
Link: https://lore.kernel.org/r/20240205154100.736499-1-mail@christoph.anton.mitterer.name
[jc: did s/null/NUL/ ]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
13 months agodoc:it_IT: fix a typo in the config name in RCU torture
Lukas Bulwahn [Wed, 7 Feb 2024 15:03:22 +0000 (16:03 +0100)]
doc:it_IT: fix a typo in the config name in RCU torture

This issue was detected with the scripts/checkkconfigsymbols.py tool.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240207150322.20238-1-lukas.bulwahn@gmail.com
13 months agodocs: staging: fix typo in docs
Vincenzo Mezzela [Thu, 8 Feb 2024 16:27:48 +0000 (17:27 +0100)]
docs: staging: fix typo in docs

Resolve a spelling error in the documentation found
with codespell.

Signed-off-by: Vincenzo Mezzela <vincenzo.mezzela@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240208162748.111120-1-vincenzo.mezzela@gmail.com
13 months agodocs: kernel_feat.py: fix build error for missing files
Vegard Nossum [Mon, 5 Feb 2024 17:51:26 +0000 (18:51 +0100)]
docs: kernel_feat.py: fix build error for missing files

If the directory passed to the '.. kernel-feat::' directive does not
exist or the get_feat.pl script does not find any files to extract
features from, Sphinx will report the following error:

    Sphinx parallel build error:
    UnboundLocalError: local variable 'fname' referenced before assignment
    make[2]: *** [Documentation/Makefile:102: htmldocs] Error 2

This is due to how I changed the script in c48a7c44a1d0 ("docs:
kernel_feat.py: fix potential command injection"). Before that, the
filename passed along to self.nestedParse() in this case was weirdly
just the whole get_feat.pl invocation.

We can fix it by doing what kernel_abi.py does -- just pass
self.arguments[0] as 'fname'.

Fixes: c48a7c44a1d0 ("docs: kernel_feat.py: fix potential command injection")
Cc: Justin Forbes <jforbes@fedoraproject.org>
Cc: Salvatore Bonaccorso <carnil@debian.org>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Link: https://lore.kernel.org/r/20240205175133.774271-2-vegard.nossum@oracle.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
14 months agoDocumentation: admin-guide: tainted-kernels.rst: Add missing article and comma
Thorsten Blum [Mon, 5 Feb 2024 13:24:10 +0000 (14:24 +0100)]
Documentation: admin-guide: tainted-kernels.rst: Add missing article and comma

- Add missing article "the"
- s/above example/example above/
- Add missing comma after introductory clause to improve readability

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240205132409.1957-1-thorsten.blum@toblux.com
14 months agoDocumentation: multiple .rst files: Fix grammar and more consistent formatting
Thorsten Blum [Mon, 5 Feb 2024 00:01:17 +0000 (01:01 +0100)]
Documentation: multiple .rst files: Fix grammar and more consistent formatting

sphinx.rst:
- Remove unnecessary newline
- Fix grammar s/on/in/
- Fix grammar s/check/checks/
- Capitalize heading "The C domain"

changes.rst:
- Remove colon after "pahole" to be consistent with other entries

howto.rst:
- Fix grammar s/you will/will you/
- Hyphenate "real-world problems"

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240205000117.3285-1-thorsten.blum@toblux.com
14 months agoDocumentation: coding-style: Update syntax highlighting for code-blocks
Thorsten Blum [Sat, 3 Feb 2024 22:39:26 +0000 (23:39 +0100)]
Documentation: coding-style: Update syntax highlighting for code-blocks

Use c and elisp instead of none in code-blocks

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240203223926.5077-1-thorsten.blum@toblux.com
14 months agodocs: Document possible_cpus parameter
Guilherme G. Piccoli [Sat, 3 Feb 2024 15:21:13 +0000 (12:21 -0300)]
docs: Document possible_cpus parameter

The number of possible CPUs is set be kernel in early boot time through
some discovery mechanisms, like ACPI in x86. We have a parameter both
in x86 and S390 to override that - there are some cases of BIOSes exposing
more possible CPUs than the available ones, so this parameter is a good
testing mechanism, but for some reason wasn't mentioned so far in the
kernel parameters guide - let's fix that.

Cc: Changwoo Min <changwoo@igalia.com>
Signed-off-by: "Guilherme G. Piccoli" <gpiccoli@igalia.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240203152208.1461293-1-gpiccoli@igalia.com
14 months agoDocumentation: coding-style: Fix indentation in code-blocks
Thorsten Blum [Fri, 2 Feb 2024 23:13:16 +0000 (00:13 +0100)]
Documentation: coding-style: Fix indentation in code-blocks

- Remove spaces in C code-blocks to align error labels consistently
- Replace tab characters with spaces in emacs-lisp code blocks

Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240202231316.7606-1-thorsten.blum@toblux.com
14 months agodocs: maintainer: add existing SoC and netdev profiles
Krzysztof Kozlowski [Wed, 31 Jan 2024 12:53:51 +0000 (13:53 +0100)]
docs: maintainer: add existing SoC and netdev profiles

Extend the list of maintainer profiles with SoC and netdev.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240131125351.123509-1-krzysztof.kozlowski@linaro.org
14 months agokernel-doc: Support arrays of pointers struct fields
Sakari Ailus [Wed, 31 Jan 2024 08:49:34 +0000 (10:49 +0200)]
kernel-doc: Support arrays of pointers struct fields

In a rather unusual arrangement in include/media/v4l2-vp9.h struct
v4l2_vp9_frame_symbol_counts has fields that are arrays of pointers, not a
pointer to an array, which is what's usually done.

Add support for such arrays of pointers to kernel-doc.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240131084934.191226-1-sakari.ailus@linux.intel.com
14 months agocoding-style: Add guidance to prefer dev_dbg
Abhishek Pandit-Subedi [Fri, 26 Jan 2024 00:53:11 +0000 (16:53 -0800)]
coding-style: Add guidance to prefer dev_dbg

During review, it was suggested that drivers only emit messages when
something is wrong or it is a debug message. Document this as a formal
recommendation.

https://lore.kernel.org/linux-usb/2024012525-alienate-frown-916b@gregkh/

Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@chromium.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240125165311.1.I8d9c88e747e233917e527c7dad1feb8a18f070e2@changeid
14 months agodocs: Fix subsystem APIs page so ungrouped entries have their own header
Michael Kelley [Thu, 25 Jan 2024 04:59:41 +0000 (20:59 -0800)]
docs: Fix subsystem APIs page so ungrouped entries have their own header

The kernel subsystem APIs front page currently has four top-level
groupings with headers, and then everything else that isn't grouped.
But in the table-of-contents, ungrouped subsystems are indented as
if they were part of the preceding grouping (currently "Storage
interfaces"), which is confusing.

Fix this by adding an "Other subsystems" header for the ungrouped
subsystems.

Fixes: 3c591cc954d5 ("docs: consolidate human interface subsystems")
Signed-off-by: Michael Kelley <mhklinux@outlook.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240125045941.123297-1-mhklinux@outlook.com
14 months agodocs: sphinx-pre-install fix-noto-sans-cjk on fedora
Andrew Ballance [Wed, 24 Jan 2024 04:39:18 +0000 (22:39 -0600)]
docs: sphinx-pre-install fix-noto-sans-cjk on fedora

fedora 38 and later changed the directory and package name that
provides NotoSansCJK-Regular.ttc. this adds the new search path and
suggests the correct package if on fedora 38 or later.

Signed-off-by: Andrew Ballance <andrewjballance@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240124043918.31771-1-andrewjballance@gmail.com
14 months agoDocumentation: userspace-api: Document perf ring buffer mechanism
Leo Yan [Tue, 2 Jan 2024 08:50:01 +0000 (16:50 +0800)]
Documentation: userspace-api: Document perf ring buffer mechanism

In the Linux perf tool, the ring buffer serves not only as a medium for
transferring PMU event data but also as a vital mechanism for hardware
tracing using technologies like Intel PT and Arm CoreSight, etc.

Consequently, the ring buffer mechanism plays a crucial role by ensuring
high throughput for data transfer between the kernel and user space
while avoiding excessive overhead caused by the ring buffer itself.

This commit documents the ring buffer mechanism in detail.  It explains
the implementation of both the regular ring buffer and the AUX ring
buffer.  Additionally, it covers how these ring buffers support various
tracing modes and explains the synchronization with memory barriers.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Reviewed-by: James Clark <james.clark@arm.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240102085001.228815-1-leo.yan@linaro.org
14 months agodocs: rework the userspace-api top page
Jonathan Corbet [Mon, 22 Jan 2024 22:18:30 +0000 (15:18 -0700)]
docs: rework the userspace-api top page

Add some subsection headings and reorder entries so that the page makes a
bit more sense.  With luck, adding some ordering will also reduce merge
conflicts due to everybody adding new entries at the end.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/87ttn5m2q1.fsf@meer.lwn.net
14 months agodocs: rework the driver-api top-level page
Jonathan Corbet [Mon, 22 Jan 2024 22:19:19 +0000 (15:19 -0700)]
docs: rework the driver-api top-level page

Add subsections in an attempt to bring a bit order to this page; also sort
most subsections into alphabetical order.  With luck all this will help to
prevent merge conflicts on this page due to everybody adding entries at the
end.

Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/87plxtm2oo.fsf@meer.lwn.net
14 months agodoc:it_IT: first translation for locking/
Federico Vaga [Sat, 6 Jan 2024 23:38:20 +0000 (00:38 +0100)]
doc:it_IT: first translation for locking/

To begin with:
    - locking/index.rst
    - locking/lockdep-design.rst
    - locking/lockstat.rst
    - locking/lockturture.rst
    - locking/locktypes.rst

And RCU/torture.rst to avoid broken references.

Signed-off-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240106233820.30454-1-federico.vaga@vaga.pv.it
14 months agodoc-guide: kernel-doc: tell about object-like macros
Randy Dunlap [Sun, 7 Jan 2024 01:24:00 +0000 (17:24 -0800)]
doc-guide: kernel-doc: tell about object-like macros

Since 2014 kernel-doc has supported describing object-like macros
but it is not documented anywhere. I should have required some
documentation for it when I merged the patch. :(

There are currently only 3 uses of this (all in DRM headers, in
include/drm/*.h).

Add object-like macro kernel-doc documentation now so that more may
know about it and use it.

Fixes: cbb4d3e6510b ("scripts/kernel-doc: handle object-like macros")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240107012400.32587-1-rdunlap@infradead.org
14 months agokernel-doc: drop looking for "MACDOC"
Randy Dunlap [Mon, 8 Jan 2024 00:37:00 +0000 (16:37 -0800)]
kernel-doc: drop looking for "MACDOC"

Linux kernel does not use "MACDOC" in any documenation or any
source files, so stop searching for it.

Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240108003700.13418-1-rdunlap@infradead.org
14 months agodocs: add blurb about target audience to maintainer-profile
Vegard Nossum [Thu, 11 Jan 2024 09:48:38 +0000 (10:48 +0100)]
docs: add blurb about target audience to maintainer-profile

It's good to be clear about who the intended target audience for any
given piece of documentation is, as this will help us put new text in
the correct place. Let's encourage submitters to state it explicitly
rather than relying on where they placed it in the directory hierarchy
as there isn't necessarily a one-to-one correspondence between them.

Target audience: documentation contributors and reviewers.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240111094838.3695697-1-vegard.nossum@oracle.com
14 months agoscripts/kernel-doc: Do not process backslash lines in comments
Anna-Maria Behnsen [Mon, 22 Jan 2024 09:31:52 +0000 (10:31 +0100)]
scripts/kernel-doc: Do not process backslash lines in comments

To prevent this, do the pre-processing only for lines which are no
comments, e.g. do not start with ' *'.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240122093152.22536-3-anna-maria@linutronix.de
14 months agodrm/vram-helper: Fix 'multi-line' kernel-doc comments
Anna-Maria Behnsen [Mon, 22 Jan 2024 09:31:51 +0000 (10:31 +0100)]
drm/vram-helper: Fix 'multi-line' kernel-doc comments

Reformat lines in kernel-doc comments, which make use of the backslash at
the end to suggest it is a multi-line comment. kernel-doc is able to
process e.g. the short description of a function properly, even if it is
across two lines.

No functional change.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240122093152.22536-2-anna-maria@linutronix.de
14 months agodocs: admin-guide: remove obsolete advice related to SLAB allocator
Lukas Bulwahn [Thu, 30 Nov 2023 09:55:15 +0000 (10:55 +0100)]
docs: admin-guide: remove obsolete advice related to SLAB allocator

Commit 1db9d06aaa55 ("mm/slab: remove CONFIG_SLAB from all Kconfig and
Makefile") removes the config SLAB and makes the SLUB allocator the only
default allocator in the kernel. Hence, the advice on reducing OS jitter
due to kworker kernel threads to build with CONFIG_SLUB instead of
CONFIG_SLAB is obsolete.

Remove the obsolete advice to build with SLUB instead of SLAB.

Signed-off-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20231130095515.21586-1-lukas.bulwahn@gmail.com
14 months agodoc: admin-guide/kernel-parameters: remove useless comment
Vegard Nossum [Thu, 11 Jan 2024 08:52:20 +0000 (09:52 +0100)]
doc: admin-guide/kernel-parameters: remove useless comment

This comment about DRM drivers has been there since the first git
commit. It simply doesn't belong in kernel-parameters; remove it.

Signed-off-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240111085220.3693059-1-vegard.nossum@oracle.com
14 months agodocs/accel: correct links to mailing list archives
Hu Haowen [Thu, 18 Jan 2024 09:01:40 +0000 (17:01 +0800)]
docs/accel: correct links to mailing list archives

Since the mailing archive list lkml.org is obsolete, change the links into
lore.kernel.org's ones.

Signed-off-by: Hu Haowen <2023002089@link.tyut.edu.cn>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240118090140.4868-1-2023002089@link.tyut.edu.cn
14 months agodocs/sphinx: Fix TOC scroll hack for the home page
Gustavo Sousa [Tue, 23 Jan 2024 16:21:58 +0000 (13:21 -0300)]
docs/sphinx: Fix TOC scroll hack for the home page

When on the documentation home page, there won't be any ".current"
element since no entry from the TOC was selected yet. That results in a
javascript error. Fix that by only trying to set the scrollTop if we
have matches for current entries.

Signed-off-by: Gustavo Sousa <gustavo.sousa@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20240123162157.61819-2-gustavo.sousa@intel.com
14 months agoLinux 6.8-rc1
Linus Torvalds [Sun, 21 Jan 2024 22:11:32 +0000 (14:11 -0800)]
Linux 6.8-rc1

14 months agoMerge tag 'bcachefs-2024-01-21' of https://evilpiepirate.org/git/bcachefs
Linus Torvalds [Sun, 21 Jan 2024 22:01:12 +0000 (14:01 -0800)]
Merge tag 'bcachefs-2024-01-21' of https://evilpiepirate.org/git/bcachefs

Pull more bcachefs updates from Kent Overstreet:
 "Some fixes, Some refactoring, some minor features:

   - Assorted prep work for disk space accounting rewrite

   - BTREE_TRIGGER_ATOMIC: after combining our trigger callbacks, this
     makes our trigger context more explicit

   - A few fixes to avoid excessive transaction restarts on
     multithreaded workloads: fstests (in addition to ktest tests) are
     now checking slowpath counters, and that's shaking out a few bugs

   - Assorted tracepoint improvements

   - Starting to break up bcachefs_format.h and move on disk types so
     they're with the code they belong to; this will make room to start
     documenting the on disk format better.

   - A few minor fixes"

* tag 'bcachefs-2024-01-21' of https://evilpiepirate.org/git/bcachefs: (46 commits)
  bcachefs: Improve inode_to_text()
  bcachefs: logged_ops_format.h
  bcachefs: reflink_format.h
  bcachefs; extents_format.h
  bcachefs: ec_format.h
  bcachefs: subvolume_format.h
  bcachefs: snapshot_format.h
  bcachefs: alloc_background_format.h
  bcachefs: xattr_format.h
  bcachefs: dirent_format.h
  bcachefs: inode_format.h
  bcachefs; quota_format.h
  bcachefs: sb-counters_format.h
  bcachefs: counters.c -> sb-counters.c
  bcachefs: comment bch_subvolume
  bcachefs: bch_snapshot::btime
  bcachefs: add missing __GFP_NOWARN
  bcachefs: opts->compression can now also be applied in the background
  bcachefs: Prep work for variable size btree node buffers
  bcachefs: grab s_umount only if snapshotting
  ...

14 months agoMerge tag 'timers-core-2024-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git...
Linus Torvalds [Sun, 21 Jan 2024 19:14:40 +0000 (11:14 -0800)]
Merge tag 'timers-core-2024-01-21' of git://git./linux/kernel/git/tip/tip

Pull timer updates from Thomas Gleixner:
 "Updates for time and clocksources:

   - A fix for the idle and iowait time accounting vs CPU hotplug.

     The time is reset on CPU hotplug which makes the accumulated
     systemwide time jump backwards.

   - Assorted fixes and improvements for clocksource/event drivers"

* tag 'timers-core-2024-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  tick-sched: Fix idle and iowait sleeptime accounting vs CPU hotplug
  clocksource/drivers/ep93xx: Fix error handling during probe
  clocksource/drivers/cadence-ttc: Fix some kernel-doc warnings
  clocksource/drivers/timer-ti-dm: Fix make W=n kerneldoc warnings
  clocksource/timer-riscv: Add riscv_clock_shutdown callback
  dt-bindings: timer: Add StarFive JH8100 clint
  dt-bindings: timer: thead,c900-aclint-mtimer: separate mtime and mtimecmp regs

14 months agoMerge tag 'powerpc-6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc...
Linus Torvalds [Sun, 21 Jan 2024 19:04:29 +0000 (11:04 -0800)]
Merge tag 'powerpc-6.8-2' of git://git./linux/kernel/git/powerpc/linux

Pull powerpc fixes from Aneesh Kumar:

 - Increase default stack size to 32KB for Book3S

Thanks to Michael Ellerman.

* tag 'powerpc-6.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux:
  powerpc/64s: Increase default stack size to 32KB

14 months agobcachefs: Improve inode_to_text()
Kent Overstreet [Sun, 21 Jan 2024 17:19:01 +0000 (12:19 -0500)]
bcachefs: Improve inode_to_text()

Add line breaks - inode_to_text() is now much easier to read.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: logged_ops_format.h
Kent Overstreet [Sun, 21 Jan 2024 07:57:45 +0000 (02:57 -0500)]
bcachefs: logged_ops_format.h

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: reflink_format.h
Kent Overstreet [Sun, 21 Jan 2024 07:54:47 +0000 (02:54 -0500)]
bcachefs: reflink_format.h

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs; extents_format.h
Kent Overstreet [Sun, 21 Jan 2024 07:51:56 +0000 (02:51 -0500)]
bcachefs; extents_format.h

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: ec_format.h
Kent Overstreet [Sun, 21 Jan 2024 07:47:14 +0000 (02:47 -0500)]
bcachefs: ec_format.h

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: subvolume_format.h
Kent Overstreet [Sun, 21 Jan 2024 07:42:53 +0000 (02:42 -0500)]
bcachefs: subvolume_format.h

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: snapshot_format.h
Kent Overstreet [Sun, 21 Jan 2024 07:41:06 +0000 (02:41 -0500)]
bcachefs: snapshot_format.h

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: alloc_background_format.h
Kent Overstreet [Sun, 21 Jan 2024 05:01:52 +0000 (00:01 -0500)]
bcachefs: alloc_background_format.h

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: xattr_format.h
Kent Overstreet [Sun, 21 Jan 2024 04:59:15 +0000 (23:59 -0500)]
bcachefs: xattr_format.h

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: dirent_format.h
Kent Overstreet [Sun, 21 Jan 2024 04:57:10 +0000 (23:57 -0500)]
bcachefs: dirent_format.h

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: inode_format.h
Kent Overstreet [Sun, 21 Jan 2024 04:55:39 +0000 (23:55 -0500)]
bcachefs: inode_format.h

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs; quota_format.h
Kent Overstreet [Sun, 21 Jan 2024 04:53:52 +0000 (23:53 -0500)]
bcachefs; quota_format.h

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: sb-counters_format.h
Kent Overstreet [Sun, 21 Jan 2024 04:50:56 +0000 (23:50 -0500)]
bcachefs: sb-counters_format.h

bcachefs_format.h has gotten too big; let's do some organizing.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: counters.c -> sb-counters.c
Kent Overstreet [Sun, 21 Jan 2024 04:46:35 +0000 (23:46 -0500)]
bcachefs: counters.c -> sb-counters.c

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: comment bch_subvolume
Kent Overstreet [Sun, 21 Jan 2024 04:44:17 +0000 (23:44 -0500)]
bcachefs: comment bch_subvolume

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: bch_snapshot::btime
Kent Overstreet [Sun, 21 Jan 2024 04:35:41 +0000 (23:35 -0500)]
bcachefs: bch_snapshot::btime

Add a field to bch_snapshot for creation time; this will be important
when we start exposing the snapshot tree to userspace.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: add missing __GFP_NOWARN
Kent Overstreet [Wed, 17 Jan 2024 22:16:07 +0000 (17:16 -0500)]
bcachefs: add missing __GFP_NOWARN

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: opts->compression can now also be applied in the background
Kent Overstreet [Tue, 16 Jan 2024 21:20:21 +0000 (16:20 -0500)]
bcachefs: opts->compression can now also be applied in the background

The "apply this compression method in the background" paths now use the
compression option if background_compression is not set; this means that
setting or changing the compression option will cause existing data to
be compressed accordingly in the background.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: Prep work for variable size btree node buffers
Kent Overstreet [Tue, 16 Jan 2024 18:29:59 +0000 (13:29 -0500)]
bcachefs: Prep work for variable size btree node buffers

bcachefs btree nodes are big - typically 256k - and btree roots are
pinned in memory. As we're now up to 18 btrees, we now have significant
memory overhead in mostly empty btree roots.

And in the future we're going to start enforcing that certain btree node
boundaries exist, to solve lock contention issues - analagous to XFS's
AGIs.

Thus, we need to start allocating smaller btree node buffers when we
can. This patch changes code that refers to the filesystem constant
c->opts.btree_node_size to refer to the btree node buffer size -
btree_buf_bytes() - where appropriate.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: grab s_umount only if snapshotting
Su Yue [Mon, 15 Jan 2024 02:21:25 +0000 (10:21 +0800)]
bcachefs: grab s_umount only if snapshotting

When I was testing mongodb over bcachefs with compression,
there is a lockdep warning when snapshotting mongodb data volume.

$ cat test.sh
prog=bcachefs

$prog subvolume create /mnt/data
$prog subvolume create /mnt/data/snapshots

while true;do
    $prog subvolume snapshot /mnt/data /mnt/data/snapshots/$(date +%s)
    sleep 1s
done

$ cat /etc/mongodb.conf
systemLog:
  destination: file
  logAppend: true
  path: /mnt/data/mongod.log

storage:
  dbPath: /mnt/data/

lockdep reports:
[ 3437.452330] ======================================================
[ 3437.452750] WARNING: possible circular locking dependency detected
[ 3437.453168] 6.7.0-rc7-custom+ #85 Tainted: G            E
[ 3437.453562] ------------------------------------------------------
[ 3437.453981] bcachefs/35533 is trying to acquire lock:
[ 3437.454325] ffffa0a02b2b1418 (sb_writers#10){.+.+}-{0:0}, at: filename_create+0x62/0x190
[ 3437.454875]
               but task is already holding lock:
[ 3437.455268] ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs]
[ 3437.456009]
               which lock already depends on the new lock.

[ 3437.456553]
               the existing dependency chain (in reverse order) is:
[ 3437.457054]
               -> #3 (&type->s_umount_key#48){.+.+}-{3:3}:
[ 3437.457507]        down_read+0x3e/0x170
[ 3437.457772]        bch2_fs_file_ioctl+0x232/0xc90 [bcachefs]
[ 3437.458206]        __x64_sys_ioctl+0x93/0xd0
[ 3437.458498]        do_syscall_64+0x42/0xf0
[ 3437.458779]        entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.459155]
               -> #2 (&c->snapshot_create_lock){++++}-{3:3}:
[ 3437.459615]        down_read+0x3e/0x170
[ 3437.459878]        bch2_truncate+0x82/0x110 [bcachefs]
[ 3437.460276]        bchfs_truncate+0x254/0x3c0 [bcachefs]
[ 3437.460686]        notify_change+0x1f1/0x4a0
[ 3437.461283]        do_truncate+0x7f/0xd0
[ 3437.461555]        path_openat+0xa57/0xce0
[ 3437.461836]        do_filp_open+0xb4/0x160
[ 3437.462116]        do_sys_openat2+0x91/0xc0
[ 3437.462402]        __x64_sys_openat+0x53/0xa0
[ 3437.462701]        do_syscall_64+0x42/0xf0
[ 3437.462982]        entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.463359]
               -> #1 (&sb->s_type->i_mutex_key#15){+.+.}-{3:3}:
[ 3437.463843]        down_write+0x3b/0xc0
[ 3437.464223]        bch2_write_iter+0x5b/0xcc0 [bcachefs]
[ 3437.464493]        vfs_write+0x21b/0x4c0
[ 3437.464653]        ksys_write+0x69/0xf0
[ 3437.464839]        do_syscall_64+0x42/0xf0
[ 3437.465009]        entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.465231]
               -> #0 (sb_writers#10){.+.+}-{0:0}:
[ 3437.465471]        __lock_acquire+0x1455/0x21b0
[ 3437.465656]        lock_acquire+0xc6/0x2b0
[ 3437.465822]        mnt_want_write+0x46/0x1a0
[ 3437.465996]        filename_create+0x62/0x190
[ 3437.466175]        user_path_create+0x2d/0x50
[ 3437.466352]        bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs]
[ 3437.466617]        __x64_sys_ioctl+0x93/0xd0
[ 3437.466791]        do_syscall_64+0x42/0xf0
[ 3437.466957]        entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.467180]
               other info that might help us debug this:

[ 3437.469670] 2 locks held by bcachefs/35533:
               other info that might help us debug this:

[ 3437.467507] Chain exists of:
                 sb_writers#10 --> &c->snapshot_create_lock --> &type->s_umount_key#48

[ 3437.467979]  Possible unsafe locking scenario:

[ 3437.468223]        CPU0                    CPU1
[ 3437.468405]        ----                    ----
[ 3437.468585]   rlock(&type->s_umount_key#48);
[ 3437.468758]                                lock(&c->snapshot_create_lock);
[ 3437.469030]                                lock(&type->s_umount_key#48);
[ 3437.469291]   rlock(sb_writers#10);
[ 3437.469434]
                *** DEADLOCK ***

[ 3437.469670] 2 locks held by bcachefs/35533:
[ 3437.469838]  #0: ffffa0a02ce00a88 (&c->snapshot_create_lock){++++}-{3:3}, at: bch2_fs_file_ioctl+0x1e3/0xc90 [bcachefs]
[ 3437.470294]  #1: ffffa0a02b2b10e0 (&type->s_umount_key#48){.+.+}-{3:3}, at: bch2_fs_file_ioctl+0x232/0xc90 [bcachefs]
[ 3437.470744]
               stack backtrace:
[ 3437.470922] CPU: 7 PID: 35533 Comm: bcachefs Kdump: loaded Tainted: G            E      6.7.0-rc7-custom+ #85
[ 3437.471313] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[ 3437.471694] Call Trace:
[ 3437.471795]  <TASK>
[ 3437.471884]  dump_stack_lvl+0x57/0x90
[ 3437.472035]  check_noncircular+0x132/0x150
[ 3437.472202]  __lock_acquire+0x1455/0x21b0
[ 3437.472369]  lock_acquire+0xc6/0x2b0
[ 3437.472518]  ? filename_create+0x62/0x190
[ 3437.472683]  ? lock_is_held_type+0x97/0x110
[ 3437.472856]  mnt_want_write+0x46/0x1a0
[ 3437.473025]  ? filename_create+0x62/0x190
[ 3437.473204]  filename_create+0x62/0x190
[ 3437.473380]  user_path_create+0x2d/0x50
[ 3437.473555]  bch2_fs_file_ioctl+0x2ec/0xc90 [bcachefs]
[ 3437.473819]  ? lock_acquire+0xc6/0x2b0
[ 3437.474002]  ? __fget_files+0x2a/0x190
[ 3437.474195]  ? __fget_files+0xbc/0x190
[ 3437.474380]  ? lock_release+0xc5/0x270
[ 3437.474567]  ? __x64_sys_ioctl+0x93/0xd0
[ 3437.474764]  ? __pfx_bch2_fs_file_ioctl+0x10/0x10 [bcachefs]
[ 3437.475090]  __x64_sys_ioctl+0x93/0xd0
[ 3437.475277]  do_syscall_64+0x42/0xf0
[ 3437.475454]  entry_SYSCALL_64_after_hwframe+0x6e/0x76
[ 3437.475691] RIP: 0033:0x7f2743c313af
======================================================

In __bch2_ioctl_subvolume_create(), we grab s_umount unconditionally
and unlock it at the end of the function. There is a comment
"why do we need this lock?" about the lock coming from
commit 42d237320e98 ("bcachefs: Snapshot creation, deletion")
The reason is that __bch2_ioctl_subvolume_create() calls
sync_inodes_sb() which enforce locked s_umount to writeback all dirty
nodes before doing snapshot works.

Fix it by read locking s_umount for snapshotting only and unlocking
s_umount after sync_inodes_sb().

Signed-off-by: Su Yue <glass.su@suse.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: kvfree bch_fs::snapshots in bch2_fs_snapshots_exit
Su Yue [Tue, 16 Jan 2024 11:05:37 +0000 (19:05 +0800)]
bcachefs: kvfree bch_fs::snapshots in bch2_fs_snapshots_exit

bch_fs::snapshots is allocated by kvzalloc in __snapshot_t_mut.
It should be freed by kvfree not kfree.
Or umount will triger:

[  406.829178 ] BUG: unable to handle page fault for address: ffffe7b487148008
[  406.830676 ] #PF: supervisor read access in kernel mode
[  406.831643 ] #PF: error_code(0x0000) - not-present page
[  406.832487 ] PGD 0 P4D 0
[  406.832898 ] Oops: 0000 [#1] PREEMPT SMP PTI
[  406.833512 ] CPU: 2 PID: 1754 Comm: umount Kdump: loaded Tainted: G           OE      6.7.0-rc7-custom+ #90
[  406.834746 ] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.16.3-1-1 04/01/2014
[  406.835796 ] RIP: 0010:kfree+0x62/0x140
[  406.836197 ] Code: 80 48 01 d8 0f 82 e9 00 00 00 48 c7 c2 00 00 00 80 48 2b 15 78 9f 1f 01 48 01 d0 48 c1 e8 0c 48 c1 e0 06 48 03 05 56 9f 1f 01 <48> 8b 50 08 48 89 c7 f6 c2 01 0f 85 b0 00 00 00 66 90 48 8b 07 f6
[  406.837810 ] RSP: 0018:ffffb9d641607e48 EFLAGS: 00010286
[  406.838213 ] RAX: ffffe7b487148000 RBX: ffffb9d645200000 RCX: ffffb9d641607dc4
[  406.838738 ] RDX: 000065bb00000000 RSI: ffffffffc0d88b84 RDI: ffffb9d645200000
[  406.839217 ] RBP: ffff9a4625d00068 R08: 0000000000000001 R09: 0000000000000001
[  406.839650 ] R10: 0000000000000001 R11: 000000000000001f R12: ffff9a4625d4da80
[  406.840055 ] R13: ffff9a4625d00000 R14: ffffffffc0e2eb20 R15: 0000000000000000
[  406.840451 ] FS:  00007f0a264ffb80(0000) GS:ffff9a4e2d500000(0000) knlGS:0000000000000000
[  406.840851 ] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  406.841125 ] CR2: ffffe7b487148008 CR3: 000000018c4d2000 CR4: 00000000000006f0
[  406.841464 ] Call Trace:
[  406.841583 ]  <TASK>
[  406.841682 ]  ? __die+0x1f/0x70
[  406.841828 ]  ? page_fault_oops+0x159/0x470
[  406.842014 ]  ? fixup_exception+0x22/0x310
[  406.842198 ]  ? exc_page_fault+0x1ed/0x200
[  406.842382 ]  ? asm_exc_page_fault+0x22/0x30
[  406.842574 ]  ? bch2_fs_release+0x54/0x280 [bcachefs]
[  406.842842 ]  ? kfree+0x62/0x140
[  406.842988 ]  ? kfree+0x104/0x140
[  406.843138 ]  bch2_fs_release+0x54/0x280 [bcachefs]
[  406.843390 ]  kobject_put+0xb7/0x170
[  406.843552 ]  deactivate_locked_super+0x2f/0xa0
[  406.843756 ]  cleanup_mnt+0xba/0x150
[  406.843917 ]  task_work_run+0x59/0xa0
[  406.844083 ]  exit_to_user_mode_prepare+0x197/0x1a0
[  406.844302 ]  syscall_exit_to_user_mode+0x16/0x40
[  406.844510 ]  do_syscall_64+0x4e/0xf0
[  406.844675 ]  entry_SYSCALL_64_after_hwframe+0x6e/0x76
[  406.844907 ] RIP: 0033:0x7f0a2664e4fb

Signed-off-by: Su Yue <glass.su@suse.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: bios must be 512 byte algined
Kent Overstreet [Tue, 16 Jan 2024 16:38:04 +0000 (11:38 -0500)]
bcachefs: bios must be 512 byte algined

Fixes: 023f9ac9f70f bcachefs: Delete dio read alignment check
Reported-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: remove redundant variable tmp
Colin Ian King [Tue, 16 Jan 2024 11:07:23 +0000 (11:07 +0000)]
bcachefs: remove redundant variable tmp

The variable tmp is being assigned a value but it isn't being
read afterwards. The assignment is redundant and so tmp can be
removed.

Cleans up clang scan build warning:
warning: Although the value stored to 'ret' is used in the enclosing
expression, the value is never actually read from 'ret'
[deadcode.DeadStores]

Signed-off-by: Colin Ian King <colin.i.king@gmail.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: Improve trace_trans_restart_relock
Kent Overstreet [Tue, 16 Jan 2024 01:40:06 +0000 (20:40 -0500)]
bcachefs: Improve trace_trans_restart_relock

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: Fix excess transaction restarts in __bchfs_fallocate()
Kent Overstreet [Tue, 16 Jan 2024 01:37:23 +0000 (20:37 -0500)]
bcachefs: Fix excess transaction restarts in __bchfs_fallocate()

drop_locks_do() should not be used in a fastpath without first trying
the do in nonblocking mode - the unlock and relock will cause excessive
transaction restarts and potentially livelocking with other threads that
are contending for the same locks.

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: extents_to_bp_state
Kent Overstreet [Mon, 15 Jan 2024 23:19:52 +0000 (18:19 -0500)]
bcachefs: extents_to_bp_state

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>
14 months agobcachefs: bkey_and_val_eq()
Kent Overstreet [Mon, 15 Jan 2024 23:08:32 +0000 (18:08 -0500)]
bcachefs: bkey_and_val_eq()

Signed-off-by: Kent Overstreet <kent.overstreet@linux.dev>