Add an introductory paragraph to Part Id - Streaming DMA mappings and move
the explanation of address constraints there, because it applies to all map
functions.
Clarify that streaming DMA can be used with memory which does not meet the
addressing constraints of a device, but it may fail in that case.
Make a note about SWIOTLB and link to the detailed description of it.
Do not mention platform-dependent allocation flags. The note may mislead
device driver authors into thinking that they should poke into and try to
second-guess the DMA API implementation. They definitely shouldn't.
Remove the claim that platforms with an IOMMU may not require physically
contiguous buffers. The current implementation explicitly rejects vmalloc
addresses, regardless of IOMMU.
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627101015.1600042-8-ptesarik@suse.com
Move the description of DMA mask from the documentation of dma_map_single()
to Part Ic - DMA addressing limitations and improve the wording.
Explain when a mask setting function may fail, and do not repeat this
explanation for each individual function.
Clarify which device parameters are updated by each mask setting function.
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627101015.1600042-7-ptesarik@suse.com
Move the DMA pool API documentation from Memory Management APIs to
dma-api.rst, replacing the outdated duplicate description there.
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627101015.1600042-6-ptesarik@suse.com
Document the dma_pool_zalloc() wrapper.
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
[jc: fixed up dma_pool_alloc() reference in dmapool.h]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627101015.1600042-5-ptesarik@suse.com
The wording sometimes suggests there are multiple functions for an
operation. This was in fact the case before PCI DMA API was removed, but
since there is only one API now, the documentation has become confusing.
To improve readability:
* Remove implicit references to the PCI DMA API (plurals, use of "both",
etc.)
* Where possible, refer to an actual function rather than a more generic
description of the operation.
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Reviewed-by: Bagas Sanjaya <bagasdotme@gmail.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627101015.1600042-4-ptesarik@suse.com
For consistency, always use the term "coherent" when talking about memory
that is not subject to CPU caching effects. The term "consistent" is a
relic of a long-removed PCI DMA API (pci_alloc_consistent() and
pci_free_consistent() functions).
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627101015.1600042-3-ptesarik@suse.com
Make sure that all occurrences are spelled "DMA API" (all uppercase, no
hyphen, no underscore).
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627101015.1600042-2-ptesarik@suse.com
The KernelVersion field has limited practical value. Git history
provides more accurate tracking of when features were introduced
and target kernel versions often change during development and
merge.
Label it optional.
Signed-off-by: Alison Schofield <alison.schofield@intel.com>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250626024101.792073-1-alison.schofield@intel.com
The HTML output seems to be correct, but when reading the raw rst file
it's annoying.
So use "|" for table the border.
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250628083205.1066472-1-richard@nod.at
Now that "inline_*" are just ordinary parser states, split them into two
separate functions, getting rid of some nested conditional logic.
The original process_inline() would simply ignore lines that didn't match
any of the regexes (those lacking the initial " * " marker). I have
preserved that behavior, but we should perhaps emit a warning instead.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627184000.132291-9-corbet@lwn.net
The processing of inline kerneldoc comments is a state like the rest, but
it was implemented as a set of separate substates. Just remove the
substate logic and make the inline states normal ones like the rest.
INLINE_ERROR was never actually used for anything, so just take it out.
No changes to the generated output.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627184000.132291-8-corbet@lwn.net
Reorganize process_export() to eliminate duplicated code, don't look for
exports in states where we don't expect them, and don't bother with normal
state-machine processing if an export declaration has been found.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627184000.132291-6-corbet@lwn.net
The type_param regex matches "@..." just fine, so the special-case branch
for that in dump_section() is never executed. Just remove it.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627184000.132291-4-corbet@lwn.net
Rather than having other code mucking around with this bit of internal
state, encapsulate it internally. Accumulate the description as a list of
strings, joining them at the end, which is a more efficient way of building
the text.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250627184000.132291-3-corbet@lwn.net
brd hasn't supported DAX for a long time but dax.rst
still suggests it as an example of how to write a DAX
supporting block driver.
Remove the reference, confuse less people.
Fixes: 7a862fbbde ("brd: remove dax support")
Signed-off-by: Daniel Palmer <daniel.palmer@sony.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250610-fixdasrstbrd20250610-v1-1-4abe3b7f381a@sony.com
conf.py is missing a SPDX header and doesn't really have
a proper python coding style. It also has an obsolete
commented LaTeX syntax that doesn't work anymore.
Clean it up a little bit with some help from autolints
and manual adjustments.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/063c106d96e86ca30c3266f7819f30b7247881ed.1750571906.git.mchehab+huawei@kernel.org
Those days, it is hard to install a virtual env that would
build docs with Sphinx 3.4.3, as even python 3.13 is not
compatible anymore with it.
/usr/bin/python3.9 -m venv sphinx_3.4.3
. sphinx_3.4.3/bin/activate
pip install -r Documentation/sphinx/min_requirements.txt
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/e38a44ee64ebfa37eac5f64e47af51c7ac051d5a.1750571906.git.mchehab+huawei@kernel.org
Most of the time, testing the full range of supported Sphinx
version is a waste of time and resources. Instead, the best is
to focus at the versions that are actually shipped by major
distros.
For it to work properly, we need to adjust the requirements for
them to start from first patch for each distro after the
minimal supported one. The requirements were re-adjusted to
avoid build breakages related to version incompatibilities.
Such builds were tested with:
./scripts/test_doc_build.py -m -a "SPHINXOPTS=-j8" "SPHINXDIRS=networking netlink/specs" --full
Change the logic to pick by default only such versions, adding
another parameter to do a comprehensive test.
While here, improve the script documentation to make it easier
to be used.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/a2b9b7775a185766643ea4b82b558de25b61d6c7.1750571906.git.mchehab+huawei@kernel.org
When one does:
make SPHINXDIRS="foo" htmldocs
All patterns would be relative to Documentation/foo, which
causes the include/exclude patterns like:
include_patterns = [
...
f'foo/*.{ext}',
]
to break. This is not what it is expected. Address it by
adding a logic to dynamically adjust the pattern when
SPHINXDIRS is used.
That allows adding parsers for other file types.
It should be noticed that include_patterns was added on
Sphinx 5.1:
https://www.sphinx-doc.org/en/master/usage/configuration.html#confval-include_patterns
So, a backward-compatible code is needed when we start
using it for real.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Donald Hunter <donald.hunter@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/429c9c670fe27860f5e4f29aaf72576a4ed52ad1.1750571906.git.mchehab+huawei@kernel.org
Move the last SPECIAL_SECTION special case into the proper handler
function, getting rid of more if/then/else logic. The leading-space
tracking was tightened up a bit in the move. Add some comments describing
what is going on.
No changes to the generated output.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250621203512.223189-10-corbet@lwn.net
Now that the function can actually fit into a human brain, add a few
comments. While I was at it, I switched to the trim_whitespace() helper
rather than open-coding it.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250621203512.223189-9-corbet@lwn.net
Separate out the end-of-comment logic into its own helper and remove the
duplicated code introduced earlier.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250621203512.223189-8-corbet@lwn.net
Move the recognition of this state to when we enter it, rather than when we
exit, eliminating some twisty logic along the way.
Some changes in output do result from this shift, generally for kerneldoc
comments that do not quite fit the format. See, for example,
struct irqdomain. As far as I can tell, the new behavior is more correct
in each case.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250621203512.223189-7-corbet@lwn.net
Merge the duplicated code back into a single implementation. Code movement
only, no logic changes.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250621203512.223189-6-corbet@lwn.net
The state known as BODY_WITH_BLANK_LINE really, in a convoluted way,
indicates a "special section" that is terminated by a blank line or the
beginning of a new section. That is either "@param: desc" sections, or the
weird "context" section that plays by the same rules.
Rename the state to SPECIAL_SECTION and split its processing into a
separate function; no real changes to the logic yet.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250621203512.223189-5-corbet@lwn.net
The BODY_MAYBE state really describes the "we are in a declaration" state.
Rename it accordingly, and split the handling of this state out from that
of the other BODY* states. This change introduces a fair amount of
duplicated code that will be coalesced in a later patch.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250621203512.223189-4-corbet@lwn.net
Pull the repeated "begin a section" logic into a single place and hide it
within the KernelEntry class.
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250621203512.223189-3-corbet@lwn.net
The regex in the BODY_WITH_BLANK_LINE case was looking for lines starting
with " * ", where exactly one space was allowed before the following text.
There are many kerneldoc comments where the authors have put multiple
spaces instead, leading to mis-formatting of the documentation.
Specifically, in this case, the description portion is associated with the
last of the parameters.
Allow multiple spaces in this context.
See, for example, synchronize_hardirq() and how its documentation is
formatted before and after the change.
Acked-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Tested-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250621203512.223189-2-corbet@lwn.net
Long before introduction of lore.kernel.org, people would link
to LKML threads on third-party archives (here spinics.net), which
in some cases can be unreliable (as these were outside of
kernel.org control). Replace links to them with lore counterparts
(if any).
Signed-off-by: Bagas Sanjaya <bagasdotme@gmail.com>
Reviewed-by: Simon Horman <horms@kernel.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250611065254.36608-2-bagasdotme@gmail.com
In commit b5325b2a27 ("coredump: hand a pidfd to the usermode coredump
helper") a new core_pattern specifier, %F, was added to provide a pidfs
to the usermode helper process referring to the crashed process.
Update the documentation to include the new core_pattern specifier.
Signed-off-by: Salvatore Bonaccorso <carnil@debian.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250612060204.1159734-1-carnil@debian.org
It appears that folks "less versed in kernel coding" think that its
good style to document every function, even if they have no useful
information to pass to the future readers of the code. This used
to be just a waste of space, but with increased kdoc format linting
it's also a burden when refactoring the code.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Joe Damato <joe@dama.to>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250614204258.61449-1-kuba@kernel.org
This patch fixes two minor typos in Documentation/filesystems/f2fs.rst:
- "ramdom" → "random"
- "reenable" → "re-enable"
The changes improve spelling and consistency in the documentation.
These issues were identified using the 'codespell' tool with the
following command:
$ find Documentation/ -path Documentation/translations -prune -o \
-name '*.rst' -print | xargs codespell
Signed-off-by: Yuanye Ma <yuanye.ma20@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250618225546.104949-1-yuanye.ma20@gmail.com
In the AMD P-States Performance Scale diagram, the labels for "Max Perf"
and "Lowest Perf" were incorrectly used to define the range for
"Desired Perf".The "Desired performance target" should be bounded by the
"Maximum requested performance" and the "Minimum requested performance",
which corresponds to "Max Perf" and "Min Perf", respectively.
Signed-off-by: Shouye Liu <shouyeliu@tencent.com>
Reviewed-by: Mario Limonciello <mario.limonciello@amd.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250620021658.92161-1-shouyeliu@gmail.com
Docutils emits a deprecation warning when the set_class() element method is
used; that warning disappears into the ether, but it also causes a crash
with docutils 0.19.
Avoid the deprecated function and just append directly to the "classes"
attribute like the documentation says instead.
Reported-by: Akira Yokosawa <akiyks@gmail.com>
Tested-by: Akira Yokosawa <akiyks@gmail.com>
Closes: https://lore.kernel.org/de7bae91-3200-481f-9db2-c0dc382c91dd@gmail.com/
Fixes: d6d1df92c2 ("docs: automarkup: Mark up undocumented entities too")
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
pull_task(), the original function to move the task from src_rq to the
dst_rq during load balancing was renamed to move_tasks() in commit
ddcdf6e7d9 ("sched: Rename load-balancing fields")
As a part of commit 163122b7fc ("sched/fair: Remove
double_lock_balance() from load_balance()"), move_task() was broken down
into detach_tasks() and attach_tasks() pair to avoid holding locks of
both src_rq and dst_rq at the same time during load balancing.
Despite the evolution of pull_task() over the years, the sched-stats
documentation remained unchanged. Update the documentation to refer to
detach_task() instead of pull_task() which is responsible for removing
the task from the src_rq during load balancing.
commit 1c055a0f5d ("sched: Move sched domain name out of
CONFIG_SCHED_DEBUG") moves sched domain name out of CONFIG_SCHED_DEBUG.
Update the documentation related to that.
Reviewed-by: K Prateek Nayak <kprateek.nayak@amd.com>
Suggested-by: Shrikanth Hegde <sshegde@linux.ibm.com>
Signed-off-by: Swapnil Sapkal <swapnil.sapkal@amd.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/r/20250430062559.1188661-1-swapnil.sapkal@amd.com
