What for? To improve the script maintainability.
1. License
As stated by Jonathan Corbet in the reply to my version 1, the SPDX line
is enough.
2. The to-do list comment
As suggested by Jonathan Corbet in reply to my version 3, this section
doesn't need to be transitioned. And so it is removed for clarity.
3. The historical changelog comments
As suggested by Jonathan Corbet in a reply to v3, this section can go.
I wanted to keep it, but since it doesn't contain copyright notices,
let's just have it clean and simple.
4. The "format of comments" comment block
As suggested by Jani Nikula in a reply to my first version of this
transformation, Documentation/doc-guide/kernel-doc.rst can serve as the
information hub for comment formatting. The section DESCRIPTION already
points there, so the original comment block can just be removed.
Suggested-by: Jonathan Corbet <corbet@lwn.net>
Suggested-by: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Tomasz Warniełło <tomasz.warniello@gmail.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Disliked-by: Akira Yokosawa <akiyks@gmail.com>
Link: https://lore.kernel.org/r/20220218181628.1411551-11-tomasz.warniello@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The NAME section provides the doc title, while SYNOPSIS contains
the basic syntax and usage description, which will be printed
in the help document and in the error output produced on wrong script
usage.
The rationale is to give users simple and succinct enlightment,
at the same time structuring the script internally for the maintainers.
In the synopsis, Rst-only options are grouped around rst, and the rest is
arranged as in the OPTIONS subsections (yet to be translated into POD,
check at the end of the series).
The third of the basic sections, DESCRIPTION, is added separately.
Signed-off-by: Tomasz Warniełło <tomasz.warniello@gmail.com>
Tested-by: Randy Dunlap <rdunlap@infradead.org>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Disliked-by: Akira Yokosawa <akiyks@gmail.com>
Link: https://lore.kernel.org/r/20220218181628.1411551-2-tomasz.warniello@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Pull documentation updates from Jonathan Corbet:
"This is a relatively unexciting cycle for documentation.
- Some small scripts/kerneldoc fixes
- More Chinese translation work, but at a much reduced rate.
- The tip-tree maintainer's handbook
...plus the usual array of build fixes, typo fixes, etc"
* tag 'docs-5.16' of git://git.lwn.net/linux: (53 commits)
kernel-doc: support DECLARE_PHY_INTERFACE_MASK()
docs/zh_CN: add core-api xarray translation
docs/zh_CN: add core-api assoc_array translation
speakup: Fix typo in documentation "boo" -> "boot"
docs: submitting-patches: make section about the Link: tag more explicit
docs: deprecated.rst: Clarify open-coded arithmetic with literals
scripts: documentation-file-ref-check: fix bpf selftests path
scripts: documentation-file-ref-check: ignore hidden files
coding-style.rst: trivial: fix location of driver model macros
docs: f2fs: fix text alignment
docs/zh_CN add PCI pci.rst translation
docs/zh_CN add PCI index.rst translation
docs: translations: zh_CN: memory-hotplug.rst: fix a typo
docs: translations: zn_CN: irq-affinity.rst: add a missing extension
block: add documentation for inflight
scripts: kernel-doc: Ignore __alloc_size() attribute
docs: pdfdocs: Adjust \headheight for fancyhdr
docs: UML: user_mode_linux_howto_v2 edits
docs: use the lore redirector everywhere
docs: proc.rst: mountinfo: align columns
...
Support the DECLARE_PHY_INTERFACE_MASK() macro that is used to declare
a bitmap by converting the macro to DECLARE_BITMAP(), as has been done
for the __ETHTOOL_DECLARE_LINK_MODE_MASK() macro.
This fixes a 'make htmldocs' warning:
include/linux/phylink.h:82: warning: Function parameter or member 'DECLARE_PHY_INTERFACE_MASK(supported_interfaces' not described in 'phylink_config'
that was introduced by commit
38c310eb46 ("net: phylink: add MAC phy_interface_t bitmap")
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Russell King (Oracle) <linux@armlinux.org.uk>
Link: https://lore.kernel.org/r/45934225-7942-4326-f883-a15378939db9@infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
There are many places where kernel code wants to have several different
typed trailing flexible arrays. This would normally be done with multiple
flexible arrays in a union, but since GCC and Clang don't (on the surface)
allow this, there have been many open-coded workarounds, usually involving
neighboring 0-element arrays at the end of a structure. For example,
instead of something like this:
struct thing {
...
union {
struct type1 foo[];
struct type2 bar[];
};
};
code works around the compiler with:
struct thing {
...
struct type1 foo[0];
struct type2 bar[];
};
Another case is when a flexible array is wanted as the single member
within a struct (which itself is usually in a union). For example, this
would be worked around as:
union many {
...
struct {
struct type3 baz[0];
};
};
These kinds of work-arounds cause problems with size checks against such
zero-element arrays (for example when building with -Warray-bounds and
-Wzero-length-bounds, and with the coming FORTIFY_SOURCE improvements),
so they must all be converted to "real" flexible arrays, avoiding warnings
like this:
fs/hpfs/anode.c: In function 'hpfs_add_sector_to_btree':
fs/hpfs/anode.c:209:27: warning: array subscript 0 is outside the bounds of an interior zero-length array 'struct bplus_internal_node[0]' [-Wzero-length-bounds]
209 | anode->btree.u.internal[0].down = cpu_to_le32(a);
| ~~~~~~~~~~~~~~~~~~~~~~~^~~
In file included from fs/hpfs/hpfs_fn.h:26,
from fs/hpfs/anode.c:10:
fs/hpfs/hpfs.h:412:32: note: while referencing 'internal'
412 | struct bplus_internal_node internal[0]; /* (internal) 2-word entries giving
| ^~~~~~~~
drivers/net/can/usb/etas_es58x/es58x_fd.c: In function 'es58x_fd_tx_can_msg':
drivers/net/can/usb/etas_es58x/es58x_fd.c:360:35: warning: array subscript 65535 is outside the bounds of an interior zero-length array 'u8[0]' {aka 'unsigned char[]'} [-Wzero-length-bounds]
360 | tx_can_msg = (typeof(tx_can_msg))&es58x_fd_urb_cmd->raw_msg[msg_len];
| ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In file included from drivers/net/can/usb/etas_es58x/es58x_core.h:22,
from drivers/net/can/usb/etas_es58x/es58x_fd.c:17:
drivers/net/can/usb/etas_es58x/es58x_fd.h:231:6: note: while referencing 'raw_msg'
231 | u8 raw_msg[0];
| ^~~~~~~
However, it _is_ entirely possible to have one or more flexible arrays
in a struct or union: it just has to be in another struct. And since it
cannot be alone in a struct, such a struct must have at least 1 other
named member -- but that member can be zero sized. Wrap all this nonsense
into the new DECLARE_FLEX_ARRAY() in support of having flexible arrays
in unions (or alone in a struct).
As with struct_group(), since this is needed in UAPI headers as well,
implement the core there, with a non-UAPI wrapper.
Additionally update kernel-doc to understand its existence.
https://github.com/KSPP/linux/issues/137
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Signed-off-by: Kees Cook <keescook@chromium.org>
Fixes "Compiler Attributes: add __alloc_size() for better bounds checking"
so that the __alloc_size() macro is ignored for function prototypes when
generating kerndoc. Avoids warnings like:
./include/linux/slab.h:662: warning: Function parameter or member '1' not described in '__alloc_size'
./include/linux/slab.h:662: warning: Function parameter or member '2' not described in '__alloc_size'
./include/linux/slab.h:662: warning: expecting prototype for kcalloc(). Prototype was for __alloc_size() instead
Suggested-by: Matthew Wilcox <willy@infradead.org>
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20211011180650.3603988-1-keescook@chromium.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Kernel code has a regular need to describe groups of members within a
structure usually when they need to be copied or initialized separately
from the rest of the surrounding structure. The generally accepted design
pattern in C is to use a named sub-struct:
struct foo {
int one;
struct {
int two;
int three, four;
} thing;
int five;
};
This would allow for traditional references and sizing:
memcpy(&dst.thing, &src.thing, sizeof(dst.thing));
However, doing this would mean that referencing struct members enclosed
by such named structs would always require including the sub-struct name
in identifiers:
do_something(dst.thing.three);
This has tended to be quite inflexible, especially when such groupings
need to be added to established code which causes huge naming churn.
Three workarounds exist in the kernel for this problem, and each have
other negative properties.
To avoid the naming churn, there is a design pattern of adding macro
aliases for the named struct:
#define f_three thing.three
This ends up polluting the global namespace, and makes it difficult to
search for identifiers.
Another common work-around in kernel code avoids the pollution by avoiding
the named struct entirely, instead identifying the group's boundaries using
either a pair of empty anonymous structs of a pair of zero-element arrays:
struct foo {
int one;
struct { } start;
int two;
int three, four;
struct { } finish;
int five;
};
struct foo {
int one;
int start[0];
int two;
int three, four;
int finish[0];
int five;
};
This allows code to avoid needing to use a sub-struct named for member
references within the surrounding structure, but loses the benefits of
being able to actually use such a struct, making it rather fragile. Using
these requires open-coded calculation of sizes and offsets. The efforts
made to avoid common mistakes include lots of comments, or adding various
BUILD_BUG_ON()s. Such code is left with no way for the compiler to reason
about the boundaries (e.g. the "start" object looks like it's 0 bytes
in length), making bounds checking depend on open-coded calculations:
if (length > offsetof(struct foo, finish) -
offsetof(struct foo, start))
return -EINVAL;
memcpy(&dst.start, &src.start, offsetof(struct foo, finish) -
offsetof(struct foo, start));
However, the vast majority of places in the kernel that operate on
groups of members do so without any identification of the grouping,
relying either on comments or implicit knowledge of the struct contents,
which is even harder for the compiler to reason about, and results in
even more fragile manual sizing, usually depending on member locations
outside of the region (e.g. to copy "two" and "three", use the start of
"four" to find the size):
BUILD_BUG_ON((offsetof(struct foo, four) <
offsetof(struct foo, two)) ||
(offsetof(struct foo, four) <
offsetof(struct foo, three));
if (length > offsetof(struct foo, four) -
offsetof(struct foo, two))
return -EINVAL;
memcpy(&dst.two, &src.two, length);
In order to have a regular programmatic way to describe a struct
region that can be used for references and sizing, can be examined for
bounds checking, avoids forcing the use of intermediate identifiers,
and avoids polluting the global namespace, introduce the struct_group()
macro. This macro wraps the member declarations to create an anonymous
union of an anonymous struct (no intermediate name) and a named struct
(for references and sizing):
struct foo {
int one;
struct_group(thing,
int two;
int three, four;
);
int five;
};
if (length > sizeof(src.thing))
return -EINVAL;
memcpy(&dst.thing, &src.thing, length);
do_something(dst.three);
There are some rare cases where the resulting struct_group() needs
attributes added, so struct_group_attr() is also introduced to allow
for specifying struct attributes (e.g. __align(x) or __packed).
Additionally, there are places where such declarations would like to
have the struct be tagged, so struct_group_tagged() is added.
Given there is a need for a handful of UAPI uses too, the underlying
__struct_group() macro has been defined in UAPI so it can be used there
too.
To avoid confusing scripts/kernel-doc, hide the macro from its struct
parsing.
Co-developed-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Keith Packard <keithp@keithp.com>
Acked-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/lkml/20210728023217.GC35706@embeddedor
Enhanced-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Link: https://lore.kernel.org/lkml/41183a98-bdb9-4ad6-7eab-5a7292a6df84@rasmusvillemoes.dk
Enhanced-by: Dan Williams <dan.j.williams@intel.com>
Link: https://lore.kernel.org/lkml/1d9a2e6df2a9a35b2cdd50a9a68cac5991e7e5f0.camel@intel.com
Enhanced-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://lore.kernel.org/lkml/YQKa76A6XuFqgM03@phenom.ffwll.local
Acked-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Since commit 2c12c8103d ("scripts/kernel-doc: optionally treat
warnings as errors"), the kernel-doc script will treat warnings as
errors when one of the following conditions is true:
- The KDOC_WERROR environment variable is non-zero
- The KCFLAGS environment variable contains -Werror
- The -Werror parameter is passed to kernel-doc
Checking KCFLAGS for -Werror allows piggy-backing on the C compiler
error handling. However, unlike the C compiler, kernel-doc has no
provision for -Wno-error. This makes compiling the kernel with -Werror
(to catch regressions) and W=1 (to enable more checks) always fail,
without the same possibility as offered by the C compiler to treating
some selected warnings as warnings despite the global -Werror setting.
To fix this, evaluate KDOC_WERROR after KCFLAGS, which allows disabling
the warnings-as-errors behaviour of kernel-doc selectively by setting
KDOC_WERROR=0.
Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Link: https://lore.kernel.org/r/20210730225401.4401-1-laurent.pinchart+renesas@ideasonboard.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
There are some regex expressions in the kernel-doc script, which are used
repeatedly in the script.
Reduce such expressions into variables, which can be used everywhere.
A quick manual check found that no errors and warnings were added/removed
in this process.
Suggested-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Aditya Srivastava <yashsri421@gmail.com>
Link: https://lore.kernel.org/r/20210514144244.25341-1-yashsri421@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The current linux-next tree has a new error:
./Documentation/gpu/drm-mm:445: ./drivers/gpu/drm/drm_prime.c:994: WARNING: Error in declarator or parameters
Invalid C declaration: Expecting "(" in parameters. [error at 17]
int __deprecated drm_prime_sg_to_page_array (struct sg_table *sgt, struct page **pages, int max_entries)
-----------------^
While we might consider that documenting a deprecated interface is not
necessarily best practice, removing the error is easy.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://lore.kernel.org/r/20210427114828.GY235567@casper.infradead.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Currently kernel-doc does not identify some cases of probable kernel
doc comments, for e.g. pointer used as declaration type for identifier,
space separated identifier, etc.
Some example of these cases in files can be:
i)" * journal_t * jbd2_journal_init_dev() - creates and initialises a journal structure"
in fs/jbd2/journal.c
ii) "* dget, dget_dlock - get a reference to a dentry" in
include/linux/dcache.h
iii) " * DEFINE_SEQLOCK(sl) - Define a statically allocated seqlock_t"
in include/linux/seqlock.h
Also improve identification for non-kerneldoc comments. For e.g.,
i) " * The following functions allow us to read data using a swap map"
in kernel/power/swap.c does follow the kernel-doc like syntax, but the
content inside does not adheres to the expected format.
Improve parsing by adding support for these probable attempts to write
kernel-doc comment.
Suggested-by: Jonathan Corbet <corbet@lwn.net>
Link: https://lore.kernel.org/lkml/87mtujktl2.fsf@meer.lwn.net
Signed-off-by: Aditya Srivastava <yashsri421@gmail.com>
Link: https://lore.kernel.org/r/20210414192529.9080-1-yashsri421@gmail.com
[ jc: fixed some line-length issues ]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Currently, kernel-doc start parsing the comment as a kernel-doc comment if
it starts with '/**', but does not take into account if the content inside
the comment too, adheres with the expected format.
This results in unexpected and unclear warnings for the user.
E.g., running scripts/kernel-doc -none mm/memcontrol.c emits:
"mm/memcontrol.c:961: warning: expecting prototype for do not fallback to current(). Prototype was for get_mem_cgroup_from_current() instead"
Here kernel-doc parses the corresponding comment as a kernel-doc comment
and expects prototype for it in the next lines, and as a result causing
this warning.
Provide a clearer warning message to the users regarding the same, if the
content inside the comment does not follow the kernel-doc expected format.
Signed-off-by: Aditya Srivastava <yashsri421@gmail.com>
Link: https://lore.kernel.org/r/20210329092945.13152-1-yashsri421@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
The previous attempt to properly handle literal blocks broke parsing of
parameter lines containing colons; fix it by tweaking the regex to
specifically exclude the "::" pattern while accepting lines containing
colons in general. Add a little documentation to the regex while in the
neighborhood.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Fixes: 8d295fbad6 ("kernel-doc: better handle '::' sequences")
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Right now, if one of the following headers end with a '::', the
kernel-doc script will do the wrong thing:
description|context|returns?|notes?|examples?
The real issue is with examples, as people could try to write
something like:
example::
/* Some C code */
and this won't be properly evaluated. So, improve the regex
to not catch '\w+::' regex for the above identifiers.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Link: https://lore.kernel.org/r/2cf44cf1fa42588632735d4fbc8e84304bdc235f.1616696051.git.mchehab+huawei@kernel.org
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Currently, kernel-doc warns for function prototype parsing on the
presence of attributes "__attribute_const__" and "__flatten" in the
definition.
There are 166 occurrences in ~70 files in the kernel tree for
"__attribute_const__" and 5 occurrences in 4 files for "__flatten".
Out of 166, there are 3 occurrences in three different files with
"__attribute_const__" and a preceding kernel-doc; and, 1 occurrence in
./mm/percpu.c for "__flatten" with a preceding kernel-doc. All other
occurrences have no preceding kernel-doc.
Add support for "__attribute_const__" and "__flatten" attributes.
A quick evaluation by running 'kernel-doc -none' on kernel-tree reveals
that no additional warning or error has been added or removed by the fix.
Suggested-by: Lukas Bulwahn <lukas.bulwahn@gmail.com>
Signed-off-by: Aditya Srivastava <yashsri421@gmail.com>
Link: https://lore.kernel.org/r/20210306113510.31023-1-yashsri421@gmail.com
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
