It is possible to use nested structs like:

struct {
	struct {
		void *arg1;
	} st1, st2, *st3, st4;
};

Handling it requires to split each parameter. Change the logic
to allow such definitions.

In order to test the new nested logic, the following file
was used to test

<code>
struct foo { int a; }; /* Just to avoid errors if compiled */

/**
 * struct my_struct - a struct with nested unions and structs
 * @arg1: first argument of anonymous union/anonymous struct
 * @arg2: second argument of anonymous union/anonymous struct
 * @arg1b: first argument of anonymous union/anonymous struct
 * @arg2b: second argument of anonymous union/anonymous struct
 * @arg3: third argument of anonymous union/anonymous struct
 * @arg4: fourth argument of anonymous union/anonymous struct
 * @bar.st1.arg1: first argument of struct st1 on union bar
 * @bar.st1.arg2: second argument of struct st1 on union bar
 * @bar.st1.bar1: bar1 at st1
 * @bar.st1.bar2: bar2 at st1
 * @bar.st2.arg1: first argument of struct st2 on union bar
 * @bar.st2.arg2: second argument of struct st2 on union bar
 * @bar.st3.arg2: second argument of struct st3 on union bar
 * @f1: nested function on anonimous union/struct
 * @bar.st2.f2: nested function on named union/struct
 */
struct my_struct {
   /* Anonymous union/struct*/
   union {
	struct {
	    char arg1 : 1;
	    char arg2 : 3;
	};
       struct {
           int arg1b;
           int arg2b;
       };
       struct {
           void *arg3;
           int arg4;
           int (*f1)(char foo, int bar);
       };
   };
   union {
       struct {
           int arg1;
           int arg2;
	   struct foo bar1, *bar2;
       } st1;           /* bar.st1 is undocumented, cause a warning */
       struct {
           void *arg1;  /* bar.st3.arg1 is undocumented, cause a warning */
	    int arg2;
          int (*f2)(char foo, int bar); /* bar.st3.fn2 is undocumented, cause a warning */
       } st2, st3, *st4;
       int (*f3)(char foo, int bar); /* f3 is undocumented, cause a warning */
   } bar;               /* bar is undocumented, cause a warning */

   /* private: */
   int undoc_privat;    /* is undocumented but private, no warning */

   /* public: */
   int undoc_public;    /* is undocumented, cause a warning */
};
</code>

It produces the following warnings, as expected:

test2.h:57: warning: Function parameter or member 'bar' not described in 'my_struct'
test2.h:57: warning: Function parameter or member 'bar.st1' not described in 'my_struct'
test2.h:57: warning: Function parameter or member 'bar.st2' not described in 'my_struct'
test2.h:57: warning: Function parameter or member 'bar.st3' not described in 'my_struct'
test2.h:57: warning: Function parameter or member 'bar.st3.arg1' not described in 'my_struct'
test2.h:57: warning: Function parameter or member 'bar.st3.f2' not described in 'my_struct'
test2.h:57: warning: Function parameter or member 'bar.st4' not described in 'my_struct'
test2.h:57: warning: Function parameter or member 'bar.st4.arg1' not described in 'my_struct'
test2.h:57: warning: Function parameter or member 'bar.st4.arg2' not described in 'my_struct'
test2.h:57: warning: Function parameter or member 'bar.st4.f2' not described in 'my_struct'
test2.h:57: warning: Function parameter or member 'bar.f3' not described in 'my_struct'
test2.h:57: warning: Function parameter or member 'undoc_public' not described in 'my_struct'
Suggested-by: Markus Heiser <markus.heiser@darmarit.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Function arguments are different than usual ones. So, an
special logic is needed in order to handle such arguments
on nested structs.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The logic at create_parameterlist()'s ancillary push_parameter()
function has already a way to output the declaration name, with
would help to discover what declaration is missing.

However, currently, the logic is utterly broken, as it uses
the var $type with a wrong meaning. With the current code,
it will never print anything. I suspect that originally
it was using the second argument of output_declaration().

I opted to not rely on a globally defined $declaration_name,
but, instead, to pass it explicitly as a parameter.

While here, I removed a unaligned check for !$anon_struct_union.
This is not needed, as, if $anon_struct_union is not zero,
$parameterdescs{$param} will be defined.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The check_sections() function has a $nested parameter, meant
to identify when a nested struct is present. As we now have
a logic that handles it, get rid of such parameter.
Suggested-by: Markus Heiser <markus.heiser@darmarit.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

There are several places within the Kernel tree with nested
structs/unions, like this one:

  struct ingenic_cgu_clk_info {
    const char *name;
    enum {
      CGU_CLK_NONE = 0,
      CGU_CLK_EXT = BIT(0),
      CGU_CLK_PLL = BIT(1),
      CGU_CLK_GATE = BIT(2),
      CGU_CLK_MUX = BIT(3),
      CGU_CLK_MUX_GLITCHFREE = BIT(4),
      CGU_CLK_DIV = BIT(5),
      CGU_CLK_FIXDIV = BIT(6),
      CGU_CLK_CUSTOM = BIT(7),
    } type;
    int parents[4];
    union {
      struct ingenic_cgu_pll_info pll;
      struct {
        struct ingenic_cgu_gate_info gate;
        struct ingenic_cgu_mux_info mux;
        struct ingenic_cgu_div_info div;
        struct ingenic_cgu_fixdiv_info fixdiv;
      };
      struct ingenic_cgu_custom_info custom;
    };
  };

Currently, such struct is documented as:

	**Definition**

	::
	struct ingenic_cgu_clk_info {
	    const char * name;
	};

	**Members**

	``name``
	  name of the clock

With is obvioulsy wrong. It also generates an error:
	drivers/clk/ingenic/cgu.h:169: warning: No description found for parameter 'enum'

However, there's nothing wrong with this kernel-doc markup: everything
is documented there.

It makes sense to document all fields there. So, add a
way for the core to parse those structs.

With this patch, all documented fields will properly generate
documentation.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Sphinx has a hard time dealing with tabs, causing it to
misinterpret paragraph continuation.

As we're now mainly focused on supporting ReST output,
replace tabs by spaces, in order to avoid troubles when
the output is parsed by Sphinx.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Right now, if kernel-doc is called without arguments, it
defaults to man pages. IMO, it makes more sense to
default to ReST, as this is the output that it is most
used nowadays, and it easier to check if everything got
parsed fine on an enriched text mode format.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Right now, if one uses "--rst" instead of "-rst", it just
ignore the argument and produces a man page. Change the
logic to accept both "-cmd" and "--cmd". Also, if
"cmd" doesn't exist, print the usage information and exit.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Since there isn't any docbook code anymore upstream,
we can get rid of several output formats:

- docbook/xml, html, html5 and list formats were used by
  the old build system;
- As ReST is text, there's not much sense on outputting
  on a different text format.

After this patch, only man and rst output formats are
supported.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Everything there is already described at
Documentation/doc-guide/kernel-doc.rst. So, there's no reason why
to keep it anymore.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

kernel-doc-nano-HOWTO.txt has a chapter about man pages
production. While we don't have a working  "make manpages"
target, add it.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Add documentation about typedefs for function prototypes and
move it to happen earlier.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

There is a mess on this chapter: it suggests that even
enums and unions should be documented with "struct". That's
not the way it should be ;-)

Fix it and move it to happen earlier.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Move its contents to happen earlier and improve the description
of return values, adding a subsection to it. Most of the contents
there came from kernel-doc-nano-HOWTO.txt.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

The private members section can now be moved to be together
with the arguments section. Move it there and add an example
about the usage of public:
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Add a new section to describe kernel-doc arguments,
adding examples about how identation should happen, as failing
to do that causes Sphinx to do the wrong thing.
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

add missing indent whitespace to list item, fixes the warning:

- process/submit-checklist.rst:41: WARNING: Enumerated list ends without a blank
  line; unexpected unindent.
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
Reviewed-by: Darren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

ftrace-uses.rst is not yet included into any toctree, but since it is
a .rst file, it is parsed by the Sphinx build. Thats, why we see some
WARNINGS:

- trace/ftrace-uses.rst:53: WARNING: Definition list ends without a blank line; unexpected unindent.
- trace/ftrace-uses.rst:89: WARNING: Inline emphasis start-string without end-string.
- trace/ftrace-uses.rst:89: WARNING: Inline emphasis start-string without end-strin

Fixing the code-block directives results in a less noisy build, but the 'not
included' WARNING will be stay:

- trace/ftrace-uses.rst: WARNING: document isn't included in any toctree
Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

A reference to printk-formats.txt didn't get updated when the file moved;
fix that.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

`Documentation/i2c/dev-interface` gives examples for accessing i2c from
userspace.

There's a note that warns developers about the two `i2c-dev.h` header
files which were shipped with the kernel and i2c-tools separately.

However, following i2c-tools commits suggest that the header files are now
identical (in functionality) and `i2c_*` helper functions are now defined
in a separate header called `i2c/smbus.h`, which is distributed with
i2c-tools:

commit 652619121974 ("Minimize differences with kernel flavor")
commit 93caf007f4cb ("Move SMBus helper functions to include/i2c/smbus.h")

Thus, I've converted the warning paragraph into a historical note and
updated the suggested header files.
Signed-off-by: Cengiz Can <cengizc@gmail.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Update Documentation/driver-api/usb/usb3-debug-port.rst. This update
includes the guide for using xHCI debug capability based TTY serial
link.

Cc: Mathias Nyman <mathias.nyman@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Add my name to the list.
Signed-off-by: Luis R. Rodriguez <mcgrof@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Add my name to the list.
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Onewire devices has 6 byte long unique serial numbers, 1 byte family
code and 1 byte CRC. Linux sysfs presents the device folder in the
form of familyID-deviceID, so CRC is not shown. The consequence is
that the device serial number is always a 12 long hex-string, but
doc says 13 in one place. This is corrected by this change.
Reference: https://en.wikipedia.org/wiki/1-WireSigned-off-by: Gergo Huszty <huszty.gergo@digitaltrip.hu>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

All non-historic operating systems support the full range of Unicode here,
thus you can make filenames for example in Gothic (𐌼𐌴𐍉𐍅), the other Gothic
(𝓂ℯℴ𝓌) or the third Gothic (𝗆𝖾𝗈𝗐), or declare something as 💩.

Characters above U+FFFF are encoded on four bytes.
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Acked-by: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Hashing addresses printed with printk specifier %p was implemented
recently. During development a number of issues were raised regarding
leaking kernel addresses to userspace. Other documentation was updated but
security/self-protection missed out.

Add self-protection documentation regarding printing kernel addresses.
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Recently the behaviour of printk specifier %pK was changed. The
documentation does not currently mirror this.

Update documentation for sysctl kptr_restrict.
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Documentation/printk-formats.txt is a candidate for conversion to
ReStructuredText format. Some effort has already been made to do this
conversion even thought the suffix is currently .txt

Changes required to complete conversion

 - Move printk-formats.txt to core-api/printk-formats.rst
 - Add entry to Documentation/core-api/index.rst
 - Remove entry from Documentation/00-INDEX
 - Fix minor grammatical errors.
 - Order heading adornments as suggested by rst docs.
 - Use 'Passed by reference' uniformly.
 - Update pointer documentation around %px specifier.
 - Fix erroneous double backticks (to commas).
 - Remove extraneous double backticks (suggested by Jonathan Corbet).
 - Simplify documentation for kobject.
Signed-off-by: Tobin C. Harding <me@tobin.cc>
[jc: downcased "kernel"]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This warning will happen for every normal kernel docs build and doesn't
carry any useful information.  Should anybody actually depend on this
"version" variable (which isn't clear to me), the "unknown version" value
will be clue enough.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Add default value review to the submit checklist, referring to the
preference for "default n" from the previous patch added to
Documentation/kbuild/kconfig-language.txt.

Cc: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <mmarek@suse.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-kbuild@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Document the preference [1] for new CONFIG options to "default n" (or
not use default at all) in order to minimizes changes to the config,
especially to avoid "make oldconfig" growing unnecessarily from release
to release.

Document the exceptions where it is acceptable to use "default y/m" for
new CONFIG options.

1. https://lkml.org/lkml/2017/11/18/257

Cc: "Yann E. MORIN" <yann.morin.1998@free.fr>
Cc: Masahiro Yamada <yamada.masahiro@socionext.com>
Cc: Michal Marek <mmarek@suse.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: linux-kbuild@vger.kernel.org
Cc: linux-doc@vger.kernel.org
Signed-off-by: Darren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Update kernel-doc notation in lib/uuid.c and then add UUID/GUID
function interfaces to kernel-api.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
[jc: tweaked the uuid_is_valid() kerneldoc]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Add sort() and list_sort() to the kernel API documentation in a
new "Sorting" section.
Signed-off-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Commit ac1f5912 ("kernel/watchdog.c: add sysctl knob
hardlockup_panic") added the hardlockup_panic sysctl, but did not add it
to Documentation/sysctl/kernel.txt.  Add this, and reference it from the
corresponding entry in Documentation/admin-guide/kernel-parameters.txt.
Signed-off-by: Scott Wood <swood@redhat.com>
Acked-by: Christoph von Recklinghausen <crecklin@redhat.com>
Acked-by: Don Zickus <dzickus@redhat.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Fix the spelling of 'enumerate' in this document.
Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

...just enough to say what the purpose is and to solicit more
contributions.
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

There is currently very little documentation in the kernel on maintainer
level tasks. In particular there are no documents on creating pull
requests to submit to Linus.

Quoting Greg Kroah-Hartman on LKML:

    Anyway, this actually came up at the kernel summit / maintainer
    meeting a few weeks ago, in that "how do I make a
    good pull request to Linus" is something we need to document.

    Here's what I do, and it seems to work well, so maybe we should turn
    it into the start of the documentation for how to do it.

(quote references: kernel summit, Europe 2017)

Create a new kernel documentation book 'how to be a maintainer'
(suggested by Jonathan Corbet). Add chapters on 'configuring git' and
'creating a pull request'.

Most of the content was written by Linus Torvalds and Greg Kroah-Hartman
in discussion on LKML. This is stated at the start of one of the
chapters and the original email thread is referenced in
'pull-requests.rst'.
Signed-off-by: Tobin C. Harding <me@tobin.cc>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

Some functions from refcount_t API provide different
memory ordering guarantees that their atomic counterparts.
This adds a document outlining these differences (
Documentation/core-api/refcount-vs-atomic.rst) as well as
some other minor improvements.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>

This link is dead:

    $ curl -vI http://usb.cs.tum.edu/usbdoc
    * Could not resolve host: usb.cs.tum.edu
    * Closing connection 0
    curl: (6) Could not resolve host: usb.cs.tum.edu

I found the document somewhere else. Let's replace it.
Signed-off-by: Stefan Tatschner <stefan.tatschner@gmail.com>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>