Add a file to the Documentation directory to describe how file licenses
should be described in all kernel files, using the SPDX identifier, as well
as where all licenses should be in the kernel source tree for people to
refer to (LICENSES/).

Thanks to Kate and Greg for review and editing and Jonas for the
suggestions concerning the meta tags in the licenses files.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Reviewed-by: NJonas Oberg <jonas@fsfe.org>
Reviewed-by: NJonathan Corbet <corbet@lwn.net>
Reviewed-by: NPhilippe Ombredanne <pombredanne@nexb.com>
Reviewed-by: NKate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

The logic with inhibits warnings for definitions that is not
output is incomplete: it doesn't cover the cases where
OUTPUT_INTERNAL and OUTPUT_EXPORTED are used.

As the most common case is OUTPUT_ALL, place it first,
in order to optimize a litte bit the check logic.

Fixes: 2defb272 ("scripts: kernel-doc: apply filtering rules to warnings")
Reported-by: NRandy Dunlap <rdunlap@infradead.org>
Acked-and-Tested-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

This link is replicated in most filesystems' config stanzas.  Referring
to an archived version of that site is pointless as it mostly deals with
patches; user documentation is available elsewhere.
Signed-off-by: NAdam Borowski <kilobyte@angband.pl>
CC: Alexander Viro <viro@zeniv.linux.org.uk>
Reviewed-by: NDarrick J. Wong <darrick.wong@oracle.com>
Acked-by: NJan Kara <jack@suse.cz>
Acked-by: NDave Kleikamp <dave.kleikamp@oracle.com>
Acked-by: NDavid Sterba <dsterba@suse.com>
Acked-by: N"Yan, Zheng" <zyan@redhat.com>
Acked-by: NChao Yu <yuchao0@huawei.com>
Acked-by: NJaegeuk Kim <jaegeuk@kernel.org>
Acked-by: NSteve French <smfrench@gmail.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

drivers/md/faulty.c has been renamed to md-faulty.c after
following commit merged int to the main line.

  935fe098 .

But the file name in fault-injection.txt has not been changed.
Now the actual file name and document are in sync.
Signed-off-by: NMasanari Iida <standby24x7@gmail.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

 - Move errseq.rst into core-api
 - Add errseq to the core-api index
 - Promote the header to a more prominent header type, otherwise we get three
   entries in the table of contents.
 - Reformat the table to look nicer and be a little more proportional in
   terms of horizontal width per bit (the SF bit is still disproportionately
   large, but there's no way to fix that).
 - Include errseq kernel-doc in the errseq.rst
 - Neaten some kernel-doc markup
Signed-off-by: NMatthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: NJeff Layton <jlayton@redhat.com>
Reviewed-by: NRandy Dunlap <rdunlap@infradead.org>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Now that kernel-doc can hanle nested structs/unions, describe
such fields at w1_netlink_message_types.
Acked-by: NEvgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

When kernel-doc is called with output selection filters,
it will be called lots of time for a single file. If
there is a warning present there, it means that it may
print hundreds of identical warnings.

Worse than that, the -function NAME actually filters only
functions. So, it makes no sense at all to print warnings
for structs or enums.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

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: NMarkus Heiser <markus.heiser@darmarit.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMarkus Heiser <markus.heiser@darmarit.de>
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Acked-by: NJani Nikula <jani.nikula@intel.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Add documentation about typedefs for function prototypes and
move it to happen earlier.
Signed-off-by: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMauro Carvalho Chehab <mchehab@s-opensource.com>
Signed-off-by: NJonathan 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: NMarkus Heiser <markus.heiser@darmarit.de>
Reviewed-by: NDarren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: NJonathan 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: NMarkus Heiser <markus.heiser@darmarit.de>
Acked-by: NSteven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

A reference to printk-formats.txt didn't get updated when the file moved;
fix that.
Signed-off-by: NJonathan 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: NCengiz Can <cengizc@gmail.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Signed-off-by: NJonathan 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: NLu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

Signed-off-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJonathan Corbet <corbet@lwn.net>

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

Add my name to the list.
Signed-off-by: NKees Cook <keescook@chromium.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NJonathan 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: NGergo Huszty <huszty.gergo@digitaltrip.hu>
Signed-off-by: NJonathan 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: NAdam Borowski <kilobyte@angband.pl>
Acked-by: NOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Signed-off-by: NJonathan 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: NTobin C. Harding <me@tobin.cc>
Signed-off-by: NJonathan 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: NTobin C. Harding <me@tobin.cc>
Signed-off-by: NJonathan 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: NTobin C. Harding <me@tobin.cc>
[jc: downcased "kernel"]
Signed-off-by: NJonathan 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: NJonathan 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: NDarren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: NJonathan 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: NDarren Hart (VMware) <dvhart@infradead.org>
Signed-off-by: NJonathan 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: NRandy Dunlap <rdunlap@infradead.org>
[jc: tweaked the uuid_is_valid() kerneldoc]
Signed-off-by: NJonathan Corbet <corbet@lwn.net>