Further up in the state machinery we switch from STATE_NAME to
STATE_DOCBLOCK when we match /$doc_block/. Which means this block of
code here is entirely unreachable, unless there are multiple DOC:
sections within a single kernel-doc comment.

Getting a list of all the files with more than one DOC: section using

$ git grep -c " * DOC:" | grep -v ":1$"

and then doing a full audit of them reveals there are no such comment
blocks in the kernel.

Supporting multiple DOC: sections in a single kernel-doc comment does
not seem like a recommended way of doing things anyway, so nuke the code
for simplicity.

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: linux-doc@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
[Jani: amended the commit message]
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

With this error output becomes almost readable. The line numbers are
still totally bonghits, but that's a lot harder to pull out of
kerneldoc. We'd essentially have to insert some special markers in the
kernel-doc output, split the output along these markers and then
insert each block separately using

     state_machine.insert_input(block, source, first_line)

Cc: Jani Nikula <jani.nikula@intel.com>
Cc: linux-doc@vger.kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: NDaniel Vetter <daniel.vetter@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Reconcile differences between python2 and python3 on dealing with
stdout, stderr from Popen. This fixes "name 'unicode' is not defined"
errors on python3. We'll need to try to keep the extension working on
both python-sphinx and python3-sphinx so we don't need two copies.
Reported-and-tested-by: NMarius Vlad <marius.c.vlad@intel.com>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

If the documentation comment does not have params or sections, the
section heading may leak from the previous documentation comment.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

If there are multiple sections with the same section name, the current
implementation results in several sections by the same heading, with the
content duplicated from the last section to all. Even if there's the
error message, a more graceful approach is to combine all the
identically named sections into one, with concatenated contents.

With the supported sections already limited to select few, there are
massively fewer collisions than there used to be, but this is still
useful for e.g. when function parameters are documented in the middle of
a documentation comment, with description spread out above and
below. (This is not a recommended documentation style, but used in the
kernel nonetheless.)

We can now also demote the error to a warning.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

kernel-doc currently identifies anything matching "section header:"
(specifically a string of word characters and spaces followed by a
colon) as a new section in the documentation comment, and renders the
section header accordingly.

Unfortunately, this turns all uses of colon into sections, mostly
unintentionally. Considering the output, erroneously creating sections
when not intended is always worse than erroneously not creating sections
when intended. For example, a line with "http://example.com" turns into
a "http" heading followed by "//example.com" in normal text style, which
is quite ugly. OTOH, "WARNING: Beware of the Leopard" is just fine even
if "WARNING" does not turn into a heading.

It is virtually impossible to change all the kernel-doc comments, either
way. The compromise is to pick the most commonly used and depended on
section headers (with variants) and accept them as section headers.

The accepted section headers are, case insensitive:

 * description:
 * context:
 * return:
 * returns:

Additionally, case sensitive:

 * @return:

All of the above are commonly used in the kernel-doc comments, and will
result in worse output if not identified as section headers. Also,
kernel-doc already has some special handling for all of them, so there's
nothing particularly controversial in adding more special treatment for
them.

While at it, improve the whitespace handling surrounding section
names. Do not consider the whitespace as part of the name.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Yes, for our purposes the type should contain typedef.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The latter isn't special to rst.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

If a param description spans multiple lines, check any leading
whitespace in the first continuation line, and remove same amount of
whitespace from following lines.

This allows indentation in the multi-line parameter descriptions for
aesthetical reasons while not causing accidentally significant
indentation in the rst output.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Handle whitespace on the first line of param text as if it was the empty
string. There is no need to add the newline in this case. This improves
the rst output in particular, where blank lines may be problematic in
parameter lists.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Move away from field lists, and simply use **strong emphasis** for
section headings on lines of their own. Do not use rst section headings,
because their nesting depth depends on the surrounding context, which
kernel-doc has no knowledge of. Also, they do not need to end up in any
table of contexts or indexes.

There are two related immediate benefits. Field lists are typically
rendered in two columns, while the new style uses the horizontal width
better. With no extra indent on the left, there's no need to be as fussy
about it. Field lists are more susceptible to indentation problems than
the new style.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The inline member markup allows whitespace lines before the actual
documentation starts. Strip the leading blank lines. This improves the
rst output.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Current approach leads to two blank lines, while one is enough.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

No functional changes.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The use of these is confusing in the script, and per this grep, they're
not used anywhere anyway:

$ git grep " \* [%$&][a-zA-Z0-9_]*:" -- *.[ch] | grep -v "\$\(Id\|Revision\|Date\)"

While at it, throw out the constants array, nothing is ever put there
again.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Let the user use @foo, &bar, %baz, etc. in the first kernel-doc purpose
line too.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

This bit is already done by xml_unescape() above.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Link "&foo->bar", "&foo->bar()", "&foo.bar", and "&foo.bar()" to the
struct/union/enum foo definition. The members themselves do not
currently have anchors to link to, but this is better than nothing, and
promotes a universal notation.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Let the user use "&union foo" and "&typedef foo" to reference foo. The
difference to using "union &foo", "typedef &foo", or just "&foo" (which
are valid too) is that "union" and "typedef" become part of the link
text.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

It's possible to use &foo to reference structs, enums, typedefs, etc. in
the Sphinx C domain. Thus do not prefix the links with "struct".
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The Sphinx C domain spec says function references should include the
parens ().
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

If the user requests a specific DOC: section by name, do not output its
section title. In these cases, the surrounding context already has a
heading, and the DOC: section title is only used as an identifier and a
heading for clarity in the source file.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Make the output selection a bit more readable by adding constants for
the various types of output selection. While at it, actually call the
variable for choosing what to output $output_selection.

No functional changes.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Make the state machine a bit more readable by adding constants for
parser states and inline member documentation parser substates. While at
it, rename the "split" documentation to "inline" documentation.

No functional changes.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Add "struct" in the label of the reference.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Function references should include the parens (), struct references
should not include "struct".
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

This script uses pandoc to convert existing DocBook template files to RST
templates.  A couple of sed scripts are need to massage things both before
and after the conversion, but the result is then usable with no hand
editing.

[Jani: Change usage to tmplcvt <in> <out>. Fix escaping for docproc
directives. Add support the new kernel-doc extension.]
Signed-off-by: NJonathan Corbet <corbet@lwn.net>
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Read the version and release from the top level Makefile (for use when
Sphinx is invoked directly, by e.g. Read the Docs), but override them
via Sphinx command line arguments in a normal documentation build.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Tell Sphinx where to find the extension, and pass on the kernel src tree
and kernel-doc paths to the extension.

With this, any .rst files under Documentation may contain the kernel-doc
rst directive to include kernel-doc documentation from any source file.

While building, it may be handy to pass kernel-doc extension
configuration on the command line. For example, 'make SPHINXOPTS="-D
kerneldoc_verbosity=0" htmldocs' silences all stderr output from
kernel-doc when the kernel-doc exit code is 0. (The stderr will be
logged unconditionally when the exit code is non-zero.)
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Add an extension to handle kernel-doc directives, to call kernel-doc
according to the arguments and parameters given to the reStructuredText
directive.

The syntax for the kernel-doc directive is:

.. kernel-doc:: FILENAME
   :export:
   :internal:
   :functions: FUNCTION [FUNCTION ...]
   :doc: SECTION TITLE

Of the directive options export, internal, functions, and doc, currently
only one option may be given at a time.

The FILENAME is relative from the kernel source tree root.

The extension notifies Sphinx about the document dependency on FILENAME,
causing the document to be rebuilt when the file has been changed.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The Sphinx output directory is generated.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Add basic configuration and makefile to build documentation from any
.rst files under Documentation using Sphinx. For starters, there's just
the placeholder index.rst.

At the top level Makefile, hook Sphinx documentation targets alongside
(but independent of) the DocBook toolchain, having both be run on the
various 'make *docs' targets.

All Sphinx processing is placed into Documentation/Makefile.sphinx. Both
that and the Documentation/DocBook/Makefile are now expected to handle
all the documentation targets, explicitly ignoring them if they're not
relevant for that particular toolchain. The changes to the existing
DocBook Makefile are kept minimal.

There is graceful handling of missing Sphinx and rst2pdf (which is
needed for pdf output) by checking for the tool and python module,
respectively, with informative messages to the user.

If the Read the Docs theme (sphinx_rtd_theme) is available, use it, but
otherwise gracefully fall back to the Sphinx default theme, with an
informative message to the user, and slightly less pretty HTML output.

Sphinx can now handle htmldocs, pdfdocs (if rst2pdf is available),
epubdocs and xmldocs targets. The output documents are written into per
output type subdirectories under Documentation/output.

Finally, you can pass options to sphinx-build using the SPHINXBUILD make
variable. For example, 'make SPHINXOPTS=-v htmldocs' for more verbose
output from Sphinx.

This is based on the original work by Jonathan Corbet, but he probably
wouldn't recognize this as his own anymore.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

Currently we use docproc to figure out which symbols are exported, and
then docproc calls kernel-doc on specific functions, to get
documentation on exported functions. According to git blame and docproc
comments, this is due to historical reasons, as functions and their
corresponding EXPORT_SYMBOL* may have been in different files. However
for more than ten years the recommendation in CodingStyle has been to
place the EXPORT_SYMBOL* immediately after the closing function brace
line.

Additionally, the kernel-doc comments for functions are generally placed
above the function definition in the .c files (i.e. where the
EXPORT_SYMBOL* is) rather than above the declaration in the .h
files. There are some exceptions to this, but AFAICT none of these are
included in DocBook documentation using the "!E" docproc directive.

Therefore, assuming the EXPORT_SYMBOL* and kernel-doc are with the
function definition, kernel-doc can extract the exported vs. not
information by making two passes on the input file. Add support for that
via the new -export and -internal parameters.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

I'm not quite sure why the errors below are happening, but this fixes
them.

Use of uninitialized value in string ne at ./scripts/kernel-doc line 1819, <IN> line 6494.
Use of uninitialized value $_[0] in join or string at ./scripts/kernel-doc line 1759, <IN> line 6494.
Signed-off-by: NJani Nikula <jani.nikula@intel.com>

The self-test was updated to cover zero-length strings; the function
needs to be updated, too.
Reported-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: NGeorge Spelvin <linux@sciencehorizons.net>
Fixes: fcfd2fbf ("fs/namei.c: Add hashlen_string() function")
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The original name was simply hash_string(), but that conflicted with a
function with that name in drivers/base/power/trace.c, and I decided
that calling it "hashlen_" was better anyway.

But you have to do it in two places.

[ This caused build errors for architectures that don't define
  CONFIG_DCACHE_WORD_ACCESS   - Linus ]
Signed-off-by: NGeorge Spelvin <linux@sciencehorizons.net>
Reported-by: NGuenter Roeck <linux@roeck-us.net>
Fixes: fcfd2fbf ("fs/namei.c: Add hashlen_string() function")
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The HPFS filesystem used generic_show_options to produce string that is
displayed in /proc/mounts.  However, there is a problem that the options
may disappear after remount.  If we mount the filesystem with option1
and then remount it with option2, /proc/mounts should show both option1
and option2, however it only shows option2 because the whole option
string is replaced with replace_mount_options in hpfs_remount_fs.

To fix this bug, implement the hpfs_show_options function that prints
options that are currently selected.
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit c8f33d0b ("affs: kstrdup() memory handling") checks if the
kstrdup function returns NULL due to out-of-memory condition.

However, if we are remounting a filesystem with no change to
filesystem-specific options, the parameter data is NULL.  In this case,
kstrdup returns NULL (because it was passed NULL parameter), although no
out of memory condition exists.  The mount syscall then fails with
ENOMEM.

This patch fixes the bug.  We fail with ENOMEM only if data is non-NULL.

The patch also changes the call to replace_mount_options - if we didn't
pass any filesystem-specific options, we don't call
replace_mount_options (thus we don't erase existing reported options).

Fixes: c8f33d0b ("affs: kstrdup() memory handling")
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org	# v4.1+
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit ce657611 ("hpfs: kstrdup() out of memory handling") checks if
the kstrdup function returns NULL due to out-of-memory condition.

However, if we are remounting a filesystem with no change to
filesystem-specific options, the parameter data is NULL.  In this case,
kstrdup returns NULL (because it was passed NULL parameter), although no
out of memory condition exists.  The mount syscall then fails with
ENOMEM.

This patch fixes the bug.  We fail with ENOMEM only if data is non-NULL.

The patch also changes the call to replace_mount_options - if we didn't
pass any filesystem-specific options, we don't call
replace_mount_options (thus we don't erase existing reported options).

Fixes: ce657611 ("hpfs: kstrdup() out of memory handling")
Signed-off-by: NMikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>