As reported by Sphinx:

	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:1147: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_oa_wait_unlocked'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:1169: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_oa_poll_wait'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:1189: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_oa_read'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:2669: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_oa_stream_enable'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:2734: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_oa_stream_disable'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:2820: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_oa_stream_init'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3010: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_read'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3098: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_poll_locked'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3129: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_poll'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3152: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_enable_locked'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3181: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_disable_locked'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3273: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_ioctl'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3296: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_destroy_locked'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3321: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_release'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3379: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_open_ioctl_locked'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3534: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'read_properties_unlocked'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3717: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_open_ioctl'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3760: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_register'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:3789: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_unregister'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:4009: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_add_config_ioctl'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:4162: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_remove_config_ioctl'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:4260: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_init'.
	./Documentation/gpu/i915:646: ./drivers/gpu/drm/i915/i915_perf.c:4423: WARNING: Duplicate C declaration, also defined in 'gpu/i915'.
	Declaration is 'i915_perf_fini'.

With Sphinx 3, C declarations can't be duplicated anymore,
so let's exclude those from the other internals found on
i915_perf.c file.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Those are already documented at:

	Documentation/driver-api/firmware/request_firmware.rst

Including it twice is causing lots of warnings:

	./Documentation/driver-api/infrastructure.rst: WARNING: Duplicate C declaration, also defined in 'driver-api/firmware/request_firmware'.
	Declaration is 'request_firmware'.
	./Documentation/driver-api/infrastructure.rst: WARNING: Duplicate C declaration, also defined in 'driver-api/firmware/request_firmware'.
	Declaration is 'firmware_request_nowarn'.
	./Documentation/driver-api/infrastructure.rst: WARNING: Duplicate C declaration, also defined in 'driver-api/firmware/request_firmware'.
	Declaration is 'request_firmware_direct'.
	./Documentation/driver-api/infrastructure.rst: WARNING: Duplicate C declaration, also defined in 'driver-api/firmware/request_firmware'.
	Declaration is 'firmware_request_platform'.
	./Documentation/driver-api/infrastructure.rst: WARNING: Duplicate C declaration, also defined in 'driver-api/firmware/request_firmware'.
	Declaration is 'firmware_request_cache'.
	./Documentation/driver-api/infrastructure.rst: WARNING: Duplicate C declaration, also defined in 'driver-api/firmware/request_firmware'.
	Declaration is 'request_firmware_into_buf'.
	./Documentation/driver-api/infrastructure.rst: WARNING: Duplicate C declaration, also defined in 'driver-api/firmware/request_firmware'.
	Declaration is 'request_firmware_nowait'.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

The usage of :c:type: to reference to a struct member is wrong,
as pointed by Sphinx 3:

	./Documentation/driver-api/libata.rst:511: WARNING: Unparseable C cross-reference: 'qc->complete_fn'
	Invalid C declaration: Expected end of definition. [error at 2]
	  qc->complete_fn
	  --^

Instead, let's use :c:expr: for such purpose.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Which Sphinx 3, :c:type:  can't be used anymore for structs,
as this should be used only for typedefs.

Rely on automarkup.py for struct references.

This file has an special case, though: it uses the tag also
to point to an array. Let's use, instead, :c:expr: for such
purpose, as it should do the right thing.

This should fix this warning:

	./Documentation/dev-tools/kgdb.rst:875: WARNING: Unparseable C cross-reference: 'kdb_poll_funcs[]'
	Invalid C declaration: Expected end of definition. [error at 14]
	  kdb_poll_funcs[]
	  --------------^
Acked-by: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Those macros are not doing the right thing with Sphinx 3,
causing parse errors:

	./Documentation/driver-api/fpga/fpga-mgr.rst:104: WARNING: Unparseable C cross-reference: 'fpga_manager->state'
	Invalid C declaration: Expected end of definition. [error at 12]
	  fpga_manager->state
	  ------------^
	./Documentation/driver-api/fpga/fpga-programming.rst:18: WARNING: Unparseable C cross-reference: 'fpga_region->info'
	Invalid C declaration: Expected end of definition. [error at 11]
	  fpga_region->info
	  -----------^
	./Documentation/driver-api/fpga/fpga-region.rst:62: WARNING: Unparseable C cross-reference: 'fpga_region->bridge_list'
	Invalid C declaration: Expected end of definition. [error at 11]
	  fpga_region->bridge_list
	  -----------^
	./Documentation/driver-api/fpga/fpga-region.rst:62: WARNING: Unparseable C cross-reference: 'fpga_region->get_bridges'
	Invalid C declaration: Expected end of definition. [error at 11]
	  fpga_region->get_bridges
	  -----------^

Replace them by :c:expr:, with does what's desired.
Reviewed-by: Moritz Fischer <mdf@kernel.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Some such markups are invalid, as reported by Sphinx:

	./Documentation/sound/kernel-api/writing-an-alsa-driver.rst:3317: WARNING: Unparseable C cross-reference: 'snd_rawmidi_transmit*'
	Invalid C declaration: Expected end of definition. [error at 20]
	  snd_rawmidi_transmit*
	  --------------------^
	./Documentation/sound/kernel-api/writing-an-alsa-driver.rst:3917: WARNING: Unparseable C cross-reference: 'copy_from/to_user'
	Invalid C declaration: Expected end of definition. [error at 9]
	  copy_from/to_user
	  ---------^

The first case seems to be better replaced by a literal.

For the second one, let's generate cross-references, by
spliting it in two.
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

The :c:type macros are not used properly there, as reported
by Sphinx 3:

	./Documentation/block/blk-mq.rst:112: WARNING: Unparseable C cross-reference: 'hctx->dispatch'
	Invalid C declaration: Expected end of definition. [error at 4]
	  hctx->dispatch
	  ----^

Also, they won't be generating any cross references.

So, replace them by a literal markup.
Reviewed-by: André Almeida <andrealmeid@collabora.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

the :c:type shouldn't be used with structs with Sphinx 3,
as the C domain there uses .. c:struct for structs.

As we have the automarkup extension, let's just get rid of
all :c:type as a whole, as those will be automagically
marked as such.

This solves a bunch of warnings with Sphinx 3, like those:

	.../Documentation/sound/kernel-api/writing-an-alsa-driver.rst:490: WARNING: Unparseable C cross-reference: 'calling snd_card_free'
	Invalid C declaration: Expected end of definition. [error at 8]
	  calling snd_card_free
	  --------^
	.../Documentation/sound/kernel-api/writing-an-alsa-driver.rst:3328: WARNING: Unparseable C cross-reference: 'snd_rawmidi_transmit*'
	Invalid C declaration: Expected end of definition. [error at 20]
	  snd_rawmidi_transmit*
	  --------------------^
	.../Documentation/sound/kernel-api/writing-an-alsa-driver.rst:3928: WARNING: Unparseable C cross-reference: 'copy_from/to_user'
	Invalid C declaration: Expected end of definition. [error at 9]
	  copy_from/to_user
	  ---------^
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

There's no need to use macros to use :c:type on this file,
as automarkup.py should do this automatically.

Also, this breaks compatibility with Sphinx 3.x, as there,
structs should be declared using .. c:struct.

So, get rid of them.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

The :c:type: tag has problems with Sphinx 3.x, as structs
there should be declared with c:struct.

So, remove them, relying at automarkup.py extension to
convert them into cross-references.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

There is currently a problem with kernel-doc tags from blk.c:

	.../Documentation/admin-guide/pstore-blk:239: ./fs/pstore/blk.c:175: WARNING: Duplicate C declaration, also defined in 'admin-guide/pstore-blk'.
	Declaration is 'register_pstore_device'.
	.../Documentation/admin-guide/pstore-blk:239: ./fs/pstore/blk.c:432: WARNING: Duplicate C declaration, also defined in 'admin-guide/pstore-blk'.
	Declaration is 'register_pstore_blk'.
	.../Documentation/admin-guide/pstore-blk:242: ./include/linux/pstore_blk.h:43: WARNING: Duplicate C declaration, also defined in 'admin-guide/pstore-blk'.
	Declaration is 'pstore_device_info'.

Basically, the internal parts is shown with :export:, instead
of :internal:. Yet, there are some other exported docs that
aren't at the document, because they lack :identifiers:.

So, instead, let's just use :export: at the kAPI part of
the documentation.
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Those are already defined at kernel-api.rst, as part of the
synchronization primitives chapter.

This solves several Sphinx 3 warnings, like:

	.../Documentation/driver-api/basics.rst: WARNING: Duplicate C declaration, also defined in 'core-api/kernel-api'.
	Declaration is 'rcu_idle_enter'.
	.../Documentation/driver-api/basics.rst: WARNING: Duplicate C declaration, also defined in 'core-api/kernel-api'.
	Declaration is 'rcu_idle_exit'.
	.../Documentation/driver-api/basics.rst: WARNING: Duplicate C declaration, also defined in 'core-api/kernel-api'.
	Declaration is 'rcu_is_watching'.
	.../Documentation/driver-api/basics.rst: WARNING: Duplicate C declaration, also defined in 'core-api/kernel-api'.
	Declaration is 'call_rcu'.
	.../Documentation/driver-api/basics.rst: WARNING: Duplicate C declaration, also defined in 'core-api/kernel-api'.
	Declaration is 'synchronize_rcu'.
	...
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

The infrastructure.rst file already includes the external
symbols from drivers/base/core.c.

Duplicating 3 functions there causes namespace collisions:

	Documentation/driver-api/device_link.rst: WARNING: Duplicate C declaration, also defined in 'driver-api/infrastructure'.
	Declaration is 'device_link_state'.
	Documentation/driver-api/device_link.rst: WARNING: Duplicate C declaration, also defined in 'driver-api/infrastructure'.
	Declaration is 'device_link_add'.
	Documentation/driver-api/device_link.rst: WARNING: Duplicate C declaration, also defined in 'driver-api/infrastructure'.
	Declaration is 'device_link_del'.
	Documentation/driver-api/device_link.rst: WARNING: Duplicate C declaration, also defined in 'driver-api/infrastructure'.
	Declaration is 'device_link_remove'.

So, drop the reference, adding just a mention to the functions
associated with device_link.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

This is already included at scsi.rst. So, remove the duplication,
in order to avoid Sphinx warnings.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

As there's already a rst file with workqueue markups, containing
part of them, move the other definitions, in order to avoid
warnings with Sphinx.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

The sound API is documented on two different parts:
under Documentation/driver-api/sound.rst and under
Documentation/sound/kernel-api/alsa-driver-api.rst.

The alsa-driver-api.rst seems more complete, and APIs
are split per type. There's just one missing kernel-doc
markup there.

Add it and drop the duplicated one.
Reviewed-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

This is already included at genericirq.rst. Adding it twice
causes C namespace duplication:

	.../Documentation/core-api/kernel-api:237: ../kernel/irq/manage.c:100: WARNING: Duplicate C declaration, also defined in 'genericirq'.
	Declaration is 'synchronize_hardirq'.
	.../Documentation/core-api/kernel-api:237: ../kernel/irq/manage.c:128: WARNING: Duplicate C declaration, also defined in 'genericirq'.
	Declaration is 'synchronize_irq'.
	.../Documentation/core-api/kernel-api:237: ../kernel/irq/manage.c:443: WARNING: Duplicate C declaration, also defined in 'genericirq'.
	Declaration is 'irq_set_affinity_notifier'.
	...
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Currently, kernel/irq/chip.c is included twice, one for
export functions, and then for internal ones. However, as
the :export:  and :internal: tags are missing, they ended
being included twice.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

There are some warnings produced with Sphinx 3.x:

	Documentation/networking/ieee802154.rst:29: WARNING: Error in declarator or parameters
	Invalid C declaration: Expecting "(" in parameters. [error at 7]
	  int sd = socket(PF_IEEE802154, SOCK_DGRAM, 0);
	  -------^
	Documentation/networking/ieee802154.rst:134: WARNING: Invalid C declaration: Expected end of definition. [error at 81]
	  void ieee802154_rx_irqsafe(struct ieee802154_hw *hw, struct sk_buff *skb, u8 lqi):
	  ---------------------------------------------------------------------------------^
	Documentation/networking/ieee802154.rst:139: WARNING: Invalid C declaration: Expected end of definition. [error at 95]
	  void ieee802154_xmit_complete(struct ieee802154_hw *hw, struct sk_buff *skb, bool ifs_handling):
	  -----------------------------------------------------------------------------------------------^
	Documentation/networking/ieee802154.rst:158: WARNING: Invalid C declaration: Expected end of definition. [error at 35]
	  int start(struct ieee802154_hw *hw):
	  -----------------------------------^
	Documentation/networking/ieee802154.rst:162: WARNING: Invalid C declaration: Expected end of definition. [error at 35]
	  void stop(struct ieee802154_hw *hw):
	  -----------------------------------^
	Documentation/networking/ieee802154.rst:166: WARNING: Invalid C declaration: Expected end of definition. [error at 61]
	  int xmit_async(struct ieee802154_hw *hw, struct sk_buff *skb):
	  -------------------------------------------------------------^
	Documentation/networking/ieee802154.rst:171: WARNING: Invalid C declaration: Expected end of definition. [error at 43]
	  int ed(struct ieee802154_hw *hw, u8 *level):
	  -------------------------------------------^
	Documentation/networking/ieee802154.rst:176: WARNING: Invalid C declaration: Expected end of definition. [error at 62]
	  int set_channel(struct ieee802154_hw *hw, u8 page, u8 channel):
	  --------------------------------------------------------------^

Caused by some bad c:function: prototypes. Fix them.
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

The C domain functions there collide with the English ones,
due to namespace collision, generating lots of warnings with
Sphinx 3.x:

	./include/linux/mutex.h:121: WARNING: Duplicate C declaration, also defined in 'translations/it_IT/kernel-hacking/locking'.
	Declaration is 'mutex_init'.
	./include/linux/mutex.h:152: WARNING: Duplicate C declaration, also defined in 'translations/it_IT/kernel-hacking/locking'.
	Declaration is 'mutex_is_locked'.
	./include/linux/mutex.h:226: WARNING: Duplicate C declaration, also defined in 'translations/it_IT/kernel-hacking/locking'.
	Declaration is 'mutex_trylock_recursive'.
	./kernel/locking/mutex.c:281: WARNING: Duplicate C declaration, also defined in 'translations/it_IT/kernel-hacking/locking'.
	Declaration is 'mutex_lock'.
	...

Add a namespace tag there, in order to prevent that.
Acked-by: Federico Vaga <federico.vaga@vaga.pv.it>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

There are some c-domain tags that are wrong. While this won't
cause problems with Sphinx < 3.0, this cause troubles with
newer versions, as the C parser won't recognize the contents
of the tag, and will drop it from the output.

Let's just place them at literal blocks.
Reviewed-by: Kamalesh Babulal <kamalesh@linux.vnet.ibm.com>
Acked-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

The :c:type:`foo` only works properly with structs before
Sphinx 3.x.

On Sphinx 3.x, structs should now be declared using the
.. c:struct, and referenced via :c:struct tag.

As we now have the automarkup.py macro, that automatically
convert:
	struct foo

into cross-references, let's get rid of that, solving
several warnings when building docs with Sphinx 3.x.

Reviewed-by: André Almeida <andrealmeid@collabora.com> # blk-mq.rst
Reviewed-by: Takashi Iwai <tiwai@suse.de> # sound
Reviewed-by: Mike Rapoport <rppt@linux.ibm.com>
Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

There are three files with replace macros for structs,
mapping them into Sphinx 2.x C domain references.

Well, this is broken on Sphinx 3.x. Also, for Sphinx 2.x,
the automarkup macro should be able to take care of them.

So, let's just drop those.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

The new C domain code on Sphinx 3 doesn't allow anymore
to use c:type:: for structs.

Now that cdomain.py has backward support, let's use
c:struct:: instead.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Sphinx 3.x broke support for the cdomain.py extension, as the
c domain code was rewritten. Due to that, the c tags need to
be re-written, in order to use the new c domain notation.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Sphinx 3.x broke support for the cdomain.py extension, as the
c domain code was rewritten. Due to that, the c tags need to
be re-written, in order to use the new c domain notation.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Sphinx 3.x broke support for the cdomain.py extension, as the
c domain code was rewritten. Due to that, the c tags need to
be re-written, in order to use the new c domain notation.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Sphinx 3.x broke support for the cdomain.py extension, as the
c domain code was rewritten. Due to that, the c tags need to
be re-written, in order to use the new c domain notation.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Sphinx 3.x broke support for the cdomain.py extension, as the
c domain code was rewritten. Due to that, the c tags need to
be re-written, in order to use the new c domain notation.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Sphinx 3 added support for declaring C macros with parameters using the
:c:macro role.

To support automarkup for both functions and parametrized macros using
the same regex (words ending in ()), try to cross-reference to both, and
only fall back to regular text if neither exist.
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@protonmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

With the transition to Sphinx 3, new warnings were caused by
automarkup, exposing bugs in the name matching.

When automarkup parsed a text like "struct struct" in the documentation,
it tried to cross-reference to a "struct" symbol, which is recognized as
a C reserved word by Sphinx 3, generating a warning.

Add some C reserved words (only the ones that were causing warnings) to
a list and skip them while trying to cross-reference.
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@protonmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

With the transition to Sphinx 3, new warnings were generated by
automarkup, exposing bugs in the regexes.

The warnings were caused by the expressions matching words in the
translated versions of the documentation, since any unicode character
was matched.

Fix the regular expression by making the C regexes use ASCII and
ensuring the expressions only match the beginning of words,
in order to avoid warnings like this:

	WARNING: Unparseable C cross-reference: '调用debugfs_rename'

That's probably due to the lack of using spaces between words
on Chinese.
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@protonmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

While Sphinx 2 used a single c:type role for struct, union, enum and
typedef, Sphinx 3 uses a specific role for each one.
To keep backward compatibility, detect the Sphinx version and use the
correct roles for that version.
Signed-off-by: Nícolas F. R. A. Prado <nfraprado@protonmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Currently, there's no way to exclude identifiers from
a kernel-doc markup. Add support for it.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Finding where an error like this was generated:
	../lib/math/div64.c:73: WARNING: Duplicate C declaration, also defined in 'kernel-api'.

Can take some time, as there's no glue about what kernel-doc
tag generated it. It is a way better to display it as:

	.../Documentation/core-api/kernel-api:171: ../lib/math/div64.c:73: WARNING: Duplicate C declaration, also defined in 'kernel-api'.
	Declaration is 'div_s64_rem'.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

While most of the C domain parsing is done via kernel-doc,
some RST files use C domain tags directly.

While several of them can be removed for Sphinx < 3.0, due
to automarkup.py, and several others that could be
converted into kernel-doc markups, changes like that are
time-consuming, and may not fit all cases.

As we already have the cdomain.py for handing backward
compatibility with Sphinx versions below 3.0, let's
make it more complete, in order to cover any usage of the
newer tags outside kernel-doc.

This way, it should be feasible to use the new tags inside
the Kernel tree, without losing backward compatibility.

This should allow fixing the remaining warnings with
the Kernel tags.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Since Sphinx 3.0, the C domain code was rewritten, but only
after version 3.1 it got support for setting namespaces on
C domains, with is something that it is required, in order to
document system calls, like ioctl() and others.

As part of changing the documentation subsystem to properly
build with Sphinx 3.1+, add support for such new tag:

	.. c:namespace::"

Such tag optionally replaces the optional "name" tag for functions,
setting a single namespace domain for all C references found
at the file.

With that, it should be possible to convert existing
documentation to be compatible with both Sphinx 1.x/2.x and
3.1+.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

There are a few namespace clashes by using c:macro everywhere:

basically, when using it, we can't have something like:

	.. c:struct:: pwm_capture

	.. c:macro:: pwm_capture

So, we need to use, instead:

	.. c:function:: int pwm_capture (struct pwm_device * pwm, struct pwm_capture * result, unsigned long timeout)

for the function declaration.

The kernel-doc change was proposed by Jakob Lykke Andersen here:

	https://github.com/jakobandersen/linux_docs/commit/6fd2076ec001cca7466857493cd678df4dfe4a65

Although I did a different implementation.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

Address several issues related to pointing to the wrong line
number:

1) ensure that line numbers will always be initialized

   When section is the default (Description), the line number
   is not initializing, producing this:

	$ ./scripts/kernel-doc --enable-lineno ./drivers/media/v4l2-core/v4l2-mem2mem.c|less

	**Description**

	#define LINENO 0
	In case of streamoff or release called on any context,
	1] If the context is currently running, then abort job will be called
	2] If the context is queued, then the context will be removed from
	   the job_queue

  Which is not right. Ensure that the line number will always
  be there. After applied, the result now points to the right location:

	**Description**

	#define LINENO 410
	In case of streamoff or release called on any context,
	1] If the context is currently running, then abort job will be called
	2] If the context is queued, then the context will be removed from
	   the job_queue

2) The line numbers for function prototypes are always + 1,
   because it is taken at the line after handling the prototype.
   Change the logic to point to the next line after the /** */
   block;

3) The "DOC:" line number should point to the same line as this
   markup is found, and not to the next one.

Probably part of the issues were due to a but that was causing
the line number offset to be incremented by one, if --export
were used.
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

When kernel-doc is called via kerneldoc.py, there's no need to
auto-detect the Sphinx version, as the Sphinx module already
knows it. So, add an optional parameter to allow changing the
Sphinx dialect.

As kernel-doc can also be manually called, keep the auto-detection
logic if the parameter was not specified. On such case, emit
a warning if sphinx-build can't be found at PATH.

I ended using a suggestion from Joe for using a more readable
regex, instead of using a complex one with a hidden group like:

	m/^(\d+)\.(\d+)(?:\.?(\d+)?)/

in order to get the optional <patch> argument.

Thanks-to: Joe Perches <joe@perches.com>
Suggested-by: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>