[PATCH 0/2] kernel-doc: Do not pre-process comments

[PATCH 0/2] kernel-doc: Do not pre-process comments

[Anna-Maria Behnsen]

Hi,

this is a repost of the RFC queue
https://lkml.kernel.org/r/20240116151456.48238-1-anna-maria@linutronix.de

Jonathan Corbet is fine with this change and mentioned in an answer the
following:

  "The kernel-doc change should really go together with the DRM change.
  I'm happy to carry both with an ack from DRMland or have the kernel-doc
  patch go through the DRM tree, whichever is easiest."

But back to the patchset: Commit 654784284430 ("kernel-doc: bugfix -
multi-line macros") introduces pre-processing of backslashes at the end of
a line to not break multi-line macros. This pre-processing is done
independently if it is inside code or inside a comment.

This illustation of a hierarchy as a code block inside a kernel-doc comment
has a backslash at the end of the line:

---8<---
/**
 * DOC: hierarchy
 *
 *                    Top Level
 *                /               \
 *         Child A                 Child B
 */
---8<---

It will be displayed as:

---8<---
	     Top Level
	 /                *        Child A                 Child B
---8<---


As I asked for a solution on the linux-doc mailing list, I got some
suggestions with workarounds and also got the suggestion by Matthew Wilcox
to adapt the backslash preprocessing in kernel-doc script. I tested it and
fixed then the newly produced warnings which are covered in the first
patch. The processing of the documentation seems to work - but please don't
rely on my tests as I'm not a perl neither a kernel-doc expert.

Thanks,

	Anna-Maria



Anna-Maria Behnsen (2):
  drm/vram-helper: Fix 'multi-line' kernel-doc comments
  scripts/kernel-doc: Do not process backslash lines in comments

 drivers/gpu/drm/drm_gem_vram_helper.c | 44 ++++++++++++---------------
 include/drm/drm_gem_vram_helper.h     | 16 +++++-----
 scripts/kernel-doc                    |  2 +-
 3 files changed, 29 insertions(+), 33 deletions(-)

-- 
2.39.2

[PATCH 1/2] drm/vram-helper: Fix 'multi-line' kernel-doc comments

[Anna-Maria Behnsen]

Reformat lines in kernel-doc comments, which make use of the backslash at
the end to suggest it is a multi-line comment. kernel-doc is able to
process e.g. the short description of a function properly, even if it is
across two lines.

No functional change.

Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
Reviewed-by: Jani Nikula <jani.nikula@intel.com>
---
 drivers/gpu/drm/drm_gem_vram_helper.c | 44 ++++++++++++---------------
 include/drm/drm_gem_vram_helper.h     | 16 +++++-----
 2 files changed, 28 insertions(+), 32 deletions(-)

diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c
index b67eafa55715..b7d42210fccc 100644
--- a/drivers/gpu/drm/drm_gem_vram_helper.c
+++ b/drivers/gpu/drm/drm_gem_vram_helper.c
@@ -260,8 +260,7 @@ static u64 drm_gem_vram_pg_offset(struct drm_gem_vram_object *gbo)
 }
 
 /**
- * drm_gem_vram_offset() - \
-	Returns a GEM VRAM object's offset in video memory
+ * drm_gem_vram_offset() - Returns a GEM VRAM object's offset in video memory
  * @gbo:	the GEM VRAM object
  *
  * This function returns the buffer object's offset in the device's video
@@ -470,14 +469,15 @@ void drm_gem_vram_vunmap(struct drm_gem_vram_object *gbo,
 EXPORT_SYMBOL(drm_gem_vram_vunmap);
 
 /**
- * drm_gem_vram_fill_create_dumb() - \
-	Helper for implementing &struct drm_driver.dumb_create
+ * drm_gem_vram_fill_create_dumb() - Helper for implementing
+ *				     &struct drm_driver.dumb_create
+ *
  * @file:		the DRM file
  * @dev:		the DRM device
  * @pg_align:		the buffer's alignment in multiples of the page size
  * @pitch_align:	the scanline's alignment in powers of 2
- * @args:		the arguments as provided to \
-				&struct drm_driver.dumb_create
+ * @args:		the arguments as provided to
+ *			&struct drm_driver.dumb_create
  *
  * This helper function fills &struct drm_mode_create_dumb, which is used
  * by &struct drm_driver.dumb_create. Implementations of this interface
@@ -575,8 +575,7 @@ static int drm_gem_vram_bo_driver_move(struct drm_gem_vram_object *gbo,
  */
 
 /**
- * drm_gem_vram_object_free() - \
-	Implements &struct drm_gem_object_funcs.free
+ * drm_gem_vram_object_free() - Implements &struct drm_gem_object_funcs.free
  * @gem:       GEM object. Refers to &struct drm_gem_vram_object.gem
  */
 static void drm_gem_vram_object_free(struct drm_gem_object *gem)
@@ -591,12 +590,11 @@ static void drm_gem_vram_object_free(struct drm_gem_object *gem)
  */
 
 /**
- * drm_gem_vram_driver_dumb_create() - \
-	Implements &struct drm_driver.dumb_create
+ * drm_gem_vram_driver_dumb_create() - Implements &struct drm_driver.dumb_create
  * @file:		the DRM file
  * @dev:		the DRM device
- * @args:		the arguments as provided to \
-				&struct drm_driver.dumb_create
+ * @args:		the arguments as provided to
+ *			&struct drm_driver.dumb_create
  *
  * This function requires the driver to use @drm_device.vram_mm for its
  * instance of VRAM MM.
@@ -639,8 +637,8 @@ static void __drm_gem_vram_plane_helper_cleanup_fb(struct drm_plane *plane,
 }
 
 /**
- * drm_gem_vram_plane_helper_prepare_fb() - \
- *	Implements &struct drm_plane_helper_funcs.prepare_fb
+ * drm_gem_vram_plane_helper_prepare_fb() - Implements &struct
+ *					    drm_plane_helper_funcs.prepare_fb
  * @plane:	a DRM plane
  * @new_state:	the plane's new state
  *
@@ -690,8 +688,8 @@ drm_gem_vram_plane_helper_prepare_fb(struct drm_plane *plane,
 EXPORT_SYMBOL(drm_gem_vram_plane_helper_prepare_fb);
 
 /**
- * drm_gem_vram_plane_helper_cleanup_fb() - \
- *	Implements &struct drm_plane_helper_funcs.cleanup_fb
+ * drm_gem_vram_plane_helper_cleanup_fb() - Implements &struct
+ *					    drm_plane_helper_funcs.cleanup_fb
  * @plane:	a DRM plane
  * @old_state:	the plane's old state
  *
@@ -717,8 +715,8 @@ EXPORT_SYMBOL(drm_gem_vram_plane_helper_cleanup_fb);
  */
 
 /**
- * drm_gem_vram_simple_display_pipe_prepare_fb() - \
- *	Implements &struct drm_simple_display_pipe_funcs.prepare_fb
+ * drm_gem_vram_simple_display_pipe_prepare_fb() - Implements &struct
+ *				   drm_simple_display_pipe_funcs.prepare_fb
  * @pipe:	a simple display pipe
  * @new_state:	the plane's new state
  *
@@ -739,8 +737,8 @@ int drm_gem_vram_simple_display_pipe_prepare_fb(
 EXPORT_SYMBOL(drm_gem_vram_simple_display_pipe_prepare_fb);
 
 /**
- * drm_gem_vram_simple_display_pipe_cleanup_fb() - \
- *	Implements &struct drm_simple_display_pipe_funcs.cleanup_fb
+ * drm_gem_vram_simple_display_pipe_cleanup_fb() - Implements &struct
+ *						   drm_simple_display_pipe_funcs.cleanup_fb
  * @pipe:	a simple display pipe
  * @old_state:	the plane's old state
  *
@@ -761,8 +759,7 @@ EXPORT_SYMBOL(drm_gem_vram_simple_display_pipe_cleanup_fb);
  */
 
 /**
- * drm_gem_vram_object_pin() - \
-	Implements &struct drm_gem_object_funcs.pin
+ * drm_gem_vram_object_pin() - Implements &struct drm_gem_object_funcs.pin
  * @gem:	The GEM object to pin
  *
  * Returns:
@@ -785,8 +782,7 @@ static int drm_gem_vram_object_pin(struct drm_gem_object *gem)
 }
 
 /**
- * drm_gem_vram_object_unpin() - \
-	Implements &struct drm_gem_object_funcs.unpin
+ * drm_gem_vram_object_unpin() - Implements &struct drm_gem_object_funcs.unpin
  * @gem:	The GEM object to unpin
  */
 static void drm_gem_vram_object_unpin(struct drm_gem_object *gem)
diff --git a/include/drm/drm_gem_vram_helper.h b/include/drm/drm_gem_vram_helper.h
index e18429f09e53..2938ba80750d 100644
--- a/include/drm/drm_gem_vram_helper.h
+++ b/include/drm/drm_gem_vram_helper.h
@@ -33,8 +33,8 @@ struct vm_area_struct;
  * struct drm_gem_vram_object - GEM object backed by VRAM
  * @bo:		TTM buffer object
  * @map:	Mapping information for @bo
- * @placement:	TTM placement information. Supported placements are \
-	%TTM_PL_VRAM and %TTM_PL_SYSTEM
+ * @placement:	TTM placement information. Supported placements are %TTM_PL_VRAM
+ *		and %TTM_PL_SYSTEM
  * @placements:	TTM placement information.
  *
  * The type struct drm_gem_vram_object represents a GEM object that is
@@ -126,8 +126,8 @@ drm_gem_vram_plane_helper_cleanup_fb(struct drm_plane *plane,
 				     struct drm_plane_state *old_state);
 
 /**
- * DRM_GEM_VRAM_PLANE_HELPER_FUNCS -
- *	Initializes struct drm_plane_helper_funcs for VRAM handling
+ * DRM_GEM_VRAM_PLANE_HELPER_FUNCS - Initializes struct drm_plane_helper_funcs
+ *				     for VRAM handling
  *
  * Drivers may use GEM BOs as VRAM helpers for the framebuffer memory. This
  * macro initializes struct drm_plane_helper_funcs to use the respective helper
@@ -150,8 +150,8 @@ void drm_gem_vram_simple_display_pipe_cleanup_fb(
 	struct drm_plane_state *old_state);
 
 /**
- * define DRM_GEM_VRAM_DRIVER - default callback functions for \
-	&struct drm_driver
+ * define DRM_GEM_VRAM_DRIVER - default callback functions for
+ *				&struct drm_driver
  *
  * Drivers that use VRAM MM and GEM VRAM can use this macro to initialize
  * &struct drm_driver with default functions.
@@ -185,8 +185,8 @@ struct drm_vram_mm {
 };
 
 /**
- * drm_vram_mm_of_bdev() - \
-	Returns the container of type &struct ttm_device for field bdev.
+ * drm_vram_mm_of_bdev() - Returns the container of type &struct ttm_device for
+ *			   field bdev.
  * @bdev:	the TTM BO device
  *
  * Returns:
-- 
2.39.2

[PATCH 2/2] scripts/kernel-doc: Do not process backslash lines in comments

[Anna-Maria Behnsen]

Commit 654784284430 ("kernel-doc: bugfix - multi-line macros") introduces
pre-processing of backslashes at the end of a line to not break multi-line
macros. This pre-processing is done independently if it is inside code or
inside a comment.

This illustation of a hierarchy as a code block inside a kernel-doc comment
has a backslash at the end of the line:

---8<---
/**
 * DOC: hierarchy
 *
 *                    Top Level
 *                /               \
 *         Child A                 Child B
 */
---8<---

It will be displayed as:

---8<---
	     Top Level
	 /                *        Child A                 Child B
---8<---

To prevent this, do the pre-processing only for lines which are no
comments, e.g. do not start with ' *'.

Suggested-by: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>
---
 scripts/kernel-doc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/kernel-doc b/scripts/kernel-doc
index e8aefd258a29..4277af79de86 100755
--- a/scripts/kernel-doc
+++ b/scripts/kernel-doc
@@ -2331,7 +2331,7 @@ sub process_file($) {
 
     $section_counter = 0;
     while (<IN_FILE>) {
-	while (s/\\\s*$//) {
+	while (!/^ \*/ && s/\\\s*$//) {
 	    $_ .= <IN_FILE>;
 	}
 	# Replace tabs by spaces
-- 
2.39.2

Re: [PATCH 2/2] scripts/kernel-doc: Do not process backslash lines in comments

[Randy Dunlap]

On 1/22/24 01:31, Anna-Maria Behnsen wrote:
> Commit 654784284430 ("kernel-doc: bugfix - multi-line macros") introduces
> pre-processing of backslashes at the end of a line to not break multi-line
> macros. This pre-processing is done independently if it is inside code or
> inside a comment.
> 
> This illustation of a hierarchy as a code block inside a kernel-doc comment
> has a backslash at the end of the line:
> 
> ---8<---
> /**
>  * DOC: hierarchy
>  *
>  *                    Top Level
>  *                /               \
>  *         Child A                 Child B
>  */
> ---8<---
> 
> It will be displayed as:
> 
> ---8<---
> 	     Top Level
> 	 /                *        Child A                 Child B
> ---8<---
> 
> To prevent this, do the pre-processing only for lines which are no
> comments, e.g. do not start with ' *'.
> 
> Suggested-by: Matthew Wilcox <willy@infradead.org>
> Signed-off-by: Anna-Maria Behnsen <anna-maria@linutronix.de>

I compared several hundred html files before and after this patch
and they were all the same, so I will say:

Tested-by: Randy Dunlap <rdunlap@infradead.org>

Thanks.

> ---
>  scripts/kernel-doc | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/scripts/kernel-doc b/scripts/kernel-doc
> index e8aefd258a29..4277af79de86 100755
> --- a/scripts/kernel-doc
> +++ b/scripts/kernel-doc
> @@ -2331,7 +2331,7 @@ sub process_file($) {
>  
>      $section_counter = 0;
>      while (<IN_FILE>) {
> -	while (s/\\\s*$//) {
> +	while (!/^ \*/ && s/\\\s*$//) {
>  	    $_ .= <IN_FILE>;
>  	}
>  	# Replace tabs by spaces

-- 
#Randy

Re: [PATCH 0/2] kernel-doc: Do not pre-process comments

[Daniel Vetter]

On Mon, Jan 22, 2024 at 10:31:50AM +0100, Anna-Maria Behnsen wrote:
> Hi,
> 
> this is a repost of the RFC queue
> https://lkml.kernel.org/r/20240116151456.48238-1-anna-maria@linutronix.de
> 
> Jonathan Corbet is fine with this change and mentioned in an answer the
> following:
> 
>   "The kernel-doc change should really go together with the DRM change.
>   I'm happy to carry both with an ack from DRMland or have the kernel-doc
>   patch go through the DRM tree, whichever is easiest."

Agree, that sounds like the simplest merge plan and I don't think we have
anything in-flight for vram helpers that would cause conflicts. For
merging the drm patch through Jon's -doc tree:

Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> 
> But back to the patchset: Commit 654784284430 ("kernel-doc: bugfix -
> multi-line macros") introduces pre-processing of backslashes at the end of
> a line to not break multi-line macros. This pre-processing is done
> independently if it is inside code or inside a comment.
> 
> This illustation of a hierarchy as a code block inside a kernel-doc comment
> has a backslash at the end of the line:
> 
> ---8<---
> /**
>  * DOC: hierarchy
>  *
>  *                    Top Level
>  *                /               \
>  *         Child A                 Child B
>  */
> ---8<---
> 
> It will be displayed as:
> 
> ---8<---
> 	     Top Level
> 	 /                *        Child A                 Child B
> ---8<---
> 
> 
> As I asked for a solution on the linux-doc mailing list, I got some
> suggestions with workarounds and also got the suggestion by Matthew Wilcox
> to adapt the backslash preprocessing in kernel-doc script. I tested it and
> fixed then the newly produced warnings which are covered in the first
> patch. The processing of the documentation seems to work - but please don't
> rely on my tests as I'm not a perl neither a kernel-doc expert.
> 
> Thanks,
> 
> 	Anna-Maria
> 
> 
> 
> Anna-Maria Behnsen (2):
>   drm/vram-helper: Fix 'multi-line' kernel-doc comments
>   scripts/kernel-doc: Do not process backslash lines in comments
> 
>  drivers/gpu/drm/drm_gem_vram_helper.c | 44 ++++++++++++---------------
>  include/drm/drm_gem_vram_helper.h     | 16 +++++-----
>  scripts/kernel-doc                    |  2 +-
>  3 files changed, 29 insertions(+), 33 deletions(-)
> 
> -- 
> 2.39.2
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

Re: [PATCH 0/2] kernel-doc: Do not pre-process comments

[Jonathan Corbet]

Anna-Maria Behnsen <anna-maria@linutronix.de> writes:

> Hi,
>
> this is a repost of the RFC queue
> https://lkml.kernel.org/r/20240116151456.48238-1-anna-maria@linutronix.de
>
> Jonathan Corbet is fine with this change and mentioned in an answer the
> following:
>
>   "The kernel-doc change should really go together with the DRM change.
>   I'm happy to carry both with an ack from DRMland or have the kernel-doc
>   patch go through the DRM tree, whichever is easiest."
>
> But back to the patchset: Commit 654784284430 ("kernel-doc: bugfix -
> multi-line macros") introduces pre-processing of backslashes at the end of
> a line to not break multi-line macros. This pre-processing is done
> independently if it is inside code or inside a comment.
>
> This illustation of a hierarchy as a code block inside a kernel-doc comment
> has a backslash at the end of the line:
>
> ---8<---
> /**
>  * DOC: hierarchy
>  *
>  *                    Top Level
>  *                /               \
>  *         Child A                 Child B
>  */
> ---8<---
>
> It will be displayed as:
>
> ---8<---
> 	     Top Level
> 	 /                *        Child A                 Child B
> ---8<---
>
>
> As I asked for a solution on the linux-doc mailing list, I got some
> suggestions with workarounds and also got the suggestion by Matthew Wilcox
> to adapt the backslash preprocessing in kernel-doc script. I tested it and
> fixed then the newly produced warnings which are covered in the first
> patch. The processing of the documentation seems to work - but please don't
> rely on my tests as I'm not a perl neither a kernel-doc expert.
>
> Thanks,
>
> 	Anna-Maria
>
>
>
> Anna-Maria Behnsen (2):
>   drm/vram-helper: Fix 'multi-line' kernel-doc comments
>   scripts/kernel-doc: Do not process backslash lines in comments
>
>  drivers/gpu/drm/drm_gem_vram_helper.c | 44 ++++++++++++---------------
>  include/drm/drm_gem_vram_helper.h     | 16 +++++-----
>  scripts/kernel-doc                    |  2 +-
>  3 files changed, 29 insertions(+), 33 deletions(-)

Series applied, thanks.

jon