linux-kernel - Re: [PATCH drm-misc-next v5 1/4] drm/fb: rename FB CMA helpers to FB DMA helpers

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Message-ID: <Ytg596Lk4kumqeRD@ravnborg.org>
Date:   Wed, 20 Jul 2022 19:23:03 +0200
From:   Sam Ravnborg <sam@...nborg.org>
To:     Danilo Krummrich <dakr@...hat.com>
Cc:     daniel@...ll.ch, laurent.pinchart@...asonboard.com,
        airlied@...ux.ie, tzimmermann@...e.de, mripard@...nel.org,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org
Subject: Re: [PATCH drm-misc-next v5 1/4] drm/fb: rename FB CMA helpers to FB
 DMA helpers

Hi Danilo,

On Wed, Jul 20, 2022 at 05:31:25PM +0200, Danilo Krummrich wrote:
> Rename "FB CMA" helpers to "FB DMA" helpers - considering the hierarchy
> of APIs (mm/cma -> dma -> fb dma) calling them "FB DMA" seems to be
> more applicable.
> 
> Besides that, commit e57924d4ae80 ("drm/doc: Task to rename CMA helpers")
> requests to rename the CMA helpers and implies that people seem to be
> confused about the naming.
> 
> In order to do this renaming the following script was used:
> 
> ```
> 	#!/bin/bash
> 
> 	DIRS="drivers/gpu include/drm Documentation/gpu"
> 
> 	REGEX_SYM_UPPER="[0-9A-Z_\-]"
> 	REGEX_SYM_LOWER="[0-9a-z_\-]"
> 
> 	REGEX_GREP_UPPER="(${REGEX_SYM_UPPER}*)(FB)_CMA_(${REGEX_SYM_UPPER}*)"
> 	REGEX_GREP_LOWER="(${REGEX_SYM_LOWER}*)(fb)_cma_(${REGEX_SYM_LOWER}*)"
> 
> 	REGEX_SED_UPPER="s/${REGEX_GREP_UPPER}/\1\2_DMA_\3/g"
> 	REGEX_SED_LOWER="s/${REGEX_GREP_LOWER}/\1\2_dma_\3/g"
> 
> 	# Find all upper case 'CMA' symbols and replace them with 'DMA'.
> 	for ff in $(grep -REHl "${REGEX_GREP_UPPER}" $DIRS)
> 	do
> 	       sed -i -E "$REGEX_SED_UPPER" $ff
> 	done
> 
> 	# Find all lower case 'cma' symbols and replace them with 'dma'.
> 	for ff in $(grep -REHl "${REGEX_GREP_LOWER}" $DIRS)
> 	do
> 	       sed -i -E "$REGEX_SED_LOWER" $ff
> 	done
> 
> 	# Replace all occurrences of 'CMA' / 'cma' in comments and
> 	# documentation files with 'DMA' / 'dma'.
> 	for ff in $(grep -RiHl " cma " $DIRS)
> 	do
> 		sed -i -E "s/ cma / dma /g" $ff
> 		sed -i -E "s/ CMA / DMA /g" $ff
> 	done
> ```
> 
> Only a few more manual modifications were needed, e.g. reverting the
> following modifications in some DRM Kconfig files
> 
>     -       select CMA if HAVE_DMA_CONTIGUOUS
>     +       select DMA if HAVE_DMA_CONTIGUOUS
> 
> as well as manually picking the occurrences of 'CMA'/'cma' in comments and
> documentation which relate to "FB CMA", but not "GEM CMA".
> 
> This patch is compile-time tested building a x86_64 kernel with
> `make allyesconfig && make drivers/gpu/drm`.
> 
> Acked-by: Thomas Zimmermann <tzimmermann@...e.de>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> Signed-off-by: Danilo Krummrich <dakr@...hat.com>

For the most part I like the patch.
But there is a few cases I would like to see fixed.


> diff --git a/drivers/gpu/drm/arm/hdlcd_drv.c b/drivers/gpu/drm/arm/hdlcd_drv.c
> index e89ae0ec60eb..fab18135f12b 100644
> --- a/drivers/gpu/drm/arm/hdlcd_drv.c
> +++ b/drivers/gpu/drm/arm/hdlcd_drv.c
> @@ -25,7 +25,7 @@
>  #include <drm/drm_crtc.h>
>  #include <drm/drm_debugfs.h>
>  #include <drm/drm_drv.h>
> -#include <drm/drm_fb_cma_helper.h>
> +#include <drm/drm_fb_dma_helper.h>
>  #include <drm/drm_fb_helper.h>
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>


The only change in the file above is the rename of the include file.
This is a strong hint that the include is not needed and the correct fix
is to drop the include. There are more cases like the above.

This is a manual process on top of what you could automate, but then I
suggest to identify them and remove the includes before you change the
file name.

Or if anyone applies the patches then at least do it in a follow-up at
the places will never be easier to spot.

So with this cleanup done either before or after this patch.
Acked-by: Sam Ravnborg <sam@...nborg.org>

	Sam