Re: [PATCH 15/21] drm/rcar-du: Use GEM CMA object functions

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Thomas Zimmermann <tzimmermann@suse.de>
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Subject: Re: [PATCH 15/21] drm/rcar-du: Use GEM CMA object functions
Date: Fri, 22 May 2020 23:12:40 +0300	[thread overview]
Message-ID: <20200522201240.GE5824@pendragon.ideasonboard.com> (raw)
In-Reply-To: <20200522135246.10134-16-tzimmermann@suse.de>

Hi Thomas,

Thank you for the patch.

On Fri, May 22, 2020 at 03:52:40PM +0200, Thomas Zimmermann wrote:
> The rcar-du driver uses the default implementation for CMA functions;
> except for the .dumb_create callback. The __DRM_GEM_CMA_DRIVER_OPS macro
> now sets these defaults and .dumb_create in struct drm_driver. All
> remaining operations are provided by CMA GEM object functions.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
> ---
>  drivers/gpu/drm/rcar-du/rcar_du_drv.c | 11 +----------
>  1 file changed, 1 insertion(+), 10 deletions(-)
> 
> diff --git a/drivers/gpu/drm/rcar-du/rcar_du_drv.c b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> index 3e67cf70f0402..3728038cec1d1 100644
> --- a/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_du_drv.c
> @@ -476,16 +476,7 @@ DEFINE_DRM_GEM_CMA_FOPS(rcar_du_fops);
>  
>  static struct drm_driver rcar_du_driver = {
>  	.driver_features	= DRIVER_GEM | DRIVER_MODESET | DRIVER_ATOMIC,
> -	.gem_free_object_unlocked = drm_gem_cma_free_object,
> -	.gem_vm_ops		= &drm_gem_cma_vm_ops,
> -	.prime_handle_to_fd	= drm_gem_prime_handle_to_fd,
> -	.prime_fd_to_handle	= drm_gem_prime_fd_to_handle,
> -	.gem_prime_get_sg_table	= drm_gem_cma_prime_get_sg_table,
> -	.gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table,
> -	.gem_prime_vmap		= drm_gem_cma_prime_vmap,
> -	.gem_prime_vunmap	= drm_gem_cma_prime_vunmap,
> -	.gem_prime_mmap		= drm_gem_cma_prime_mmap,
> -	.dumb_create		= rcar_du_dumb_create,
> +	__DRM_GEM_CMA_DRIVER_OPS(rcar_du_dumb_create),

Your __DRM_GEM_CMA_DRIVER_OPS is defined as

#define __DRM_GEM_CMA_DRIVER_OPS(__dumb_create) \
        .gem_create_object      = drm_cma_gem_create_object_default_funcs, \
        .dumb_create            = (__dumb_create), \
        .prime_handle_to_fd     = drm_gem_prime_handle_to_fd, \
        .prime_fd_to_handle     = drm_gem_prime_fd_to_handle, \
        .gem_prime_import_sg_table = drm_gem_cma_prime_import_sg_table_vmap, \
        .gem_prime_mmap         = drm_gem_prime_mmap

The patch thus introduces several changes:

- drm_gem_cma_prime_import_sg_table_vmap() is used instead of
  drm_gem_cma_prime_import_sg_table() combined with .gem_prime_vmap()
  and .gem_prime_vunmap(). I believe that's fine, but splitting that
  change in a separate commit, or at the very least explaining it in
  details in the commit message, would make review easier.

- .gem_create_object() is now set. That seems to be OK, but I'm not sure
  to grasp all the implications. This should also be explained in the
  commit message, and ideally split to a separate patch.

- drm_gem_cma_prime_mmap() is replaced with drm_gem_prime_mmap(). Same
  comments :-)

This patch hides way too many changes in what is documented as just
innocent refactoring. It seems other drivers are affected too.

>  	.fops			= &rcar_du_fops,
>  	.name			= "rcar-du",
>  	.desc			= "Renesas R-Car Display Unit",

-- 
Regards,

Laurent Pinchart

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