[PATCH 05/52] drm/mipi_dbi: Use drmm_add_final_kfree in all drivers

Thomas Zimmermann tzimmermann at suse.de
Wed Feb 19 11:47:24 UTC 2020


Hi Daniel,

good idea. I guess it's the simple encoder's fault. :) I only read
briefly over the whole thing.

Am 19.02.20 um 11:20 schrieb Daniel Vetter:
> They all share mipi_dbi_release so we need to switch them all
> together. With this we can drop the final kfree from the release
> function.
> 
> Aside, I think we could perhaps have a tiny additional helper for
> these mipi_dbi drivers, the first few lines around devm_drm_dev_init
> are all the same (except for the drm_driver pointer).
> 
> Cc: Maarten Lankhorst <maarten.lankhorst at linux.intel.com>
> Cc: Maxime Ripard <mripard at kernel.org>
> Cc: Thomas Zimmermann <tzimmermann at suse.de>
> Cc: David Airlie <airlied at linux.ie>
> Cc: Daniel Vetter <daniel at ffwll.ch>
> Cc: Eric Anholt <eric at anholt.net>
> Cc: David Lechner <david at lechnology.com>
> Cc: Kamlesh Gurudasani <kamlesh.gurudasani at gmail.com>
> Cc: "Noralf Trønnes" <noralf at tronnes.org>
> Cc: Sam Ravnborg <sam at ravnborg.org>
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
> ---
>  drivers/gpu/drm/drm_mipi_dbi.c  | 3 ---
>  drivers/gpu/drm/tiny/hx8357d.c  | 2 ++
>  drivers/gpu/drm/tiny/ili9225.c  | 2 ++
>  drivers/gpu/drm/tiny/ili9341.c  | 2 ++
>  drivers/gpu/drm/tiny/ili9486.c  | 2 ++
>  drivers/gpu/drm/tiny/mi0283qt.c | 2 ++
>  drivers/gpu/drm/tiny/st7586.c   | 2 ++
>  drivers/gpu/drm/tiny/st7735r.c  | 2 ++
>  8 files changed, 14 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
> index 558baf989f5a..069603dfcd10 100644
> --- a/drivers/gpu/drm/drm_mipi_dbi.c
> +++ b/drivers/gpu/drm/drm_mipi_dbi.c
> @@ -588,13 +588,10 @@ EXPORT_SYMBOL(mipi_dbi_dev_init);
>   */
>  void mipi_dbi_release(struct drm_device *drm)
>  {
> -	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(drm);
> -
>  	DRM_DEBUG_DRIVER("\n");
>  
>  	drm_mode_config_cleanup(drm);
>  	drm_dev_fini(drm);
> -	kfree(dbidev);
>  }
>  EXPORT_SYMBOL(mipi_dbi_release);
>  
> diff --git a/drivers/gpu/drm/tiny/hx8357d.c b/drivers/gpu/drm/tiny/hx8357d.c
> index 9af8ff84974f..42bc5dadcb1c 100644
> --- a/drivers/gpu/drm/tiny/hx8357d.c
> +++ b/drivers/gpu/drm/tiny/hx8357d.c
> @@ -21,6 +21,7 @@
>  #include <drm/drm_fb_helper.h>
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_managed.h>
>  #include <drm/drm_mipi_dbi.h>
>  #include <drm/drm_modeset_helper.h>
>  #include <video/mipi_display.h>
> @@ -236,6 +237,7 @@ static int hx8357d_probe(struct spi_device *spi)
>  		kfree(dbidev);
>  		return ret;
>  	}
> +	drmm_add_final_kfree(drm, dbidev);

I'd prefer something else than drmm_add_final_kfree().

From what I understand, drmmadd_add_final_kfree() is required so that
the device instance itself gets free. But wiring up garbage collection
manually is easy to forget and a somewhat odd design. If we have to do
that, there's little benefit over calling kfree in the release callback.

Instead, could drivers rather be converted to drm_dev_alloc() where
possible?

For the other cases, could there be a dedicated allocator function that
invokes drmm_add_final_kfree()? Like that

  void*
  __drmm_kzalloc_dev(size_t size, size_t dev_off)
  {
      void *parent = kzalloc(size)

      drm_device *dev = (parent + dev_off)

      __drmm_add_final_kfree(dev, parent);

      return parent;
  }

  /*
   * takes the name of driver's device structure and the
   * name of the drm device structure embedded within
   */
  drmm_kzalloc(parent_type, base)
    (parent_type*)__drm_kzalloc_dev(sizeof(parent_type),
			offsetof(parent_type, base));

Best regards
Thomas

>  
>  	drm_mode_config_init(drm);
>  
> diff --git a/drivers/gpu/drm/tiny/ili9225.c b/drivers/gpu/drm/tiny/ili9225.c
> index 802fb8dde1b6..aae88dc5b3f7 100644
> --- a/drivers/gpu/drm/tiny/ili9225.c
> +++ b/drivers/gpu/drm/tiny/ili9225.c
> @@ -24,6 +24,7 @@
>  #include <drm/drm_fourcc.h>
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_managed.h>
>  #include <drm/drm_mipi_dbi.h>
>  #include <drm/drm_rect.h>
>  
> @@ -387,6 +388,7 @@ static int ili9225_probe(struct spi_device *spi)
>  		kfree(dbidev);
>  		return ret;
>  	}
> +	drmm_add_final_kfree(drm, dbidev);
>  
>  	drm_mode_config_init(drm);
>  
> diff --git a/drivers/gpu/drm/tiny/ili9341.c b/drivers/gpu/drm/tiny/ili9341.c
> index 33b51dc7faa8..7d40cb4ff72b 100644
> --- a/drivers/gpu/drm/tiny/ili9341.c
> +++ b/drivers/gpu/drm/tiny/ili9341.c
> @@ -20,6 +20,7 @@
>  #include <drm/drm_fb_helper.h>
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_managed.h>
>  #include <drm/drm_mipi_dbi.h>
>  #include <drm/drm_modeset_helper.h>
>  #include <video/mipi_display.h>
> @@ -194,6 +195,7 @@ static int ili9341_probe(struct spi_device *spi)
>  		kfree(dbidev);
>  		return ret;
>  	}
> +	drmm_add_final_kfree(drm, dbidev);
>  
>  	drm_mode_config_init(drm);
>  
> diff --git a/drivers/gpu/drm/tiny/ili9486.c b/drivers/gpu/drm/tiny/ili9486.c
> index 5084b38c1a71..7d735fc67498 100644
> --- a/drivers/gpu/drm/tiny/ili9486.c
> +++ b/drivers/gpu/drm/tiny/ili9486.c
> @@ -19,6 +19,7 @@
>  #include <drm/drm_fb_helper.h>
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_managed.h>
>  #include <drm/drm_mipi_dbi.h>
>  #include <drm/drm_modeset_helper.h>
>  
> @@ -208,6 +209,7 @@ static int ili9486_probe(struct spi_device *spi)
>  		kfree(dbidev);
>  		return ret;
>  	}
> +	drmm_add_final_kfree(drm, dbidev);
>  
>  	drm_mode_config_init(drm);
>  
> diff --git a/drivers/gpu/drm/tiny/mi0283qt.c b/drivers/gpu/drm/tiny/mi0283qt.c
> index e2cfd9a17143..8555a56bce8c 100644
> --- a/drivers/gpu/drm/tiny/mi0283qt.c
> +++ b/drivers/gpu/drm/tiny/mi0283qt.c
> @@ -18,6 +18,7 @@
>  #include <drm/drm_fb_helper.h>
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_managed.h>
>  #include <drm/drm_mipi_dbi.h>
>  #include <drm/drm_modeset_helper.h>
>  #include <video/mipi_display.h>
> @@ -198,6 +199,7 @@ static int mi0283qt_probe(struct spi_device *spi)
>  		kfree(dbidev);
>  		return ret;
>  	}
> +	drmm_add_final_kfree(drm, dbidev);
>  
>  	drm_mode_config_init(drm);
>  
> diff --git a/drivers/gpu/drm/tiny/st7586.c b/drivers/gpu/drm/tiny/st7586.c
> index 9ef559dd3191..427c2561f5f4 100644
> --- a/drivers/gpu/drm/tiny/st7586.c
> +++ b/drivers/gpu/drm/tiny/st7586.c
> @@ -21,6 +21,7 @@
>  #include <drm/drm_format_helper.h>
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_managed.h>
>  #include <drm/drm_mipi_dbi.h>
>  #include <drm/drm_rect.h>
>  
> @@ -328,6 +329,7 @@ static int st7586_probe(struct spi_device *spi)
>  		kfree(dbidev);
>  		return ret;
>  	}
> +	drmm_add_final_kfree(drm, dbidev);
>  
>  	drm_mode_config_init(drm);
>  
> diff --git a/drivers/gpu/drm/tiny/st7735r.c b/drivers/gpu/drm/tiny/st7735r.c
> index 18b925df6e51..b447235c3d47 100644
> --- a/drivers/gpu/drm/tiny/st7735r.c
> +++ b/drivers/gpu/drm/tiny/st7735r.c
> @@ -21,6 +21,7 @@
>  #include <drm/drm_fb_helper.h>
>  #include <drm/drm_gem_cma_helper.h>
>  #include <drm/drm_gem_framebuffer_helper.h>
> +#include <drm/drm_managed.h>
>  #include <drm/drm_mipi_dbi.h>
>  
>  #define ST7735R_FRMCTR1		0xb1
> @@ -209,6 +210,7 @@ static int st7735r_probe(struct spi_device *spi)
>  		kfree(dbidev);
>  		return ret;
>  	}
> +	drmm_add_final_kfree(drm, dbidev);
>  
>  	drm_mode_config_init(drm);
>  
> 

-- 
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Maxfeldstr. 5, 90409 Nürnberg, Germany
(HRB 36809, AG Nürnberg)
Geschäftsführer: Felix Imendörffer

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