[PATCH v2 10/38] drm/gem: fold drm_gem_object_put_unlocked and __drm_gem_object_put()

[Daniel Vetter]

On Fri, May 15, 2020 at 10:50:50AM +0100, Emil Velikov wrote:
> From: Emil Velikov <emil.velikov at collabora.com>
> 
> With earlier patch we removed the overhead so now we can lift the helper
> into the header effectively folding it with __drm_object_put.
> 
> v2: drop struct_mutex references (Daniel)
> 
> Signed-off-by: Emil Velikov <emil.velikov at collabora.com>
> Acked-by: Sam Ravnborg <sam at ravnborg.org> (v1)
> Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>
> ---
>  drivers/gpu/drm/drm_gem.c                  | 19 -------------------
>  drivers/gpu/drm/i915/gem/i915_gem_object.h |  2 +-
>  include/drm/drm_drv.h                      |  2 --
>  include/drm/drm_gem.h                      | 16 +++-------------
>  4 files changed, 4 insertions(+), 35 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index dab8763b2e73..599d5ff53b73 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -982,25 +982,6 @@ drm_gem_object_free(struct kref *kref)
>  }
>  EXPORT_SYMBOL(drm_gem_object_free);
>  
> -/**
> - * drm_gem_object_put_unlocked - drop a GEM buffer object reference
> - * @obj: GEM buffer object
> - *
> - * This releases a reference to @obj. Callers must not hold the
> - * &drm_device.struct_mutex lock when calling this function.
> - *
> - * See also __drm_gem_object_put().
> - */
> -void
> -drm_gem_object_put_unlocked(struct drm_gem_object *obj)
> -{
> -	if (!obj)
> -		return;
> -
> -	kref_put(&obj->refcount, drm_gem_object_free);
> -}
> -EXPORT_SYMBOL(drm_gem_object_put_unlocked);
> -
>  /**
>   * drm_gem_object_put - release a GEM buffer object reference
>   * @obj: GEM buffer object
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_object.h b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> index 2faa481cc18f..41351cbf31b5 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_object.h
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_object.h
> @@ -105,7 +105,7 @@ __attribute__((nonnull))
>  static inline void
>  i915_gem_object_put(struct drm_i915_gem_object *obj)
>  {
> -	__drm_gem_object_put(&obj->base);
> +	drm_gem_object_put_unlocked(&obj->base);
>  }
>  
>  #define assert_object_held(obj) dma_resv_assert_held((obj)->base.resv)
> diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
> index e6eff508f687..bb924cddc09c 100644
> --- a/include/drm/drm_drv.h
> +++ b/include/drm/drm_drv.h
> @@ -332,8 +332,6 @@ struct drm_driver {
>  	 *
>  	 * This is deprecated and should not be used by new drivers. Use
>  	 * &drm_gem_object_funcs.free instead.
> -	 * Compared to @gem_free_object this is not encumbered with
> -	 * &drm_device.struct_mutex legacy locking schemes.

Ah here's the two lines removed that I missed in the earlier patch. If you
feel like moving that hunk or not, r-b: me on both is ok.
-Daniel

>  	 */
>  	void (*gem_free_object_unlocked) (struct drm_gem_object *obj);
>  
> diff --git a/include/drm/drm_gem.h b/include/drm/drm_gem.h
> index ec2d24a60a76..c3bdade093ae 100644
> --- a/include/drm/drm_gem.h
> +++ b/include/drm/drm_gem.h
> @@ -364,27 +364,17 @@ static inline void drm_gem_object_get(struct drm_gem_object *obj)
>  }
>  
>  /**
> - * __drm_gem_object_put - raw function to release a GEM buffer object reference
> + * drm_gem_object_put_unlocked - drop a GEM buffer object reference
>   * @obj: GEM buffer object
>   *
> - * This function is meant to be used by drivers which are not encumbered with
> - * &drm_device.struct_mutex legacy locking and which are using the
> - * gem_free_object_unlocked callback. It avoids all the locking checks and
> - * locking overhead of drm_gem_object_put() and drm_gem_object_put_unlocked().
> - *
> - * Drivers should never call this directly in their code. Instead they should
> - * wrap it up into a ``driver_gem_object_put(struct driver_gem_object *obj)``
> - * wrapper function, and use that. Shared code should never call this, to
> - * avoid breaking drivers by accident which still depend upon
> - * &drm_device.struct_mutex locking.
> + * This releases a reference to @obj.
>   */
>  static inline void
> -__drm_gem_object_put(struct drm_gem_object *obj)
> +drm_gem_object_put_unlocked(struct drm_gem_object *obj)
>  {
>  	kref_put(&obj->refcount, drm_gem_object_free);
>  }
>  
> -void drm_gem_object_put_unlocked(struct drm_gem_object *obj);
>  void drm_gem_object_put(struct drm_gem_object *obj);
>  
>  int drm_gem_handle_create(struct drm_file *file_priv,
> -- 
> 2.25.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch