[PATCH v2 3/5] drm: GEM CMA: Split object creation into object alloc and DMA memory alloc

[Rob Clark]

On Mon, Jun 3, 2013 at 10:20 PM, Laurent Pinchart
<laurent.pinchart+renesas at ideasonboard.com> wrote:
> This allows creating a GEM CMA object without an associated DMA memory
> buffer, and will be used to implement DRM PRIME support.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>

Reviewed-by: Rob Clark <robdclark at gmail.com>

> ---
>  drivers/gpu/drm/drm_gem_cma_helper.c | 83 +++++++++++++++++++++---------------
>  1 file changed, 48 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
> index 0a7e011..8cce330 100644
> --- a/drivers/gpu/drm/drm_gem_cma_helper.c
> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c
> @@ -32,62 +32,73 @@ static unsigned int get_gem_mmap_offset(struct drm_gem_object *obj)
>         return (unsigned int)obj->map_list.hash.key << PAGE_SHIFT;
>  }
>
> -static void drm_gem_cma_buf_destroy(struct drm_device *drm,
> -               struct drm_gem_cma_object *cma_obj)
> -{
> -       dma_free_writecombine(drm->dev, cma_obj->base.size, cma_obj->vaddr,
> -                       cma_obj->paddr);
> -}
> -
>  /*
> - * drm_gem_cma_create - allocate an object with the given size
> + * __drm_gem_cma_create - Create a GEM CMA object without allocating memory
> + * @drm: The drm device
> + * @size: The GEM object size
>   *
> - * returns a struct drm_gem_cma_object* on success or ERR_PTR values
> - * on failure.
> + * This function creates and initializes a GEM CMA object of the given size, but
> + * doesn't allocate any memory to back the object.
> + *
> + * Return a struct drm_gem_cma_object* on success or ERR_PTR values on failure.
>   */
> -struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
> -               unsigned int size)
> +static struct drm_gem_cma_object *
> +__drm_gem_cma_create(struct drm_device *drm, unsigned int size)
>  {
>         struct drm_gem_cma_object *cma_obj;
>         struct drm_gem_object *gem_obj;
>         int ret;
>
> -       size = round_up(size, PAGE_SIZE);
> -
>         cma_obj = kzalloc(sizeof(*cma_obj), GFP_KERNEL);
>         if (!cma_obj)
>                 return ERR_PTR(-ENOMEM);
>
> -       cma_obj->vaddr = dma_alloc_writecombine(drm->dev, size,
> -                       &cma_obj->paddr, GFP_KERNEL | __GFP_NOWARN);
> -       if (!cma_obj->vaddr) {
> -               dev_err(drm->dev, "failed to allocate buffer with size %d\n", size);
> -               ret = -ENOMEM;
> -               goto err_dma_alloc;
> -       }
> -
>         gem_obj = &cma_obj->base;
>
>         ret = drm_gem_object_init(drm, gem_obj, size);
>         if (ret)
> -               goto err_obj_init;
> +               goto error;
>
>         ret = drm_gem_create_mmap_offset(gem_obj);
> -       if (ret)
> -               goto err_create_mmap_offset;
> +       if (ret) {
> +               drm_gem_object_release(gem_obj);
> +               goto error;
> +       }
>
>         return cma_obj;
>
> -err_create_mmap_offset:
> -       drm_gem_object_release(gem_obj);
> +error:
> +       kfree(cma_obj);
> +       return ERR_PTR(ret);
> +}
>
> -err_obj_init:
> -       drm_gem_cma_buf_destroy(drm, cma_obj);
> +/*
> + * drm_gem_cma_create - allocate an object with the given size
> + *
> + * returns a struct drm_gem_cma_object* on success or ERR_PTR values
> + * on failure.
> + */
> +struct drm_gem_cma_object *drm_gem_cma_create(struct drm_device *drm,
> +               unsigned int size)
> +{
> +       struct drm_gem_cma_object *cma_obj;
>
> -err_dma_alloc:
> -       kfree(cma_obj);
> +       size = round_up(size, PAGE_SIZE);
>
> -       return ERR_PTR(ret);
> +       cma_obj = __drm_gem_cma_create(drm, size);
> +       if (IS_ERR(cma_obj))
> +               return cma_obj;
> +
> +       cma_obj->vaddr = dma_alloc_writecombine(drm->dev, size,
> +                       &cma_obj->paddr, GFP_KERNEL | __GFP_NOWARN);
> +       if (!cma_obj->vaddr) {
> +               dev_err(drm->dev, "failed to allocate buffer with size %d\n",
> +                       size);
> +               drm_gem_cma_free_object(&cma_obj->base);
> +               return ERR_PTR(-ENOMEM);
> +       }
> +
> +       return cma_obj;
>  }
>  EXPORT_SYMBOL_GPL(drm_gem_cma_create);
>
> @@ -143,11 +154,13 @@ void drm_gem_cma_free_object(struct drm_gem_object *gem_obj)
>         if (gem_obj->map_list.map)
>                 drm_gem_free_mmap_offset(gem_obj);
>
> -       drm_gem_object_release(gem_obj);
> -
>         cma_obj = to_drm_gem_cma_obj(gem_obj);
>
> -       drm_gem_cma_buf_destroy(gem_obj->dev, cma_obj);
> +       if (cma_obj->vaddr)
> +               dma_free_writecombine(gem_obj->dev->dev, cma_obj->base.size,
> +                                     cma_obj->vaddr, cma_obj->paddr);
> +
> +       drm_gem_object_release(gem_obj);
>
>         kfree(cma_obj);
>  }
> --
> 1.8.1.5
>