[PATCH v2] DRM: add drm gem cma helper

[Sascha Hauer]

On Fri, Jun 01, 2012 at 12:29:47AM +0900, InKi Dae wrote:
> Hi Sascha,
> 
> >> +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);
> 
> how about calling drm_gem_cma_buf_allocate() instead of
> dma_alloc_wirtecombine() for consistency in using dma api so its call
> flow would be "dma_gem_cma_buf_allocate() ->
> dma_alloc_writecombine()".

What do you mean? There is no drm_gem_cma_buf_allocate() function.

> >> +     struct drm_gem_object *gem_obj;
> >> +     struct drm_gem_cma_object *cma_obj;
> >> +     int ret;
> >> +
> >> +     ret = drm_gem_mmap(filp, vma);
> >> +     if (ret)
> >> +             return ret;
> >> +
> >> +     gem_obj = vma->vm_private_data;
> >> +     cma_obj = to_drm_gem_cma_obj(gem_obj);
> 
> it's likely to need checking if user space size is valid or not here.
> like this;
> if (vma->end - vma->start > gem_obj->size) {
>           error message;
>          and some exceptions;
> }

This is already done in drm_gem_mmap().

Sascha

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