From mboxrd@z Thu Jan  1 00:00:00 1970
From: Sascha Hauer <s.hauer@pengutronix.de>
Subject: Re: [PATCH v2] DRM: add drm gem cma helper
Date: Tue, 5 Jun 2012 09:56:21 +0200
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To: InKi Dae <daeinki@gmail.com>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>, dri-devel@lists.freedesktop.org
List-Id: dri-devel@lists.freedesktop.org

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,
> >> + =A0 =A0 =A0 =A0 =A0 =A0 unsigned int size)
> >> +{
> >> + =A0 =A0 struct drm_gem_cma_object *cma_obj;
> >> + =A0 =A0 struct drm_gem_object *gem_obj;
> >> + =A0 =A0 int ret;
> >> +
> >> + =A0 =A0 size =3D round_up(size, PAGE_SIZE);
> >> +
> >> + =A0 =A0 cma_obj =3D kzalloc(sizeof(*cma_obj), GFP_KERNEL);
> >> + =A0 =A0 if (!cma_obj)
> >> + =A0 =A0 =A0 =A0 =A0 =A0 return ERR_PTR(-ENOMEM);
> >> +
> >> + =A0 =A0 cma_obj->vaddr =3D dma_alloc_writecombine(drm->dev, size,
> >> + =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 &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.

> >> + =A0 =A0 struct drm_gem_object *gem_obj;
> >> + =A0 =A0 struct drm_gem_cma_object *cma_obj;
> >> + =A0 =A0 int ret;
> >> +
> >> + =A0 =A0 ret =3D drm_gem_mmap(filp, vma);
> >> + =A0 =A0 if (ret)
> >> + =A0 =A0 =A0 =A0 =A0 =A0 return ret;
> >> +
> >> + =A0 =A0 gem_obj =3D vma->vm_private_data;
> >> + =A0 =A0 cma_obj =3D 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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