Re: [PATCH v4 3/4] drm: Add library for shmem backed GEM objects

[Daniel Vetter <daniel@ffwll.ch>]

On Wed, Oct 10, 2018 at 09:14:50PM +0200, Noralf Trønnes wrote:
> Den 01.10.2018 09.46, skrev Daniel Vetter:
> > On Wed, Sep 26, 2018 at 04:59:32PM +0200, Noralf Trønnes wrote:
> > > +int drm_gem_shmem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct *vma)
> > > +{
> > > +	struct drm_gem_shmem_object *shmem = to_drm_gem_shmem_obj(obj);
> > > +	int ret;
> > > +
> > > +	ret = drm_gem_mmap_obj(obj, obj->size, vma);
> > > +	if (ret)
> > > +		return ret;
> > > +
> > > +	return drm_gem_shmem_mmap_obj(shmem, vma);
> > > +}
> > If we'd use the gem vma offset manager and adjust offsets and then call
> > into the gem mmap stuff I think we could make this 100% generic. That
> > would also avoid the need to add the gem_ops->prime_mmap callback, since
> > we'll have a default that should work for everyone.
> 
> Is this what you had in mind?
> 
> int drm_gem_prime_mmap(struct drm_gem_object *obj, struct vm_area_struct
> *vma)
> {
>     /* Used by drm_gem_mmap() to lookup the GEM object */
>     struct drm_file priv = {
>         .minor = obj->dev->primary,
>     };
>     struct file fil = {
>         .private_data = &priv,
>     };
>     int ret;
> 
>     ret = drm_vma_node_allow(&obj->vma_node, &priv);
>     if (ret)
>         return ret;
> 
>     vma->vm_pgoff += drm_vma_node_start(&obj->vma_node);

Yup, this offset adjusting is what I had in mind.
-Daniel

>     ret = obj->dev->driver->fops->mmap(&fil, vma);
> 
>     drm_vma_node_revoke(&obj->vma_node, &priv);
> 
>     return ret;
> }
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel