static int ion_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
{
	struct ion_buffer *buffer = dmabuf->priv;
	int ret = 0;

	if (!buffer->heap->ops->map_user) {
		pr_err("%s: this heap does not define a method for mapping to userspace\n",
			__func__);
		return -EINVAL;
	}

	if (ion_buffer_fault_user_mappings(buffer)) {
		vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND |
							VM_DONTDUMP;
		vma->vm_private_data = buffer;
		vma->vm_ops = &ion_vma_ops;
		ion_vm_open(vma);
		return 0;
	}

	if (!(buffer->flags & ION_FLAG_CACHED))
		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

	mutex_lock(&buffer->lock);
	/* now map it to userspace */
	ret = buffer->heap->ops->map_user(buffer->heap, buffer, vma);
	mutex_unlock(&buffer->lock);

	if (ret)
		pr_err("%s: failure mapping buffer to userspace\n",
		       __func__);

	return ret;
}
static int ion_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)
{
	struct ion_buffer *buffer = dmabuf->priv;
	int ret = 0;

	if (!buffer->heap->ops->map_user) {
		pr_err("%s: this heap does not define a method for mapping to userspace\n",
			__func__);
		return -EINVAL;
	}

	if (ion_buffer_fault_user_mappings(buffer)) {
		vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND |
							VM_DONTDUMP;
		vma->vm_private_data = buffer;
		vma->vm_ops = &ion_vma_ops;
		ion_vm_open(vma);
		return 0;
	}

	if (!(buffer->flags & ION_FLAG_CACHED))
		vma->vm_page_prot = pgprot_writecombine(vma->vm_page_prot);

	mutex_lock(&buffer->lock);
	 
	ret = buffer->heap->ops->map_user(buffer->heap, buffer, vma);
	mutex_unlock(&buffer->lock);

	if (ret)
		pr_err("%s: failure mapping buffer to userspace\n",
		       __func__);

	return ret;
}