[PATCH v3 32/37] drm/i915: Add cpu and lmem fault handlers

[Chris Wilson]

Quoting Matthew Auld (2019-08-09 23:26:38)
> -void __i915_gem_object_release_mmap(struct drm_i915_gem_object *obj)
> +static vm_fault_t i915_gem_fault_cpu(struct vm_fault *vmf)
> +{
> +       struct vm_area_struct *area = vmf->vma;
> +       struct i915_mmap_offset *priv = area->vm_private_data;
> +       struct drm_i915_gem_object *obj = priv->obj;
> +       struct drm_device *dev = obj->base.dev;
> +       struct drm_i915_private *dev_priv = to_i915(dev);
> +       vm_fault_t vmf_ret;
> +       unsigned long size = area->vm_end - area->vm_start;
> +       bool write = area->vm_flags & VM_WRITE;
> +       int i, ret;
> +
> +       /* Sanity check that we allow writing into this object */
> +       if (i915_gem_object_is_readonly(obj) && write)
> +               return VM_FAULT_SIGBUS;
> +
> +       ret = i915_gem_object_pin_pages(obj);
if (err)
	return i915_error_to_vmf_fault(err);

> +               goto err;
> +
> +       for (i = 0; i < size >> PAGE_SHIFT; i++) {
> +               struct page *page = i915_gem_object_get_page(obj, i);
> +               vmf_ret = vmf_insert_pfn(area,
> +                                        (unsigned long)area->vm_start + i * PAGE_SIZE,
> +                                        page_to_pfn(page));
> +               if (vmf_ret & VM_FAULT_ERROR) {
> +                       ret = vm_fault_to_errno(vmf_ret, 0);
> +                       break;
> +               }
> +       }
> +
> +       i915_gem_object_unpin_pages(obj);

return vmf_ret;