drm/i915/selftests: Make evict tolerant of foreign objects

The evict selftests presumed that all objects in use had been allocated
by itself. This is a dubious claim and so instead of asserting complete
control over the object lists, take (temporary) ownership of them
instead.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190118113632.7056-1-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/selftests/i915_gem_evict.c

@@ -31,30 +31,63 @@
 
 static int populate_ggtt(struct drm_i915_private *i915)
 {
-	struct drm_i915_gem_object *obj;
+	struct drm_i915_gem_object *obj, *on;
+	unsigned long expected_unbound, expected_bound;
+	unsigned long unbound, bound, count;
 	u64 size;
+	int err;
+
+	expected_unbound = 0;
+	list_for_each_entry(obj, &i915->mm.unbound_list, mm.link) {
+		i915_gem_object_get(obj);
+		expected_unbound++;
+	}
 
+	expected_bound = 0;
+	list_for_each_entry(obj, &i915->mm.bound_list, mm.link) {
+		i915_gem_object_get(obj);
+		expected_bound++;
+	}
+
+	count = 0;
 	for (size = 0;
 	     size + I915_GTT_PAGE_SIZE <= i915->ggtt.vm.total;
 	     size += I915_GTT_PAGE_SIZE) {
 		struct i915_vma *vma;
 
 		obj = i915_gem_object_create_internal(i915, I915_GTT_PAGE_SIZE);
-		if (IS_ERR(obj))
-			return PTR_ERR(obj);
+		if (IS_ERR(obj)) {
+			err = PTR_ERR(obj);
+			goto cleanup;
+		}
 
 		vma = i915_gem_object_ggtt_pin(obj, NULL, 0, 0, 0);
-		if (IS_ERR(vma))
-			return PTR_ERR(vma);
+		if (IS_ERR(vma)) {
+			err = PTR_ERR(vma);
+			goto cleanup;
 		}
 
-	if (!list_empty(&i915->mm.unbound_list)) {
-		size = 0;
+		count++;
+	}
+
+	unbound = 0;
 	list_for_each_entry(obj, &i915->mm.unbound_list, mm.link)
-			size++;
+		unbound++;
+	if (unbound != expected_unbound) {
+		pr_err("%s: Found %lu objects unbound, expected %lu!\n",
+		       __func__, unbound, expected_unbound);
+		err = -EINVAL;
+		goto cleanup;
+	}
 
-		pr_err("Found %lld objects unbound!\n", size);
-		return -EINVAL;
+	bound = 0;
+	list_for_each_entry(obj, &i915->mm.bound_list, mm.link)
+		bound++;
+	if (bound != expected_bound + count) {
+		pr_err("%s: Found %lu objects bound, expected %lu!\n",
+		       __func__, bound, expected_bound + count);
+		err = -EINVAL;
+		goto cleanup;
 	}
 
 	if (list_empty(&i915->ggtt.vm.inactive_list)) {
@@ -63,6 +96,15 @@ static int populate_ggtt(struct drm_i915_private *i915)
 	}
 
 	return 0;
+
+cleanup:
+	list_for_each_entry_safe(obj, on, &i915->mm.unbound_list, mm.link)
+		i915_gem_object_put(obj);
+
+	list_for_each_entry_safe(obj, on, &i915->mm.bound_list, mm.link)
+		i915_gem_object_put(obj);
+
+	return err;
 }
 
 static void unpin_ggtt(struct drm_i915_private *i915)