drm/i915/selftests: Avoid drm_gem_handle_create under struct_mutex

Despite us reloading the module around every selftest, the lockclasses
persist and the chains used in selftesting may then dictate how we are
allowed to nest locks during runtime testing. As such we have to be just
as careful, and in particular it turns out we are not allowed to nest
dev->object_name_lock (drm_gem_handle_create) inside dev->struct_mutex.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103830
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171121110652.1107-1-chris@chris-wilson.co.uk
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>

drivers/gpu/drm/i915/selftests/i915_gem_context.c

@@ -264,6 +264,23 @@ out_unmap:
 	return err;
 }
 
+static int file_add_object(struct drm_file *file,
+			    struct drm_i915_gem_object *obj)
+{
+	int err;
+
+	GEM_BUG_ON(obj->base.handle_count);
+
+	/* tie the object to the drm_file for easy reaping */
+	err = idr_alloc(&file->object_idr, &obj->base, 1, 0, GFP_KERNEL);
+	if (err < 0)
+		return  err;
+
+	i915_gem_object_get(obj);
+	obj->base.handle_count++;
+	return 0;
+}
+
 static struct drm_i915_gem_object *
 create_test_object(struct i915_gem_context *ctx,
 		   struct drm_file *file,
@@ -273,7 +290,6 @@ create_test_object(struct i915_gem_context *ctx,
 	struct i915_address_space *vm =
 		ctx->ppgtt ? &ctx->ppgtt->base : &ctx->i915->ggtt.base;
 	u64 size;
-	u32 handle;
 	int err;
 
 	size = min(vm->total / 2, 1024ull * DW_PER_PAGE * PAGE_SIZE);
@@ -283,8 +299,7 @@ create_test_object(struct i915_gem_context *ctx,
 	if (IS_ERR(obj))
 		return obj;
 
-	/* tie the handle to the drm_file for easy reaping */
-	err = drm_gem_handle_create(file, &obj->base, &handle);
+	err = file_add_object(file, obj);
 	i915_gem_object_put(obj);
 	if (err)
 		return ERR_PTR(err);