Convert intel uncore to struct_size

Need to do a bit of rearranging to make this work.
Signed-off-by: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Kees Cook <keescook@chromium.org>

arch/x86/events/intel/uncore.c

@@ -865,8 +865,6 @@ static void uncore_types_exit(struct intel_uncore_type **types)
 static int __init uncore_type_init(struct intel_uncore_type *type, bool setid)
 {
 	struct intel_uncore_pmu *pmus;
-	struct attribute_group *attr_group;
-	struct attribute **attrs;
 	size_t size;
 	int i, j;
 
@@ -891,21 +889,24 @@ static int __init uncore_type_init(struct intel_uncore_type *type, bool setid)
 				0, type->num_counters, 0, 0);
 
 	if (type->event_descs) {
+		struct {
+			struct attribute_group group;
+			struct attribute *attrs[];
+		} *attr_group;
 		for (i = 0; type->event_descs[i].attr.attr.name; i++);
 
-		attr_group = kzalloc(sizeof(struct attribute *) * (i + 1) +
-					sizeof(*attr_group), GFP_KERNEL);
+		attr_group = kzalloc(struct_size(attr_group, attrs, i + 1),
+								GFP_KERNEL);
 		if (!attr_group)
 			goto err;
 
-		attrs = (struct attribute **)(attr_group + 1);
-		attr_group->name = "events";
-		attr_group->attrs = attrs;
+		attr_group->group.name = "events";
+		attr_group->group.attrs = attr_group->attrs;
 
 		for (j = 0; j < i; j++)
-			attrs[j] = &type->event_descs[j].attr.attr;
+			attr_group->attrs[j] = &type->event_descs[j].attr.attr;
 
-		type->events_group = attr_group;
+		type->events_group = &attr_group->group;
 	}
 
 	type->pmu_group = &uncore_pmu_attr_group;