lockdep: Use memset_startat() helper in reinit_class()

use memset_startat() helper to simplify the code, there is no functional
change in this patch.

Signed-off-by: Xiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211213132618.105737-1-xiujianfeng@huawei.com

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 4a882f8..89b3df5 100644 (file)
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -6011,13 +6011,10 @@ static void zap_class(struct pending_free *pf, struct lock_class *class)
 
 static void reinit_class(struct lock_class *class)
 {
-       void *const p = class;
-       const unsigned int offset = offsetof(struct lock_class, key);
-
        WARN_ON_ONCE(!class->lock_entry.next);
        WARN_ON_ONCE(!list_empty(&class->locks_after));
        WARN_ON_ONCE(!list_empty(&class->locks_before));
-       memset(p + offset, 0, sizeof(*class) - offset);
+       memset_startat(class, 0, key);
        WARN_ON_ONCE(!class->lock_entry.next);
        WARN_ON_ONCE(!list_empty(&class->locks_after));
        WARN_ON_ONCE(!list_empty(&class->locks_before));