[tip: locking/core] lockdep: Use memset_startat() helper in reinit_class()

[tip-bot2 for Xiu Jianfeng]

The following commit has been merged into the locking/core branch of tip:

Commit-ID:     e204193b138af347fbbbe026e68cb3385112f387
Gitweb:        https://git.kernel.org/tip/e204193b138af347fbbbe026e68cb3385112f387
Author:        Xiu Jianfeng <xiujianfeng@xxxxxxxxxx>
AuthorDate:    Mon, 13 Dec 2021 21:26:18 +08:00
Committer:     Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Tue, 25 Jan 2022 22:30:27 +01:00

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@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Link: https://lkml.kernel.org/r/20211213132618.105737-1-xiujianfeng@xxxxxxxxxx
---
 kernel/locking/lockdep.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index 4a882f8..89b3df5 100644
--- 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));