[patch V4 39/68] locking/ww_mutex: Gather mutex_waiter initialization

From: Thomas Gleixner
Date: Wed Aug 11 2021 - 08:25:30 EST


From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>

---
kernel/locking/mutex-debug.c | 1 +
kernel/locking/mutex.c | 12 +++---------
2 files changed, 4 insertions(+), 9 deletions(-)
---
--- a/kernel/locking/mutex-debug.c
+++ b/kernel/locking/mutex-debug.c
@@ -30,6 +30,7 @@ void debug_mutex_lock_common(struct mute
memset(waiter, MUTEX_DEBUG_INIT, sizeof(*waiter));
waiter->magic = waiter;
INIT_LIST_HEAD(&waiter->list);
+ waiter->ww_ctx = MUTEX_POISON_WW_CTX;
}

void debug_mutex_wake_waiter(struct mutex *lock, struct mutex_waiter *waiter)
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -980,17 +980,15 @@ static __always_inline int __sched
}

debug_mutex_lock_common(lock, &waiter);
+ waiter.task = current;
+ if (ww_ctx)
+ waiter.ww_ctx = ww_ctx;

lock_contended(&lock->dep_map, ip);

if (!use_ww_ctx) {
/* add waiting tasks to the end of the waitqueue (FIFO): */
__mutex_add_waiter(lock, &waiter, &lock->wait_list);
-
-
-#ifdef CONFIG_DEBUG_MUTEXES
- waiter.ww_ctx = MUTEX_POISON_WW_CTX;
-#endif
} else {
/*
* Add in stamp order, waking up waiters that must kill
@@ -999,12 +997,8 @@ static __always_inline int __sched
ret = __ww_mutex_add_waiter(&waiter, lock, ww_ctx);
if (ret)
goto err_early_kill;
-
- waiter.ww_ctx = ww_ctx;
}

- waiter.task = current;
-
set_current_state(state);
for (;;) {
/*