[tip: locking/core] locking/ww_mutex: Gather mutex_waiter initialization

[tip-bot2 for Peter Zijlstra]

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

Commit-ID:     c0afb0ffc06e6b4e492a3b711f1fb32074f9949c
Gitweb:        https://git.kernel.org/tip/c0afb0ffc06e6b4e492a3b711f1fb32074f9949c
Author:        Peter Zijlstra <peterz@xxxxxxxxxxxxx>
AuthorDate:    Sun, 15 Aug 2021 23:28:39 +02:00
Committer:     Ingo Molnar <mingo@xxxxxxxxxx>
CommitterDate: Tue, 17 Aug 2021 19:04:41 +02:00

locking/ww_mutex: Gather mutex_waiter initialization

Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Link: https://lore.kernel.org/r/20210815211304.281927514@xxxxxxxxxxxxx
---
 kernel/locking/mutex-debug.c |  1 +
 kernel/locking/mutex.c       | 12 +++---------
 2 files changed, 4 insertions(+), 9 deletions(-)

diff --git a/kernel/locking/mutex-debug.c b/kernel/locking/mutex-debug.c
index 7ef5a36..bc8abb8 100644
--- a/kernel/locking/mutex-debug.c
+++ b/kernel/locking/mutex-debug.c
@@ -30,6 +30,7 @@ void debug_mutex_lock_common(struct mutex *lock, struct mutex_waiter *waiter)
 	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)
diff --git a/kernel/locking/mutex.c b/kernel/locking/mutex.c
index 73ad862..6cb27c5 100644
--- a/kernel/locking/mutex.c
+++ b/kernel/locking/mutex.c
@@ -982,17 +982,15 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 	}
 
 	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
@@ -1001,12 +999,8 @@ __mutex_lock_common(struct mutex *lock, unsigned int state, unsigned int subclas
 		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 (;;) {
 		bool first;