From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>, Will Deacon <will@kernel.org>,
Waiman Long <longman@redhat.com>,
Boqun Feng <boqun.feng@gmail.com>,
Thomas Gleixner <tglx@linutronix.de>,
Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Subject: [PATCH 1/2] rtmutex: Check explicit for TASK_RTLOCK_WAIT.
Date: Tue, 28 Sep 2021 17:00:05 +0200 [thread overview]
Message-ID: <20210928150006.597310-2-bigeasy@linutronix.de> (raw)
In-Reply-To: <20210928150006.597310-1-bigeasy@linutronix.de>
rt_mutex_wake_q_add() needs to need to distiguish between sleeping
locks (TASK_RTLOCK_WAIT) and normal locks which use TASK_NORMAL to use
the proper wake mechanism.
Instead of checking for != TASK_NORMAL make it more robust and check
explicit for TASK_RTLOCK_WAIT which is the reason why a different wake
mechanism is used.
No functional change.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/locking/rtmutex.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index 6bb116c559b4a..cafc259ec59d3 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -449,7 +449,7 @@ static __always_inline void rt_mutex_adjust_prio(struct task_struct *p)
static __always_inline void rt_mutex_wake_q_add(struct rt_wake_q_head *wqh,
struct rt_mutex_waiter *w)
{
- if (IS_ENABLED(CONFIG_PREEMPT_RT) && w->wake_state != TASK_NORMAL) {
+ if (IS_ENABLED(CONFIG_PREEMPT_RT) && w->wake_state == TASK_RTLOCK_WAIT) {
if (IS_ENABLED(CONFIG_PROVE_LOCKING))
WARN_ON_ONCE(wqh->rtlock_task);
get_task_struct(w->task);
--
2.33.0
next prev parent reply other threads:[~2021-09-28 15:00 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-28 15:00 [PATCH 0/2] rtmutex: Lockless reader wake + explicit check for TASK_RTLOCK_WAIT Sebastian Andrzej Siewior
2021-09-28 15:00 ` Sebastian Andrzej Siewior [this message]
2021-10-01 15:05 ` [tip: locking/core] rtmutex: Check explicit " tip-bot2 for Sebastian Andrzej Siewior
2021-09-28 15:00 ` [PATCH 2/2] rtmutex: Wake up the waiters lockless while dropping the read lock Sebastian Andrzej Siewior
2021-10-01 15:05 ` [tip: locking/core] " tip-bot2 for Thomas Gleixner
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