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Date:   Sun, 8 Aug 2021 13:41:16 -0700
From:   Davidlohr Bueso <dave@stgolabs.net>
To:     Thomas Gleixner <tglx@linutronix.de>
Cc:     LKML <linux-kernel@vger.kernel.org>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@kernel.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Steven Rostedt <rostedt@goodmis.org>,
        Daniel Bristot de Oliveira <bristot@redhat.com>,
        Will Deacon <will@kernel.org>,
        Waiman Long <longman@redhat.com>,
        Boqun Feng <boqun.feng@gmail.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        Mike Galbraith <efault@gmx.de>
Subject: Re: [patch V3 15/64] rtmutex: Provide rt_mutex_base_is_locked()
Message-ID: <20210808204116.rckeqq7hu4ofbitg@offworld>
References: <20210805151300.330412127@linutronix.de>
 <20210805153953.683678014@linutronix.de>
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>+/**
>+ * rt_mutex_base_is_locked - is the rtmutex locked
>+ * @lock: the mutex to be queried
>+ *
>+ * Returns true if the mutex is locked, false if unlocked.
>+ */
>+static inline bool rt_mutex_base_is_locked(struct rt_mutex_base *lock)
>+{
>+	return lock->owner != NULL;

Does this want to be READ_ONCE()? While not a big deal because
it's ultimately only used by drm debugging, I don't see any harm
in avoiding potential tearing.

Thanks,
Davidlohr