Commit ec84b27f authored May 25, 2018 by Anna-Maria Gleixner Committed by Thomas Gleixner Jun 10, 2018

rcu: Update documentation of rcu_read_unlock()



Since commit b4abf910 ("rtmutex: Make wait_lock irq safe") the
explanation in rcu_read_unlock() documentation about irq unsafe rtmutex
wait_lock is no longer valid.

Remove it to prevent kernel developers reading the documentation to rely on
it.

Suggested-by: Eric W. Biederman <ebiederm@xmission.com>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: bigeasy@linutronix.de
Link: https://lkml.kernel.org/r/20180525090507.22248-2-anna-maria@linutronix.de

parent cd77849a

include/linux/rcupdate.h

+1 −3

Original line number	Diff line number	Diff line
		@@ -652,9 +652,7 @@ static inline void rcu_read_lock(void)
		* Unfortunately, this function acquires the scheduler's runqueue and
		* priority-inheritance spinlocks. This means that deadlock could result
		* if the caller of rcu_read_unlock() already holds one of these locks or
		* any lock that is ever acquired while holding them; or any lock which
		* can be taken from interrupt context because rcu_boost()->rt_mutex_lock()
		* does not disable irqs while taking ->wait_lock.
		* any lock that is ever acquired while holding them.
		*
		* That said, RCU readers are never priority boosted unless they were
		* preempted. Therefore, one way to avoid deadlock is to make sure

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