Commit ec84b27f authored by Anna-Maria Gleixner's avatar Anna-Maria Gleixner Committed by Thomas Gleixner

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wait_lock is no longer valid.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: default avatarEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: default avatarAnna-Maria Gleixner <anna-maria@linutronix.de>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Reviewed-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: default avatar"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
...@@ -652,9 +652,7 @@ static inline void rcu_read_lock(void) ...@@ -652,9 +652,7 @@ static inline void rcu_read_lock(void)
* Unfortunately, this function acquires the scheduler's runqueue and * Unfortunately, this function acquires the scheduler's runqueue and
* priority-inheritance spinlocks. This means that deadlock could result * priority-inheritance spinlocks. This means that deadlock could result
* if the caller of rcu_read_unlock() already holds one of these locks or * 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 * any lock that is ever acquired while holding them.
* can be taken from interrupt context because rcu_boost()->rt_mutex_lock()
* does not disable irqs while taking ->wait_lock.
* *
* That said, RCU readers are never priority boosted unless they were * That said, RCU readers are never priority boosted unless they were
* preempted. Therefore, one way to avoid deadlock is to make sure * preempted. Therefore, one way to avoid deadlock is to make sure
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