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Revert "rcu: Permit rt_mutex_unlock() with irqs disabled"
This reverts commit 5342e269b2
.
The approach taken in this patch was deemed too abusive to mutexes,
and thus too likely to result in maintenance problems in the future.
Instead, we will disallow RCU read-side critical sections that partially
overlap with interrupt-disbled code segments.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
parent
d493011a37
commit
70321d447a
@ -1165,8 +1165,6 @@ static void rcu_initiate_boost_trace(struct rcu_node *rnp)
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#endif /* #else #ifdef CONFIG_RCU_TRACE */
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static struct lock_class_key rcu_boost_class;
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/*
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* Carry out RCU priority boosting on the task indicated by ->exp_tasks
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* or ->boost_tasks, advancing the pointer to the next task in the
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@ -1229,9 +1227,6 @@ static int rcu_boost(struct rcu_node *rnp)
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*/
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t = container_of(tb, struct task_struct, rcu_node_entry);
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rt_mutex_init_proxy_locked(&mtx, t);
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/* Avoid lockdep false positives. This rt_mutex is its own thing. */
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lockdep_set_class_and_name(&mtx.wait_lock, &rcu_boost_class,
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"rcu_boost_mutex");
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t->rcu_boost_mutex = &mtx;
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raw_spin_unlock_irqrestore(&rnp->lock, flags);
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rt_mutex_lock(&mtx); /* Side effect: boosts task t's priority. */
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@ -579,7 +579,6 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
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struct rt_mutex_waiter *waiter)
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{
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int ret = 0;
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int was_disabled;
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for (;;) {
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/* Try to acquire the lock: */
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@ -602,17 +601,10 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
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raw_spin_unlock(&lock->wait_lock);
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was_disabled = irqs_disabled();
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if (was_disabled)
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local_irq_enable();
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debug_rt_mutex_print_deadlock(waiter);
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schedule_rt_mutex(lock);
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if (was_disabled)
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local_irq_disable();
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raw_spin_lock(&lock->wait_lock);
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set_current_state(state);
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}
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