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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2011-12-09 14:00:06 -0800
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2011-12-11 10:33:18 -0800
commit70321d447aa1a7cc2d60db16234f43c5a65630e7 (patch)
treea97749ef35045fc41585d121f595cb0644b319c2
parentd493011a376f9df3b8b3da1102509b343b1a4ef2 (diff)
Revert "rcu: Permit rt_mutex_unlock() with irqs disabled"
This reverts commit 5342e269b2b58ee0b0b4168a94087faaa60d0567. 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>
-rw-r--r--kernel/rcutree_plugin.h5
-rw-r--r--kernel/rtmutex.c8
2 files changed, 0 insertions, 13 deletions
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 8cd9efe7e81f..f55f10ba01f5 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -1165,8 +1165,6 @@ static void rcu_initiate_boost_trace(struct rcu_node *rnp)
#endif /* #else #ifdef CONFIG_RCU_TRACE */
-static struct lock_class_key rcu_boost_class;
-
/*
* Carry out RCU priority boosting on the task indicated by ->exp_tasks
* or ->boost_tasks, advancing the pointer to the next task in the
@@ -1229,9 +1227,6 @@ static int rcu_boost(struct rcu_node *rnp)
*/
t = container_of(tb, struct task_struct, rcu_node_entry);
rt_mutex_init_proxy_locked(&mtx, t);
- /* Avoid lockdep false positives. This rt_mutex is its own thing. */
- lockdep_set_class_and_name(&mtx.wait_lock, &rcu_boost_class,
- "rcu_boost_mutex");
t->rcu_boost_mutex = &mtx;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
rt_mutex_lock(&mtx); /* Side effect: boosts task t's priority. */
diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index f9d8482dd487..a242e691c993 100644
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -579,7 +579,6 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
struct rt_mutex_waiter *waiter)
{
int ret = 0;
- int was_disabled;
for (;;) {
/* Try to acquire the lock: */
@@ -602,17 +601,10 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
raw_spin_unlock(&lock->wait_lock);
- was_disabled = irqs_disabled();
- if (was_disabled)
- local_irq_enable();
-
debug_rt_mutex_print_deadlock(waiter);
schedule_rt_mutex(lock);
- if (was_disabled)
- local_irq_disable();
-
raw_spin_lock(&lock->wait_lock);
set_current_state(state);
}