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>

1 files changed, 0 insertions, 8 deletions

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);
         }