rtmutex: Handle deadlock detection smarter

[GitHub/mt8127/android_kernel_alcatel_ttab.git] / kernel / rtmutex.c

diff --git a/kernel/rtmutex.c b/kernel/rtmutex.c
index 4b0fba9bacc126764e3c4772e7421b1417431326..18dfeeb0dafaa4ce5abfacdb87ca7a2974ee4179 100644 (file)
--- a/kernel/rtmutex.c
+++ b/kernel/rtmutex.c
@@ -189,7 +189,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
                }
                put_task_struct(task);
 
-               return deadlock_detect ? -EDEADLK : 0;
+               return -EDEADLK;
        }
  retry:
        /*
@@ -264,7 +264,7 @@ static int rt_mutex_adjust_prio_chain(struct task_struct *task,
        if (lock == orig_lock || rt_mutex_owner(lock) == top_task) {
                debug_rt_mutex_deadlock(deadlock_detect, orig_waiter, lock);
                raw_spin_unlock(&lock->wait_lock);
-               ret = deadlock_detect ? -EDEADLK : 0;
+               ret = -EDEADLK;
                goto out_unlock_pi;
        }
 
@@ -454,7 +454,7 @@ static int task_blocks_on_rt_mutex(struct rt_mutex *lock,
         * which is wrong, as the other waiter is not in a deadlock
         * situation.
         */
-       if (detect_deadlock && owner == task)
+       if (owner == task)
                return -EDEADLK;
 
        raw_spin_lock_irqsave(&task->pi_lock, flags);
@@ -681,6 +681,26 @@ __rt_mutex_slowlock(struct rt_mutex *lock, int state,
        return ret;
 }
 
+static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
+                                    struct rt_mutex_waiter *w)
+{
+       /*
+        * If the result is not -EDEADLOCK or the caller requested
+        * deadlock detection, nothing to do here.
+        */
+       if (res != -EDEADLOCK || detect_deadlock)
+               return;
+
+       /*
+        * Yell lowdly and stop the task right here.
+        */
+       rt_mutex_print_deadlock(w);
+       while (1) {
+               set_current_state(TASK_INTERRUPTIBLE);
+               schedule();
+       }
+}
+
 /*
  * Slow path lock function:
  */
@@ -718,8 +738,10 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
 
        set_current_state(TASK_RUNNING);
 
-       if (unlikely(ret))
+       if (unlikely(ret)) {
                remove_waiter(lock, &waiter);
+               rt_mutex_handle_deadlock(ret, detect_deadlock, &waiter);
+       }
 
        /*
         * try_to_take_rt_mutex() sets the waiter bit
@@ -1027,7 +1049,8 @@ int rt_mutex_start_proxy_lock(struct rt_mutex *lock,
                return 1;
        }
 
-       ret = task_blocks_on_rt_mutex(lock, waiter, task, detect_deadlock);
+       /* We enforce deadlock detection for futexes */
+       ret = task_blocks_on_rt_mutex(lock, waiter, task, 1);
 
        if (ret && !rt_mutex_owner(lock)) {
                /*