1 files changed, 20 insertions, 19 deletions

diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 1a74cf7415c0..bb4b441b1860 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -517,8 +517,9 @@ extern void __send_remote_softirq(struct call_single_data *cp, int cpu,
      to be executed on some cpu at least once after this.
    * If the tasklet is already scheduled, but its execution is still not
      started, it will be executed only once.
-   * If this tasklet is already running on another CPU (or schedule is called
-     from tasklet itself), it is rescheduled for later.
+   * If this tasklet is already running on another CPU, it is rescheduled
+     for later.
+   * Schedule must not be called from the tasklet itself (a lockup occurs)
    * Tasklet is strictly serialized wrt itself, but not
      wrt another tasklets. If client needs some intertask synchronization,
      he makes it with spinlocks.
@@ -543,27 +544,36 @@ struct tasklet_struct name = { NULL, 0, ATOMIC_INIT(1), func, data }
 enum
 {
 	TASKLET_STATE_SCHED,	/* Tasklet is scheduled for execution */
-	TASKLET_STATE_RUN	/* Tasklet is running (SMP only) */
+	TASKLET_STATE_RUN,	/* Tasklet is running (SMP only) */
+	TASKLET_STATE_PENDING	/* Tasklet is pending */
 };
 
-#ifdef CONFIG_SMP
+#define TASKLET_STATEF_SCHED	(1 << TASKLET_STATE_SCHED)
+#define TASKLET_STATEF_RUN	(1 << TASKLET_STATE_RUN)
+#define TASKLET_STATEF_PENDING	(1 << TASKLET_STATE_PENDING)
+
+#if defined(CONFIG_SMP) || defined(CONFIG_PREEMPT_RT_FULL)
 static inline int tasklet_trylock(struct tasklet_struct *t)
 {
 	return !test_and_set_bit(TASKLET_STATE_RUN, &(t)->state);
 }
 
+static inline int tasklet_tryunlock(struct tasklet_struct *t)
+{
+	return cmpxchg(&t->state, TASKLET_STATEF_RUN, 0) == TASKLET_STATEF_RUN;
+}
+
 static inline void tasklet_unlock(struct tasklet_struct *t)
 {
 	smp_mb__before_clear_bit(); 
 	clear_bit(TASKLET_STATE_RUN, &(t)->state);
 }
 
-static inline void tasklet_unlock_wait(struct tasklet_struct *t)
-{
-	while (test_bit(TASKLET_STATE_RUN, &(t)->state)) { barrier(); }
-}
+extern void tasklet_unlock_wait(struct tasklet_struct *t);
+
 #else
 #define tasklet_trylock(t) 1
+#define tasklet_tryunlock(t)	1
 #define tasklet_unlock_wait(t) do { } while (0)
 #define tasklet_unlock(t) do { } while (0)
 #endif
@@ -612,17 +622,8 @@ static inline void tasklet_disable(struct tasklet_struct *t)
 	smp_mb();
 }
 
-static inline void tasklet_enable(struct tasklet_struct *t)
-{
-	smp_mb__before_atomic_dec();
-	atomic_dec(&t->count);
-}
-
-static inline void tasklet_hi_enable(struct tasklet_struct *t)
-{
-	smp_mb__before_atomic_dec();
-	atomic_dec(&t->count);
-}
+extern  void tasklet_enable(struct tasklet_struct *t);
+extern  void tasklet_hi_enable(struct tasklet_struct *t);
 
 extern void tasklet_kill(struct tasklet_struct *t);
 extern void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu);