Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-3.0-nmw

[firefly-linux-kernel-4.4.55.git] / kernel / rcutiny_plugin.h

diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index b58a3200f0ff0948b48329aeb7c999d4523abac8..22ecea0dfb62575d14fafb8e5776a11d21f309f9 100644 (file)
--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -318,7 +318,6 @@ static int rcu_boost(void)
        t = container_of(tb, struct task_struct, rcu_node_entry);
        rt_mutex_init_proxy_locked(&mtx, t);
        t->rcu_boost_mutex = &mtx;
-       t->rcu_read_unlock_special |= RCU_READ_UNLOCK_BOOSTED;
        raw_local_irq_restore(flags);
        rt_mutex_lock(&mtx);
        rt_mutex_unlock(&mtx);  /* Keep lockdep happy. */
@@ -550,6 +549,9 @@ static noinline void rcu_read_unlock_special(struct task_struct *t)
        int empty_exp;
        unsigned long flags;
        struct list_head *np;
+#ifdef CONFIG_RCU_BOOST
+       struct rt_mutex *rbmp = NULL;
+#endif /* #ifdef CONFIG_RCU_BOOST */
        int special;
 
        /*
@@ -570,7 +572,7 @@ static noinline void rcu_read_unlock_special(struct task_struct *t)
                rcu_preempt_cpu_qs();
 
        /* Hardware IRQ handlers cannot block. */
-       if (in_irq()) {
+       if (in_irq() || in_serving_softirq()) {
                local_irq_restore(flags);
                return;
        }
@@ -615,10 +617,10 @@ static noinline void rcu_read_unlock_special(struct task_struct *t)
        }
 #ifdef CONFIG_RCU_BOOST
        /* Unboost self if was boosted. */
-       if (special & RCU_READ_UNLOCK_BOOSTED) {
-               t->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_BOOSTED;
-               rt_mutex_unlock(t->rcu_boost_mutex);
+       if (t->rcu_boost_mutex != NULL) {
+               rbmp = t->rcu_boost_mutex;
                t->rcu_boost_mutex = NULL;
+               rt_mutex_unlock(rbmp);
        }
 #endif /* #ifdef CONFIG_RCU_BOOST */
        local_irq_restore(flags);
@@ -914,7 +916,8 @@ static void rcu_preempt_process_callbacks(void)
 static void invoke_rcu_callbacks(void)
 {
        have_rcu_kthread_work = 1;
-       wake_up(&rcu_kthread_wq);
+       if (rcu_kthread_task != NULL)
+               wake_up(&rcu_kthread_wq);
 }
 
 #ifdef CONFIG_RCU_TRACE
@@ -975,12 +978,16 @@ early_initcall(rcu_spawn_kthreads);
 
 #else /* #ifdef CONFIG_RCU_BOOST */
 
+/* Hold off callback invocation until early_initcall() time. */
+static int rcu_scheduler_fully_active __read_mostly;
+
 /*
  * Start up softirq processing of callbacks.
  */
 void invoke_rcu_callbacks(void)
 {
-       raise_softirq(RCU_SOFTIRQ);
+       if (rcu_scheduler_fully_active)
+               raise_softirq(RCU_SOFTIRQ);
 }
 
 #ifdef CONFIG_RCU_TRACE
@@ -995,10 +1002,14 @@ static bool rcu_is_callbacks_kthread(void)
 
 #endif /* #ifdef CONFIG_RCU_TRACE */
 
-void rcu_init(void)
+static int __init rcu_scheduler_really_started(void)
 {
+       rcu_scheduler_fully_active = 1;
        open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
+       raise_softirq(RCU_SOFTIRQ);  /* Invoke any callbacks from early boot. */
+       return 0;
 }
+early_initcall(rcu_scheduler_really_started);
 
 #endif /* #else #ifdef CONFIG_RCU_BOOST */