1 files changed, 33 insertions, 20 deletions

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 7717b95c2027..f3e43274ed53 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1325,22 +1325,40 @@ int rcu_needs_cpu(int cpu)
 }
 
 /*
- * Initialize a CPU's per-CPU RCU data.  We take this "scorched earth"
- * approach so that we don't have to worry about how long the CPU has
- * been gone, or whether it ever was online previously.  We do trust the
- * ->mynode field, as it is constant for a given struct rcu_data and
- * initialized during early boot.
- *
- * Note that only one online or offline event can be happening at a given
- * time.  Note also that we can accept some slop in the rsp->completed
- * access due to the fact that this CPU cannot possibly have any RCU
- * callbacks in flight yet.
+ * Do boot-time initialization of a CPU's per-CPU RCU data.
+ */
+static void __init
+rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
+{
+        unsigned long flags;
+        int i;
+        struct rcu_data *rdp = rsp->rda[cpu];
+        struct rcu_node *rnp = rcu_get_root(rsp);
+
+        /* Set up local state, ensuring consistent view of global state. */
+        spin_lock_irqsave(&rnp->lock, flags);
+        rdp->grpmask = 1UL << (cpu - rdp->mynode->grplo);
+        rdp->nxtlist = NULL;
+        for (i = 0; i < RCU_NEXT_SIZE; i++)
+                rdp->nxttail[i] = &rdp->nxtlist;
+        rdp->qlen = 0;
+#ifdef CONFIG_NO_HZ
+        rdp->dynticks = &per_cpu(rcu_dynticks, cpu);
+#endif /* #ifdef CONFIG_NO_HZ */
+        rdp->cpu = cpu;
+        spin_unlock_irqrestore(&rnp->lock, flags);
+}
+
+/*
+ * Initialize a CPU's per-CPU RCU data.  Note that only one online or
+ * offline event can be happening at a given time.  Note also that we
+ * can accept some slop in the rsp->completed access due to the fact
+ * that this CPU cannot possibly have any RCU callbacks in flight yet.
  */
 static void __cpuinit
 rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
 {
         unsigned long flags;
-        int i;
         long lastcomp;
         unsigned long mask;
         struct rcu_data *rdp = rsp->rda[cpu];
@@ -1355,16 +1373,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
         rdp->qs_pending = 1;     /*  so set up to respond to current GP. */
         rdp->beenonline = 1;     /* We have now been online. */
         rdp->passed_quiesc_completed = lastcomp - 1;
-        rdp->grpmask = 1UL << (cpu - rdp->mynode->grplo);
-        rdp->nxtlist = NULL;
-        for (i = 0; i < RCU_NEXT_SIZE; i++)
-                rdp->nxttail[i] = &rdp->nxtlist;
-        rdp->qlen = 0;
         rdp->blimit = blimit;
-#ifdef CONFIG_NO_HZ
-        rdp->dynticks = &per_cpu(rcu_dynticks, cpu);
-#endif /* #ifdef CONFIG_NO_HZ */
-        rdp->cpu = cpu;
         spin_unlock(&rnp->lock);                /* irqs remain disabled. */
 
         /*
@@ -1539,8 +1548,12 @@ void __init __rcu_init(void)
 #endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
         rcu_init_one(&rcu_state);
         RCU_DATA_PTR_INIT(&rcu_state, rcu_data);
+        for_each_possible_cpu(i)
+                rcu_boot_init_percpu_data(i, &rcu_state);
         rcu_init_one(&rcu_bh_state);
         RCU_DATA_PTR_INIT(&rcu_bh_state, rcu_bh_data);
+        for_each_possible_cpu(i)
+                rcu_boot_init_percpu_data(i, &rcu_bh_state);
 
         for_each_online_cpu(i)
                 rcu_cpu_notify(&rcu_nb, CPU_UP_PREPARE, (void *)(long)i);