2 files changed, 8 insertions, 9 deletions

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 8154a4a3491c..5d96d68d20f8 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -36,7 +36,7 @@
 #include <linux/interrupt.h>
 #include <linux/sched.h>
 #include <linux/nmi.h>
-#include <asm/atomic.h>
+#include <linux/atomic.h>
 #include <linux/bitops.h>
 #include <linux/module.h>
 #include <linux/completion.h>
@@ -1526,13 +1526,10 @@ static void rcu_cpu_kthread_setrt(int cpu, int to_rt)
  */
 static void rcu_cpu_kthread_timer(unsigned long arg)
 {
-        unsigned long flags;
         struct rcu_data *rdp = per_cpu_ptr(rcu_state->rda, arg);
         struct rcu_node *rnp = rdp->mynode;
 
-        raw_spin_lock_irqsave(&rnp->lock, flags);
-        rnp->wakemask |= rdp->grpmask;
-        raw_spin_unlock_irqrestore(&rnp->lock, flags);
+        atomic_or(rdp->grpmask, &rnp->wakemask);
         invoke_rcu_node_kthread(rnp);
 }
 
@@ -1680,11 +1677,11 @@ static int rcu_node_kthread(void *arg)
 
         for (;;) {
                 rnp->node_kthread_status = RCU_KTHREAD_WAITING;
-                wait_event_interruptible(rnp->node_wq, rnp->wakemask != 0);
+                wait_event_interruptible(rnp->node_wq,
+                                         atomic_read(&rnp->wakemask) != 0);
                 rnp->node_kthread_status = RCU_KTHREAD_RUNNING;
                 raw_spin_lock_irqsave(&rnp->lock, flags);
-                mask = rnp->wakemask;
-                rnp->wakemask = 0;
+                mask = atomic_xchg(&rnp->wakemask, 0);
                 rcu_initiate_boost(rnp, flags); /* releases rnp->lock. */
                 for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask >>= 1) {
                         if ((mask & 0x1) == 0)
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index 93d4a1c2e88b..561dcb9a8d2c 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -119,7 +119,9 @@ struct rcu_node {
                                 /*  elements that need to drain to allow the */
                                 /*  current expedited grace period to */
                                 /*  complete (only for TREE_PREEMPT_RCU). */
-        unsigned long wakemask; /* CPUs whose kthread needs to be awakened. */
+        atomic_t wakemask;      /* CPUs whose kthread needs to be awakened. */
+                                /*  Since this has meaning only for leaf */
+                                /*  rcu_node structures, 32 bits suffices. */
         unsigned long qsmaskinit;
                                 /* Per-GP initial value for qsmask & expmask. */
         unsigned long grpmask;  /* Mask to apply to parent qsmask. */