1 files changed, 28 insertions, 7 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 79a11e40f311..c11edc9c9365 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -186,6 +186,27 @@ struct wq_flusher {
 };
 
 /*
+ * All cpumasks are assumed to be always set on UP and thus can't be
+ * used to determine whether there's something to be done.
+ */
+#ifdef CONFIG_SMP
+typedef cpumask_var_t mayday_mask_t;
+#define mayday_test_and_set_cpu(cpu, mask)      \
+        cpumask_test_and_set_cpu((cpu), (mask))
+#define mayday_clear_cpu(cpu, mask)             cpumask_clear_cpu((cpu), (mask))
+#define for_each_mayday_cpu(cpu, mask)          for_each_cpu((cpu), (mask))
+#define alloc_mayday_mask(maskp, gfp)           alloc_cpumask_var((maskp), (gfp))
+#define free_mayday_mask(mask)                  free_cpumask_var((mask))
+#else
+typedef unsigned long mayday_mask_t;
+#define mayday_test_and_set_cpu(cpu, mask)      test_and_set_bit(0, &(mask))
+#define mayday_clear_cpu(cpu, mask)             clear_bit(0, &(mask))
+#define for_each_mayday_cpu(cpu, mask)          if ((cpu) = 0, (mask))
+#define alloc_mayday_mask(maskp, gfp)           true
+#define free_mayday_mask(mask)                  do { } while (0)
+#endif
+
+/*
  * The externally visible workqueue abstraction is an array of
  * per-CPU workqueues:
  */
@@ -206,7 +227,7 @@ struct workqueue_struct {
         struct list_head        flusher_queue;  /* F: flush waiters */
         struct list_head        flusher_overflow; /* F: flush overflow list */
 
-        cpumask_var_t           mayday_mask;    /* cpus requesting rescue */
+        mayday_mask_t           mayday_mask;    /* cpus requesting rescue */
         struct worker           *rescuer;       /* I: rescue worker */
 
         int                     saved_max_active; /* W: saved cwq max_active */
@@ -1387,7 +1408,7 @@ static bool send_mayday(struct work_struct *work)
         /* WORK_CPU_UNBOUND can't be set in cpumask, use cpu 0 instead */
         if (cpu == WORK_CPU_UNBOUND)
                 cpu = 0;
-        if (!cpumask_test_and_set_cpu(cpu, wq->mayday_mask))
+        if (!mayday_test_and_set_cpu(cpu, wq->mayday_mask))
                 wake_up_process(wq->rescuer->task);
         return true;
 }
@@ -1915,14 +1936,14 @@ repeat:
          * See whether any cpu is asking for help.  Unbounded
          * workqueues use cpu 0 in mayday_mask for CPU_UNBOUND.
          */
-        for_each_cpu(cpu, wq->mayday_mask) {
+        for_each_mayday_cpu(cpu, wq->mayday_mask) {
                 unsigned int tcpu = is_unbound ? WORK_CPU_UNBOUND : cpu;
                 struct cpu_workqueue_struct *cwq = get_cwq(tcpu, wq);
                 struct global_cwq *gcwq = cwq->gcwq;
                 struct work_struct *work, *n;
 
                 __set_current_state(TASK_RUNNING);
-                cpumask_clear_cpu(cpu, wq->mayday_mask);
+                mayday_clear_cpu(cpu, wq->mayday_mask);
 
                 /* migrate to the target cpu if possible */
                 rescuer->gcwq = gcwq;
@@ -2724,7 +2745,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *name,
         if (flags & WQ_RESCUER) {
                 struct worker *rescuer;
 
-                if (!alloc_cpumask_var(&wq->mayday_mask, GFP_KERNEL))
+                if (!alloc_mayday_mask(&wq->mayday_mask, GFP_KERNEL))
                         goto err;
 
                 wq->rescuer = rescuer = alloc_worker();
@@ -2759,7 +2780,7 @@ struct workqueue_struct *__alloc_workqueue_key(const char *name,
 err:
         if (wq) {
                 free_cwqs(wq);
-                free_cpumask_var(wq->mayday_mask);
+                free_mayday_mask(wq->mayday_mask);
                 kfree(wq->rescuer);
                 kfree(wq);
         }
@@ -2800,7 +2821,7 @@ void destroy_workqueue(struct workqueue_struct *wq)
 
         if (wq->flags & WQ_RESCUER) {
                 kthread_stop(wq->rescuer->task);
-                free_cpumask_var(wq->mayday_mask);
+                free_mayday_mask(wq->mayday_mask);
         }
 
         free_cwqs(wq);