Merge branch 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull smp hotplug updates from Thomas Gleixner:
 "This is the next part of the hotplug rework.

   - Convert all notifiers with a priority assigned

   - Convert all CPU_STARTING/DYING notifiers

     The final removal of the STARTING/DYING infrastructure will happen
     when the merge window closes.

  Another 700 hundred line of unpenetrable maze gone :)"

* 'smp-hotplug-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (70 commits)
  timers/core: Correct callback order during CPU hot plug
  leds/trigger/cpu: Move from CPU_STARTING to ONLINE level
  powerpc/numa: Convert to hotplug state machine
  arm/perf: Fix hotplug state machine conversion
  irqchip/armada: Avoid unused function warnings
  ARC/time: Convert to hotplug state machine
  clocksource/atlas7: Convert to hotplug state machine
  clocksource/armada-370-xp: Convert to hotplug state machine
  clocksource/exynos_mct: Convert to hotplug state machine
  clocksource/arm_global_timer: Convert to hotplug state machine
  rcu: Convert rcutree to hotplug state machine
  KVM/arm/arm64/vgic-new: Convert to hotplug state machine
  smp/cfd: Convert core to hotplug state machine
  x86/x2apic: Convert to CPU hotplug state machine
  profile: Convert to hotplug state machine
  timers/core: Convert to hotplug state machine
  hrtimer: Convert to hotplug state machine
  x86/tboot: Convert to hotplug state machine
  arm64/armv8 deprecated: Convert to hotplug state machine
  hwtracing/coresight-etm4x: Convert to hotplug state machine
  ...

1 files changed, 43 insertions, 65 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index d12bd958077e..ef071ca73fc3 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -4607,84 +4607,65 @@ static void restore_unbound_workers_cpumask(struct worker_pool *pool, int cpu)
                 WARN_ON_ONCE(set_cpus_allowed_ptr(worker->task, &cpumask) < 0);
 }
 
-/*
- * Workqueues should be brought up before normal priority CPU notifiers.
- * This will be registered high priority CPU notifier.
- */
-static int workqueue_cpu_up_callback(struct notifier_block *nfb,
-                                               unsigned long action,
-                                               void *hcpu)
+int workqueue_prepare_cpu(unsigned int cpu)
+{
+        struct worker_pool *pool;
+
+        for_each_cpu_worker_pool(pool, cpu) {
+                if (pool->nr_workers)
+                        continue;
+                if (!create_worker(pool))
+                        return -ENOMEM;
+        }
+        return 0;
+}
+
+int workqueue_online_cpu(unsigned int cpu)
 {
-        int cpu = (unsigned long)hcpu;
         struct worker_pool *pool;
         struct workqueue_struct *wq;
         int pi;
 
-        switch (action & ~CPU_TASKS_FROZEN) {
-        case CPU_UP_PREPARE:
-                for_each_cpu_worker_pool(pool, cpu) {
-                        if (pool->nr_workers)
-                                continue;
-                        if (!create_worker(pool))
-                                return NOTIFY_BAD;
-                }
-                break;
-
-        case CPU_DOWN_FAILED:
-        case CPU_ONLINE:
-                mutex_lock(&wq_pool_mutex);
+        mutex_lock(&wq_pool_mutex);
 
-                for_each_pool(pool, pi) {
-                        mutex_lock(&pool->attach_mutex);
+        for_each_pool(pool, pi) {
+                mutex_lock(&pool->attach_mutex);
 
-                        if (pool->cpu == cpu)
-                                rebind_workers(pool);
-                        else if (pool->cpu < 0)
-                                restore_unbound_workers_cpumask(pool, cpu);
+                if (pool->cpu == cpu)
+                        rebind_workers(pool);
+                else if (pool->cpu < 0)
+                        restore_unbound_workers_cpumask(pool, cpu);
 
-                        mutex_unlock(&pool->attach_mutex);
-                }
+                mutex_unlock(&pool->attach_mutex);
+        }
 
-                /* update NUMA affinity of unbound workqueues */
-                list_for_each_entry(wq, &workqueues, list)
-                        wq_update_unbound_numa(wq, cpu, true);
+        /* update NUMA affinity of unbound workqueues */
+        list_for_each_entry(wq, &workqueues, list)
+                wq_update_unbound_numa(wq, cpu, true);
 
-                mutex_unlock(&wq_pool_mutex);
-                break;
-        }
-        return NOTIFY_OK;
+        mutex_unlock(&wq_pool_mutex);
+        return 0;
 }
 
-/*
- * Workqueues should be brought down after normal priority CPU notifiers.
- * This will be registered as low priority CPU notifier.
- */
-static int workqueue_cpu_down_callback(struct notifier_block *nfb,
-                                                 unsigned long action,
-                                                 void *hcpu)
+int workqueue_offline_cpu(unsigned int cpu)
 {
-        int cpu = (unsigned long)hcpu;
         struct work_struct unbind_work;
         struct workqueue_struct *wq;
 
-        switch (action & ~CPU_TASKS_FROZEN) {
-        case CPU_DOWN_PREPARE:
-                /* unbinding per-cpu workers should happen on the local CPU */
-                INIT_WORK_ONSTACK(&unbind_work, wq_unbind_fn);
-                queue_work_on(cpu, system_highpri_wq, &unbind_work);
-
-                /* update NUMA affinity of unbound workqueues */
-                mutex_lock(&wq_pool_mutex);
-                list_for_each_entry(wq, &workqueues, list)
-                        wq_update_unbound_numa(wq, cpu, false);
-                mutex_unlock(&wq_pool_mutex);
-
-                /* wait for per-cpu unbinding to finish */
-                flush_work(&unbind_work);
-                destroy_work_on_stack(&unbind_work);
-                break;
-        }
-        return NOTIFY_OK;
+        /* unbinding per-cpu workers should happen on the local CPU */
+        INIT_WORK_ONSTACK(&unbind_work, wq_unbind_fn);
+        queue_work_on(cpu, system_highpri_wq, &unbind_work);
+
+        /* update NUMA affinity of unbound workqueues */
+        mutex_lock(&wq_pool_mutex);
+        list_for_each_entry(wq, &workqueues, list)
+                wq_update_unbound_numa(wq, cpu, false);
+        mutex_unlock(&wq_pool_mutex);
+
+        /* wait for per-cpu unbinding to finish */
+        flush_work(&unbind_work);
+        destroy_work_on_stack(&unbind_work);
+        return 0;
 }
 
 #ifdef CONFIG_SMP
@@ -5486,9 +5467,6 @@ static int __init init_workqueues(void)
 
         pwq_cache = KMEM_CACHE(pool_workqueue, SLAB_PANIC);
 
-        cpu_notifier(workqueue_cpu_up_callback, CPU_PRI_WORKQUEUE_UP);
-        hotcpu_notifier(workqueue_cpu_down_callback, CPU_PRI_WORKQUEUE_DOWN);
-
         wq_numa_init();
 
         /* initialize CPU pools */