1 files changed, 59 insertions, 114 deletions

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index f7ab703285a6..dc78956ccf03 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -55,6 +55,7 @@ struct cpu_workqueue_struct {
         struct list_head worklist;
         wait_queue_head_t more_work;
         struct work_struct *current_work;
+        unsigned int            cpu;
 
         struct workqueue_struct *wq;            /* I: the owning workqueue */
         struct task_struct      *thread;
@@ -189,34 +190,19 @@ static DEFINE_SPINLOCK(workqueue_lock);
 static LIST_HEAD(workqueues);
 
 static int singlethread_cpu __read_mostly;
-static const struct cpumask *cpu_singlethread_map __read_mostly;
-/*
- * _cpu_down() first removes CPU from cpu_online_map, then CPU_DEAD
- * flushes cwq->worklist. This means that flush_workqueue/wait_on_work
- * which comes in between can't use for_each_online_cpu(). We could
- * use cpu_possible_map, the cpumask below is more a documentation
- * than optimization.
- */
-static cpumask_var_t cpu_populated_map __read_mostly;
-
-/* If it's single threaded, it isn't in the list of workqueues. */
-static inline bool is_wq_single_threaded(struct workqueue_struct *wq)
-{
-        return wq->flags & WQ_SINGLE_THREAD;
-}
 
-static const struct cpumask *wq_cpu_map(struct workqueue_struct *wq)
+static struct cpu_workqueue_struct *get_cwq(unsigned int cpu,
+                                            struct workqueue_struct *wq)
 {
-        return is_wq_single_threaded(wq)
-                ? cpu_singlethread_map : cpu_populated_map;
+        return per_cpu_ptr(wq->cpu_wq, cpu);
 }
 
-static struct cpu_workqueue_struct *get_cwq(unsigned int cpu,
-                                            struct workqueue_struct *wq)
+static struct cpu_workqueue_struct *target_cwq(unsigned int cpu,
+                                               struct workqueue_struct *wq)
 {
-        if (unlikely(is_wq_single_threaded(wq)))
+        if (unlikely(wq->flags & WQ_SINGLE_THREAD))
                 cpu = singlethread_cpu;
-        return per_cpu_ptr(wq->cpu_wq, cpu);
+        return get_cwq(cpu, wq);
 }
 
 /*
@@ -279,7 +265,7 @@ static void insert_work(struct cpu_workqueue_struct *cwq,
 static void __queue_work(unsigned int cpu, struct workqueue_struct *wq,
                          struct work_struct *work)
 {
-        struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+        struct cpu_workqueue_struct *cwq = target_cwq(cpu, wq);
         unsigned long flags;
 
         debug_work_activate(work);
@@ -383,7 +369,7 @@ int queue_delayed_work_on(int cpu, struct workqueue_struct *wq,
                 timer_stats_timer_set_start_info(&dwork->timer);
 
                 /* This stores cwq for the moment, for the timer_fn */
-                set_wq_data(work, get_cwq(raw_smp_processor_id(), wq), 0);
+                set_wq_data(work, target_cwq(raw_smp_processor_id(), wq), 0);
                 timer->expires = jiffies + delay;
                 timer->data = (unsigned long)dwork;
                 timer->function = delayed_work_timer_fn;
@@ -495,6 +481,10 @@ static int worker_thread(void *__cwq)
                 if (kthread_should_stop())
                         break;
 
+                if (unlikely(!cpumask_equal(&cwq->thread->cpus_allowed,
+                                            get_cpu_mask(cwq->cpu))))
+                        set_cpus_allowed_ptr(cwq->thread,
+                                             get_cpu_mask(cwq->cpu));
                 run_workqueue(cwq);
         }
 
@@ -574,14 +564,13 @@ static int flush_cpu_workqueue(struct cpu_workqueue_struct *cwq)
  */
 void flush_workqueue(struct workqueue_struct *wq)
 {
-        const struct cpumask *cpu_map = wq_cpu_map(wq);
         int cpu;
 
         might_sleep();
         lock_map_acquire(&wq->lockdep_map);
         lock_map_release(&wq->lockdep_map);
-        for_each_cpu(cpu, cpu_map)
-                flush_cpu_workqueue(per_cpu_ptr(wq->cpu_wq, cpu));
+        for_each_possible_cpu(cpu)
+                flush_cpu_workqueue(get_cwq(cpu, wq));
 }
 EXPORT_SYMBOL_GPL(flush_workqueue);
 
@@ -699,7 +688,6 @@ static void wait_on_work(struct work_struct *work)
 {
         struct cpu_workqueue_struct *cwq;
         struct workqueue_struct *wq;
-        const struct cpumask *cpu_map;
         int cpu;
 
         might_sleep();
@@ -712,9 +700,8 @@ static void wait_on_work(struct work_struct *work)
                 return;
 
         wq = cwq->wq;
-        cpu_map = wq_cpu_map(wq);
 
-        for_each_cpu(cpu, cpu_map)
+        for_each_possible_cpu(cpu)
                 wait_on_cpu_work(get_cwq(cpu, wq), work);
 }
 
@@ -972,7 +959,7 @@ int current_is_keventd(void)
 
         BUG_ON(!keventd_wq);
 
-        cwq = per_cpu_ptr(keventd_wq->cpu_wq, cpu);
+        cwq = get_cwq(cpu, keventd_wq);
         if (current == cwq->thread)
                 ret = 1;
 
@@ -980,26 +967,12 @@ int current_is_keventd(void)
 
 }
 
-static struct cpu_workqueue_struct *
-init_cpu_workqueue(struct workqueue_struct *wq, int cpu)
-{
-        struct cpu_workqueue_struct *cwq = per_cpu_ptr(wq->cpu_wq, cpu);
-
-        cwq->wq = wq;
-        spin_lock_init(&cwq->lock);
-        INIT_LIST_HEAD(&cwq->worklist);
-        init_waitqueue_head(&cwq->more_work);
-
-        return cwq;
-}
-
 static int create_workqueue_thread(struct cpu_workqueue_struct *cwq, int cpu)
 {
         struct workqueue_struct *wq = cwq->wq;
-        const char *fmt = is_wq_single_threaded(wq) ? "%s" : "%s/%d";
         struct task_struct *p;
 
-        p = kthread_create(worker_thread, cwq, fmt, wq->name, cpu);
+        p = kthread_create(worker_thread, cwq, "%s/%d", wq->name, cpu);
         /*
          * Nobody can add the work_struct to this cwq,
          *      if (caller is __create_workqueue)
@@ -1031,8 +1004,8 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
                                                 struct lock_class_key *key,
                                                 const char *lock_name)
 {
+        bool singlethread = flags & WQ_SINGLE_THREAD;
         struct workqueue_struct *wq;
-        struct cpu_workqueue_struct *cwq;
         int err = 0, cpu;
 
         wq = kzalloc(sizeof(*wq), GFP_KERNEL);
@@ -1048,37 +1021,37 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
         lockdep_init_map(&wq->lockdep_map, lock_name, key, 0);
         INIT_LIST_HEAD(&wq->list);
 
-        if (flags & WQ_SINGLE_THREAD) {
-                cwq = init_cpu_workqueue(wq, singlethread_cpu);
-                err = create_workqueue_thread(cwq, singlethread_cpu);
-                start_workqueue_thread(cwq, -1);
-        } else {
-                cpu_maps_update_begin();
-                /*
-                 * We must place this wq on list even if the code below fails.
-                 * cpu_down(cpu) can remove cpu from cpu_populated_map before
-                 * destroy_workqueue() takes the lock, in that case we leak
-                 * cwq[cpu]->thread.
-                 */
-                spin_lock(&workqueue_lock);
-                list_add(&wq->list, &workqueues);
-                spin_unlock(&workqueue_lock);
-                /*
-                 * We must initialize cwqs for each possible cpu even if we
-                 * are going to call destroy_workqueue() finally. Otherwise
-                 * cpu_up() can hit the uninitialized cwq once we drop the
-                 * lock.
-                 */
-                for_each_possible_cpu(cpu) {
-                        cwq = init_cpu_workqueue(wq, cpu);
-                        if (err || !cpu_online(cpu))
-                                continue;
-                        err = create_workqueue_thread(cwq, cpu);
+        cpu_maps_update_begin();
+        /*
+         * We must initialize cwqs for each possible cpu even if we
+         * are going to call destroy_workqueue() finally. Otherwise
+         * cpu_up() can hit the uninitialized cwq once we drop the
+         * lock.
+         */
+        for_each_possible_cpu(cpu) {
+                struct cpu_workqueue_struct *cwq = get_cwq(cpu, wq);
+
+                cwq->wq = wq;
+                cwq->cpu = cpu;
+                spin_lock_init(&cwq->lock);
+                INIT_LIST_HEAD(&cwq->worklist);
+                init_waitqueue_head(&cwq->more_work);
+
+                if (err)
+                        continue;
+                err = create_workqueue_thread(cwq, cpu);
+                if (cpu_online(cpu) && !singlethread)
                         start_workqueue_thread(cwq, cpu);
-                }
-                cpu_maps_update_done();
+                else
+                        start_workqueue_thread(cwq, -1);
         }
 
+        spin_lock(&workqueue_lock);
+        list_add(&wq->list, &workqueues);
+        spin_unlock(&workqueue_lock);
+
+        cpu_maps_update_done();
+
         if (err) {
                 destroy_workqueue(wq);
                 wq = NULL;
@@ -1128,17 +1101,16 @@ static void cleanup_workqueue_thread(struct cpu_workqueue_struct *cwq)
  */
 void destroy_workqueue(struct workqueue_struct *wq)
 {
-        const struct cpumask *cpu_map = wq_cpu_map(wq);
         int cpu;
 
         cpu_maps_update_begin();
         spin_lock(&workqueue_lock);
         list_del(&wq->list);
         spin_unlock(&workqueue_lock);
+        cpu_maps_update_done();
 
-        for_each_cpu(cpu, cpu_map)
-                cleanup_workqueue_thread(per_cpu_ptr(wq->cpu_wq, cpu));
-        cpu_maps_update_done();
+        for_each_possible_cpu(cpu)
+                cleanup_workqueue_thread(get_cwq(cpu, wq));
 
         free_percpu(wq->cpu_wq);
         kfree(wq);
@@ -1152,48 +1124,25 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
         unsigned int cpu = (unsigned long)hcpu;
         struct cpu_workqueue_struct *cwq;
         struct workqueue_struct *wq;
-        int err = 0;
 
         action &= ~CPU_TASKS_FROZEN;
 
-        switch (action) {
-        case CPU_UP_PREPARE:
-                cpumask_set_cpu(cpu, cpu_populated_map);
-        }
-undo:
         list_for_each_entry(wq, &workqueues, list) {
-                cwq = per_cpu_ptr(wq->cpu_wq, cpu);
+                if (wq->flags & WQ_SINGLE_THREAD)
+                        continue;
 
-                switch (action) {
-                case CPU_UP_PREPARE:
-                        err = create_workqueue_thread(cwq, cpu);
-                        if (!err)
-                                break;
-                        printk(KERN_ERR "workqueue [%s] for %i failed\n",
-                                wq->name, cpu);
-                        action = CPU_UP_CANCELED;
-                        err = -ENOMEM;
-                        goto undo;
-
-                case CPU_ONLINE:
-                        start_workqueue_thread(cwq, cpu);
-                        break;
+                cwq = get_cwq(cpu, wq);
 
-                case CPU_UP_CANCELED:
-                        start_workqueue_thread(cwq, -1);
+                switch (action) {
                 case CPU_POST_DEAD:
-                        cleanup_workqueue_thread(cwq);
+                        lock_map_acquire(&cwq->wq->lockdep_map);
+                        lock_map_release(&cwq->wq->lockdep_map);
+                        flush_cpu_workqueue(cwq);
                         break;
                 }
         }
 
-        switch (action) {
-        case CPU_UP_CANCELED:
-        case CPU_POST_DEAD:
-                cpumask_clear_cpu(cpu, cpu_populated_map);
-        }
-
-        return notifier_from_errno(err);
+        return notifier_from_errno(0);
 }
 
 #ifdef CONFIG_SMP
@@ -1245,11 +1194,7 @@ EXPORT_SYMBOL_GPL(work_on_cpu);
 
 void __init init_workqueues(void)
 {
-        alloc_cpumask_var(&cpu_populated_map, GFP_KERNEL);
-
-        cpumask_copy(cpu_populated_map, cpu_online_mask);
         singlethread_cpu = cpumask_first(cpu_possible_mask);
-        cpu_singlethread_map = cpumask_of(singlethread_cpu);
         hotcpu_notifier(workqueue_cpu_callback, 0);
         keventd_wq = create_workqueue("events");
         BUG_ON(!keventd_wq);