vt: Deadlock workaround

[pandora-kernel.git] / kernel / workqueue.c

diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index fe08a85..4a26a13 100644 (file)
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -689,8 +689,7 @@ int schedule_on_each_cpu(work_func_t func)
                struct work_struct *work = per_cpu_ptr(works, cpu);
 
                INIT_WORK(work, func);
-               set_bit(WORK_STRUCT_PENDING, work_data_bits(work));
-               __queue_work(per_cpu_ptr(keventd_wq->cpu_wq, cpu), work);
+               schedule_work_on(cpu, work);
        }
        for_each_online_cpu(cpu)
                flush_work(per_cpu_ptr(works, cpu));
@@ -831,10 +830,21 @@ struct workqueue_struct *__create_workqueue_key(const char *name,
                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))
@@ -912,6 +922,7 @@ 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 ret = NOTIFY_OK;
 
        action &= ~CPU_TASKS_FROZEN;
 
@@ -919,7 +930,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
        case CPU_UP_PREPARE:
                cpu_set(cpu, cpu_populated_map);
        }
-
+undo:
        list_for_each_entry(wq, &workqueues, list) {
                cwq = per_cpu_ptr(wq->cpu_wq, cpu);
 
@@ -929,7 +940,9 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
                                break;
                        printk(KERN_ERR "workqueue [%s] for %i failed\n",
                                wq->name, cpu);
-                       return NOTIFY_BAD;
+                       action = CPU_UP_CANCELED;
+                       ret = NOTIFY_BAD;
+                       goto undo;
 
                case CPU_ONLINE:
                        start_workqueue_thread(cwq, cpu);
@@ -949,7 +962,7 @@ static int __devinit workqueue_cpu_callback(struct notifier_block *nfb,
                cpu_clear(cpu, cpu_populated_map);
        }
 
-       return NOTIFY_OK;
+       return ret;
 }
 
 void __init init_workqueues(void)