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stop_machine: Use raw spinlocks
Use raw-locks in stop_machine() to allow locking in irq-off and preempt-disabled regions on -RT. This also documents the possible locking context in general. [bigeasy: update patch description.] Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Link: https://lkml.kernel.org/r/20180423191635.6014-1-bigeasy@linutronix.de
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@ -36,7 +36,7 @@ struct cpu_stop_done {
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struct cpu_stopper {
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struct task_struct *thread;
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spinlock_t lock;
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raw_spinlock_t lock;
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bool enabled; /* is this stopper enabled? */
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struct list_head works; /* list of pending works */
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@ -78,13 +78,13 @@ static bool cpu_stop_queue_work(unsigned int cpu, struct cpu_stop_work *work)
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unsigned long flags;
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bool enabled;
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spin_lock_irqsave(&stopper->lock, flags);
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raw_spin_lock_irqsave(&stopper->lock, flags);
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enabled = stopper->enabled;
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if (enabled)
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__cpu_stop_queue_work(stopper, work);
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else if (work->done)
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cpu_stop_signal_done(work->done);
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spin_unlock_irqrestore(&stopper->lock, flags);
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raw_spin_unlock_irqrestore(&stopper->lock, flags);
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return enabled;
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}
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@ -231,8 +231,8 @@ static int cpu_stop_queue_two_works(int cpu1, struct cpu_stop_work *work1,
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struct cpu_stopper *stopper2 = per_cpu_ptr(&cpu_stopper, cpu2);
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int err;
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retry:
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spin_lock_irq(&stopper1->lock);
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spin_lock_nested(&stopper2->lock, SINGLE_DEPTH_NESTING);
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raw_spin_lock_irq(&stopper1->lock);
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raw_spin_lock_nested(&stopper2->lock, SINGLE_DEPTH_NESTING);
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err = -ENOENT;
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if (!stopper1->enabled || !stopper2->enabled)
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@ -255,8 +255,8 @@ static int cpu_stop_queue_two_works(int cpu1, struct cpu_stop_work *work1,
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__cpu_stop_queue_work(stopper1, work1);
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__cpu_stop_queue_work(stopper2, work2);
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unlock:
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spin_unlock(&stopper2->lock);
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spin_unlock_irq(&stopper1->lock);
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raw_spin_unlock(&stopper2->lock);
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raw_spin_unlock_irq(&stopper1->lock);
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if (unlikely(err == -EDEADLK)) {
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while (stop_cpus_in_progress)
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@ -448,9 +448,9 @@ static int cpu_stop_should_run(unsigned int cpu)
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unsigned long flags;
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int run;
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spin_lock_irqsave(&stopper->lock, flags);
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raw_spin_lock_irqsave(&stopper->lock, flags);
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run = !list_empty(&stopper->works);
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spin_unlock_irqrestore(&stopper->lock, flags);
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raw_spin_unlock_irqrestore(&stopper->lock, flags);
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return run;
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}
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@ -461,13 +461,13 @@ static void cpu_stopper_thread(unsigned int cpu)
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repeat:
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work = NULL;
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spin_lock_irq(&stopper->lock);
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raw_spin_lock_irq(&stopper->lock);
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if (!list_empty(&stopper->works)) {
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work = list_first_entry(&stopper->works,
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struct cpu_stop_work, list);
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list_del_init(&work->list);
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}
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spin_unlock_irq(&stopper->lock);
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raw_spin_unlock_irq(&stopper->lock);
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if (work) {
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cpu_stop_fn_t fn = work->fn;
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@ -541,7 +541,7 @@ static int __init cpu_stop_init(void)
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for_each_possible_cpu(cpu) {
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struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
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spin_lock_init(&stopper->lock);
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raw_spin_lock_init(&stopper->lock);
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INIT_LIST_HEAD(&stopper->works);
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}
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