4.9-stable review patch. If anyone has any objections, please let me know.
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From: Thomas Gleixner tglx@linutronix.de
[ Upstream commit de5b55c1d4e30740009864eb35ce4ed856aac01d ]
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 Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- kernel/stop_machine.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-)
--- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -36,7 +36,7 @@ struct cpu_stop_done { struct cpu_stopper { struct task_struct *thread;
- spinlock_t lock; + raw_spinlock_t lock; bool enabled; /* is this stopper enabled? */ struct list_head works; /* list of pending works */
@@ -78,13 +78,13 @@ static bool cpu_stop_queue_work(unsigned unsigned long flags; bool enabled;
- spin_lock_irqsave(&stopper->lock, flags); + raw_spin_lock_irqsave(&stopper->lock, flags); enabled = stopper->enabled; if (enabled) __cpu_stop_queue_work(stopper, work); else if (work->done) cpu_stop_signal_done(work->done); - spin_unlock_irqrestore(&stopper->lock, flags); + raw_spin_unlock_irqrestore(&stopper->lock, flags);
return enabled; } @@ -231,8 +231,8 @@ static int cpu_stop_queue_two_works(int struct cpu_stopper *stopper2 = per_cpu_ptr(&cpu_stopper, cpu2); int err; retry: - spin_lock_irq(&stopper1->lock); - spin_lock_nested(&stopper2->lock, SINGLE_DEPTH_NESTING); + raw_spin_lock_irq(&stopper1->lock); + raw_spin_lock_nested(&stopper2->lock, SINGLE_DEPTH_NESTING);
err = -ENOENT; if (!stopper1->enabled || !stopper2->enabled) @@ -255,8 +255,8 @@ retry: __cpu_stop_queue_work(stopper1, work1); __cpu_stop_queue_work(stopper2, work2); unlock: - spin_unlock(&stopper2->lock); - spin_unlock_irq(&stopper1->lock); + raw_spin_unlock(&stopper2->lock); + raw_spin_unlock_irq(&stopper1->lock);
if (unlikely(err == -EDEADLK)) { while (stop_cpus_in_progress) @@ -448,9 +448,9 @@ static int cpu_stop_should_run(unsigned unsigned long flags; int run;
- spin_lock_irqsave(&stopper->lock, flags); + raw_spin_lock_irqsave(&stopper->lock, flags); run = !list_empty(&stopper->works); - spin_unlock_irqrestore(&stopper->lock, flags); + raw_spin_unlock_irqrestore(&stopper->lock, flags); return run; }
@@ -461,13 +461,13 @@ static void cpu_stopper_thread(unsigned
repeat: work = NULL; - spin_lock_irq(&stopper->lock); + raw_spin_lock_irq(&stopper->lock); if (!list_empty(&stopper->works)) { work = list_first_entry(&stopper->works, struct cpu_stop_work, list); list_del_init(&work->list); } - spin_unlock_irq(&stopper->lock); + raw_spin_unlock_irq(&stopper->lock);
if (work) { cpu_stop_fn_t fn = work->fn; @@ -541,7 +541,7 @@ static int __init cpu_stop_init(void) for_each_possible_cpu(cpu) { struct cpu_stopper *stopper = &per_cpu(cpu_stopper, cpu);
- spin_lock_init(&stopper->lock); + raw_spin_lock_init(&stopper->lock); INIT_LIST_HEAD(&stopper->works); }