diff options
Diffstat (limited to 'kernel/stop_machine.c')
| -rw-r--r-- | kernel/stop_machine.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/kernel/stop_machine.c b/kernel/stop_machine.c index b4f83f7bdf86..998d50ee2d9b 100644 --- a/kernel/stop_machine.c +++ b/kernel/stop_machine.c @@ -7,6 +7,7 @@ * Copyright (C) 2010 SUSE Linux Products GmbH * Copyright (C) 2010 Tejun Heo <tj@kernel.org> */ +#include <linux/compiler.h> #include <linux/completion.h> #include <linux/cpu.h> #include <linux/init.h> @@ -167,7 +168,7 @@ static void set_state(struct multi_stop_data *msdata, /* Reset ack counter. */ atomic_set(&msdata->thread_ack, msdata->num_threads); smp_wmb(); - msdata->state = newstate; + WRITE_ONCE(msdata->state, newstate); } /* Last one to ack a state moves to the next state. */ @@ -186,7 +187,7 @@ void __weak stop_machine_yield(const struct cpumask *cpumask) static int multi_cpu_stop(void *data) { struct multi_stop_data *msdata = data; - enum multi_stop_state curstate = MULTI_STOP_NONE; + enum multi_stop_state newstate, curstate = MULTI_STOP_NONE; int cpu = smp_processor_id(), err = 0; const struct cpumask *cpumask; unsigned long flags; @@ -210,8 +211,9 @@ static int multi_cpu_stop(void *data) do { /* Chill out and ensure we re-read multi_stop_state. */ stop_machine_yield(cpumask); - if (msdata->state != curstate) { - curstate = msdata->state; + newstate = READ_ONCE(msdata->state); + if (newstate != curstate) { + curstate = newstate; switch (curstate) { case MULTI_STOP_DISABLE_IRQ: local_irq_disable(); @@ -383,6 +385,7 @@ static bool queue_stop_cpus_work(const struct cpumask *cpumask, */ preempt_disable(); stop_cpus_in_progress = true; + barrier(); for_each_cpu(cpu, cpumask) { work = &per_cpu(cpu_stopper.stop_work, cpu); work->fn = fn; @@ -391,6 +394,7 @@ static bool queue_stop_cpus_work(const struct cpumask *cpumask, if (cpu_stop_queue_work(cpu, work)) queued = true; } + barrier(); stop_cpus_in_progress = false; preempt_enable(); |
