diff options
| -rw-r--r-- | include/linux/cpumask.h | 12 | ||||
| -rw-r--r-- | kernel/smp.c | 29 |
2 files changed, 20 insertions, 21 deletions
diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h index 796df12091b7..9b1d458aac6e 100644 --- a/include/linux/cpumask.h +++ b/include/linux/cpumask.h @@ -715,6 +715,18 @@ static inline int cpumask_test_and_set_cpu(int cpu, struct cpumask *cpumask) } /** + * cpumask_test_and_clear_cpu - atomically test and clear a cpu in a cpumask + * @cpu: cpu number (< nr_cpu_ids) + * @cpumask: the cpumask pointer + * + * test_and_clear_bit wrapper for cpumasks. + */ +static inline int cpumask_test_and_clear_cpu(int cpu, struct cpumask *cpumask) +{ + return test_and_clear_bit(cpumask_check(cpu), cpumask_bits(cpumask)); +} + +/** * cpumask_setall - set all cpus (< nr_cpu_ids) in a cpumask * @dstp: the cpumask pointer */ diff --git a/kernel/smp.c b/kernel/smp.c index 8e218500ab14..fd47a256a24e 100644 --- a/kernel/smp.c +++ b/kernel/smp.c @@ -29,8 +29,7 @@ enum { struct call_function_data { struct call_single_data csd; - spinlock_t lock; - unsigned int refs; + atomic_t refs; cpumask_var_t cpumask; }; @@ -39,9 +38,7 @@ struct call_single_queue { spinlock_t lock; }; -static DEFINE_PER_CPU(struct call_function_data, cfd_data) = { - .lock = __SPIN_LOCK_UNLOCKED(cfd_data.lock), -}; +static DEFINE_PER_CPU(struct call_function_data, cfd_data); static int hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu) @@ -196,25 +193,18 @@ void generic_smp_call_function_interrupt(void) list_for_each_entry_rcu(data, &call_function.queue, csd.list) { int refs; - spin_lock(&data->lock); - if (!cpumask_test_cpu(cpu, data->cpumask)) { - spin_unlock(&data->lock); + if (!cpumask_test_and_clear_cpu(cpu, data->cpumask)) continue; - } - cpumask_clear_cpu(cpu, data->cpumask); - spin_unlock(&data->lock); data->csd.func(data->csd.info); - spin_lock(&data->lock); - WARN_ON(data->refs == 0); - refs = --data->refs; + refs = atomic_dec_return(&data->refs); + WARN_ON(refs < 0); if (!refs) { spin_lock(&call_function.lock); list_del_rcu(&data->csd.list); spin_unlock(&call_function.lock); } - spin_unlock(&data->lock); if (refs) continue; @@ -419,23 +409,20 @@ void smp_call_function_many(const struct cpumask *mask, data = &__get_cpu_var(cfd_data); csd_lock(&data->csd); - spin_lock_irqsave(&data->lock, flags); data->csd.func = func; data->csd.info = info; cpumask_and(data->cpumask, mask, cpu_online_mask); cpumask_clear_cpu(this_cpu, data->cpumask); - data->refs = cpumask_weight(data->cpumask); + atomic_set(&data->refs, cpumask_weight(data->cpumask)); - spin_lock(&call_function.lock); + spin_lock_irqsave(&call_function.lock, flags); /* * Place entry at the _HEAD_ of the list, so that any cpu still * observing the entry in generic_smp_call_function_interrupt() * will not miss any other list entries: */ list_add_rcu(&data->csd.list, &call_function.queue); - spin_unlock(&call_function.lock); - - spin_unlock_irqrestore(&data->lock, flags); + spin_unlock_irqrestore(&call_function.lock, flags); /* * Make the list addition visible before sending the ipi. |