diff options
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 73 |
1 files changed, 65 insertions, 8 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 1979b8927b86..be9335da82f1 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -48,12 +48,14 @@ static DEFINE_PER_CPU(struct cpuhp_cpu_state, cpuhp_state); * @teardown: Teardown function of the step * @skip_onerr: Do not invoke the functions on error rollback * Will go away once the notifiers are gone + * @cant_stop: Bringup/teardown can't be stopped at this step */ struct cpuhp_step { const char *name; int (*startup)(unsigned int cpu); int (*teardown)(unsigned int cpu); bool skip_onerr; + bool cant_stop; }; static DEFINE_MUTEX(cpuhp_state_mutex); @@ -558,7 +560,7 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, if (num_online_cpus() == 1) return -EBUSY; - if (!cpu_online(cpu)) + if (!cpu_present(cpu)) return -EINVAL; cpu_hotplug_begin(); @@ -683,16 +685,25 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen, enum cpuhp_state target) cpu_hotplug_begin(); - if (cpu_online(cpu) || !cpu_present(cpu)) { + if (!cpu_present(cpu)) { ret = -EINVAL; goto out; } - /* Let it fail before we try to bring the cpu up */ - idle = idle_thread_get(cpu); - if (IS_ERR(idle)) { - ret = PTR_ERR(idle); + /* + * The caller of do_cpu_up might have raced with another + * caller. Ignore it for now. + */ + if (st->state >= target) goto out; + + if (st->state == CPUHP_OFFLINE) { + /* Let it fail before we try to bring the cpu up */ + idle = idle_thread_get(cpu); + if (IS_ERR(idle)) { + ret = PTR_ERR(idle); + goto out; + } } cpuhp_tasks_frozen = tasks_frozen; @@ -909,27 +920,32 @@ static struct cpuhp_step cpuhp_bp_states[] = { .name = "threads:create", .startup = smpboot_create_threads, .teardown = NULL, + .cant_stop = true, }, [CPUHP_NOTIFY_PREPARE] = { .name = "notify:prepare", .startup = notify_prepare, .teardown = notify_dead, .skip_onerr = true, + .cant_stop = true, }, [CPUHP_BRINGUP_CPU] = { .name = "cpu:bringup", .startup = bringup_cpu, .teardown = NULL, + .cant_stop = true, }, [CPUHP_TEARDOWN_CPU] = { .name = "cpu:teardown", .startup = NULL, .teardown = takedown_cpu, + .cant_stop = true, }, [CPUHP_NOTIFY_ONLINE] = { .name = "notify:online", .startup = notify_online, .teardown = notify_down_prepare, + .cant_stop = true, }, #endif [CPUHP_ONLINE] = { @@ -947,6 +963,7 @@ static struct cpuhp_step cpuhp_ap_states[] = { .startup = notify_starting, .teardown = notify_dying, .skip_onerr = true, + .cant_stop = true, }, #endif [CPUHP_ONLINE] = { @@ -979,6 +996,46 @@ static ssize_t show_cpuhp_state(struct device *dev, } static DEVICE_ATTR(state, 0444, show_cpuhp_state, NULL); +static ssize_t write_cpuhp_target(struct device *dev, + struct device_attribute *attr, + const char *buf, size_t count) +{ + struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, dev->id); + struct cpuhp_step *sp; + int target, ret; + + ret = kstrtoint(buf, 10, &target); + if (ret) + return ret; + +#ifdef CONFIG_CPU_HOTPLUG_STATE_CONTROL + if (target < CPUHP_OFFLINE || target > CPUHP_ONLINE) + return -EINVAL; +#else + if (target != CPUHP_OFFLINE && target != CPUHP_ONLINE) + return -EINVAL; +#endif + + ret = lock_device_hotplug_sysfs(); + if (ret) + return ret; + + mutex_lock(&cpuhp_state_mutex); + sp = cpuhp_get_step(target); + ret = !sp->name || sp->cant_stop ? -EINVAL : 0; + mutex_unlock(&cpuhp_state_mutex); + if (ret) + return ret; + + if (st->state < target) + ret = do_cpu_up(dev->id, target); + else + ret = do_cpu_down(dev->id, target); + + unlock_device_hotplug(); + return ret ? ret : count; +} + static ssize_t show_cpuhp_target(struct device *dev, struct device_attribute *attr, char *buf) { @@ -986,7 +1043,7 @@ static ssize_t show_cpuhp_target(struct device *dev, return sprintf(buf, "%d\n", st->target); } -static DEVICE_ATTR(target, 0444, show_cpuhp_target, NULL); +static DEVICE_ATTR(target, 0644, show_cpuhp_target, write_cpuhp_target); static struct attribute *cpuhp_cpu_attrs[] = { &dev_attr_state.attr, @@ -1007,7 +1064,7 @@ static ssize_t show_cpuhp_states(struct device *dev, int i; mutex_lock(&cpuhp_state_mutex); - for (i = 0; i <= CPUHP_ONLINE; i++) { + for (i = CPUHP_OFFLINE; i <= CPUHP_ONLINE; i++) { struct cpuhp_step *sp = cpuhp_get_step(i); if (sp->name) { |