diff options
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 63 |
1 files changed, 40 insertions, 23 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 664ce5299334..82cf9dff4295 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -21,6 +21,7 @@ #include <linux/suspend.h> #include <linux/lockdep.h> #include <linux/tick.h> +#include <linux/irq.h> #include <trace/events/power.h> #include "smpboot.h" @@ -190,21 +191,22 @@ void cpu_hotplug_done(void) void cpu_hotplug_disable(void) { cpu_maps_update_begin(); - cpu_hotplug_disabled = 1; + cpu_hotplug_disabled++; cpu_maps_update_done(); } +EXPORT_SYMBOL_GPL(cpu_hotplug_disable); void cpu_hotplug_enable(void) { cpu_maps_update_begin(); - cpu_hotplug_disabled = 0; + WARN_ON(--cpu_hotplug_disabled < 0); cpu_maps_update_done(); } - +EXPORT_SYMBOL_GPL(cpu_hotplug_enable); #endif /* CONFIG_HOTPLUG_CPU */ /* Need to know about CPUs going up/down? */ -int __ref register_cpu_notifier(struct notifier_block *nb) +int register_cpu_notifier(struct notifier_block *nb) { int ret; cpu_maps_update_begin(); @@ -213,7 +215,7 @@ int __ref register_cpu_notifier(struct notifier_block *nb) return ret; } -int __ref __register_cpu_notifier(struct notifier_block *nb) +int __register_cpu_notifier(struct notifier_block *nb) { return raw_notifier_chain_register(&cpu_chain, nb); } @@ -243,7 +245,7 @@ static void cpu_notify_nofail(unsigned long val, void *v) EXPORT_SYMBOL(register_cpu_notifier); EXPORT_SYMBOL(__register_cpu_notifier); -void __ref unregister_cpu_notifier(struct notifier_block *nb) +void unregister_cpu_notifier(struct notifier_block *nb) { cpu_maps_update_begin(); raw_notifier_chain_unregister(&cpu_chain, nb); @@ -251,7 +253,7 @@ void __ref unregister_cpu_notifier(struct notifier_block *nb) } EXPORT_SYMBOL(unregister_cpu_notifier); -void __ref __unregister_cpu_notifier(struct notifier_block *nb) +void __unregister_cpu_notifier(struct notifier_block *nb) { raw_notifier_chain_unregister(&cpu_chain, nb); } @@ -328,7 +330,7 @@ struct take_cpu_down_param { }; /* Take this CPU down. */ -static int __ref take_cpu_down(void *_param) +static int take_cpu_down(void *_param) { struct take_cpu_down_param *param = _param; int err; @@ -347,7 +349,7 @@ static int __ref take_cpu_down(void *_param) } /* Requires cpu_add_remove_lock to be held */ -static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) +static int _cpu_down(unsigned int cpu, int tasks_frozen) { int err, nr_calls = 0; void *hcpu = (void *)(long)cpu; @@ -380,25 +382,31 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) * will observe it. * * For CONFIG_PREEMPT we have preemptible RCU and its sync_rcu() might - * not imply sync_sched(), so explicitly call both. + * not imply sync_sched(), so wait for both. * * Do sync before park smpboot threads to take care the rcu boost case. */ -#ifdef CONFIG_PREEMPT - synchronize_sched(); -#endif - synchronize_rcu(); + if (IS_ENABLED(CONFIG_PREEMPT)) + synchronize_rcu_mult(call_rcu, call_rcu_sched); + else + synchronize_rcu(); smpboot_park_threads(cpu); /* - * So now all preempt/rcu users must observe !cpu_active(). + * Prevent irq alloc/free while the dying cpu reorganizes the + * interrupt affinities. */ + irq_lock_sparse(); + /* + * So now all preempt/rcu users must observe !cpu_active(). + */ err = stop_machine(take_cpu_down, &tcd_param, cpumask_of(cpu)); if (err) { /* CPU didn't die: tell everyone. Can't complain. */ cpu_notify_nofail(CPU_DOWN_FAILED | mod, hcpu); + irq_unlock_sparse(); goto out_release; } BUG_ON(cpu_online(cpu)); @@ -415,6 +423,9 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen) smp_mb(); /* Read from cpu_dead_idle before __cpu_die(). */ per_cpu(cpu_dead_idle, cpu) = false; + /* Interrupts are moved away from the dying cpu, reenable alloc/free */ + irq_unlock_sparse(); + hotplug_cpu__broadcast_tick_pull(cpu); /* This actually kills the CPU. */ __cpu_die(cpu); @@ -432,7 +443,7 @@ out_release: return err; } -int __ref cpu_down(unsigned int cpu) +int cpu_down(unsigned int cpu) { int err; @@ -519,6 +530,7 @@ static int _cpu_up(unsigned int cpu, int tasks_frozen) /* Arch-specific enabling code. */ ret = __cpu_up(cpu, idle); + if (ret != 0) goto out_notify; BUG_ON(!cpu_online(cpu)); @@ -597,13 +609,18 @@ int disable_nonboot_cpus(void) } } - if (!error) { + if (!error) BUG_ON(num_online_cpus() > 1); - /* Make sure the CPUs won't be enabled by someone else */ - cpu_hotplug_disabled = 1; - } else { + else pr_err("Non-boot CPUs are not disabled\n"); - } + + /* + * Make sure the CPUs won't be enabled by someone else. We need to do + * this even in case of failure as all disable_nonboot_cpus() users are + * supposed to do enable_nonboot_cpus() on the failure path. + */ + cpu_hotplug_disabled++; + cpu_maps_update_done(); return error; } @@ -616,13 +633,13 @@ void __weak arch_enable_nonboot_cpus_end(void) { } -void __ref enable_nonboot_cpus(void) +void enable_nonboot_cpus(void) { int cpu, error; /* Allow everyone to use the CPU hotplug again */ cpu_maps_update_begin(); - cpu_hotplug_disabled = 0; + WARN_ON(--cpu_hotplug_disabled < 0); if (cpumask_empty(frozen_cpus)) goto out; |