diff options
Diffstat (limited to 'kernel/cpu.c')
| -rw-r--r-- | kernel/cpu.c | 235 |
1 files changed, 51 insertions, 184 deletions
diff --git a/kernel/cpu.c b/kernel/cpu.c index 5339aca811d2..042fd7e8e030 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -183,23 +183,16 @@ EXPORT_SYMBOL_GPL(cpuhp_tasks_frozen); /* * The following two APIs (cpu_maps_update_begin/done) must be used when * attempting to serialize the updates to cpu_online_mask & cpu_present_mask. - * The APIs cpu_notifier_register_begin/done() must be used to protect CPU - * hotplug callback (un)registration performed using __register_cpu_notifier() - * or __unregister_cpu_notifier(). */ void cpu_maps_update_begin(void) { mutex_lock(&cpu_add_remove_lock); } -EXPORT_SYMBOL(cpu_notifier_register_begin); void cpu_maps_update_done(void) { mutex_unlock(&cpu_add_remove_lock); } -EXPORT_SYMBOL(cpu_notifier_register_done); - -static RAW_NOTIFIER_HEAD(cpu_chain); /* If set, cpu_up and cpu_down will return -EBUSY and do nothing. * Should always be manipulated under cpu_add_remove_lock @@ -349,66 +342,7 @@ void cpu_hotplug_enable(void) EXPORT_SYMBOL_GPL(cpu_hotplug_enable); #endif /* CONFIG_HOTPLUG_CPU */ -/* Need to know about CPUs going up/down? */ -int register_cpu_notifier(struct notifier_block *nb) -{ - int ret; - cpu_maps_update_begin(); - ret = raw_notifier_chain_register(&cpu_chain, nb); - cpu_maps_update_done(); - return ret; -} - -int __register_cpu_notifier(struct notifier_block *nb) -{ - return raw_notifier_chain_register(&cpu_chain, nb); -} - -static int __cpu_notify(unsigned long val, unsigned int cpu, int nr_to_call, - int *nr_calls) -{ - unsigned long mod = cpuhp_tasks_frozen ? CPU_TASKS_FROZEN : 0; - void *hcpu = (void *)(long)cpu; - - int ret; - - ret = __raw_notifier_call_chain(&cpu_chain, val | mod, hcpu, nr_to_call, - nr_calls); - - return notifier_to_errno(ret); -} - -static int cpu_notify(unsigned long val, unsigned int cpu) -{ - return __cpu_notify(val, cpu, -1, NULL); -} - -static void cpu_notify_nofail(unsigned long val, unsigned int cpu) -{ - BUG_ON(cpu_notify(val, cpu)); -} - /* Notifier wrappers for transitioning to state machine */ -static int notify_prepare(unsigned int cpu) -{ - int nr_calls = 0; - int ret; - - ret = __cpu_notify(CPU_UP_PREPARE, cpu, -1, &nr_calls); - if (ret) { - nr_calls--; - printk(KERN_WARNING "%s: attempt to bring up CPU %u failed\n", - __func__, cpu); - __cpu_notify(CPU_UP_CANCELED, cpu, nr_calls, NULL); - } - return ret; -} - -static int notify_online(unsigned int cpu) -{ - cpu_notify(CPU_ONLINE, cpu); - return 0; -} static int bringup_wait_for_ap(unsigned int cpu) { @@ -433,10 +367,8 @@ static int bringup_cpu(unsigned int cpu) /* Arch-specific enabling code. */ ret = __cpu_up(cpu, idle); irq_unlock_sparse(); - if (ret) { - cpu_notify(CPU_UP_CANCELED, cpu); + if (ret) return ret; - } ret = bringup_wait_for_ap(cpu); BUG_ON(!cpu_online(cpu)); return ret; @@ -565,11 +497,6 @@ static void cpuhp_thread_fun(unsigned int cpu) BUG_ON(st->state < CPUHP_AP_ONLINE_IDLE); undo_cpu_down(cpu, st); - /* - * This is a momentary workaround to keep the notifier users - * happy. Will go away once we got rid of the notifiers. - */ - cpu_notify_nofail(CPU_DOWN_FAILED, cpu); st->rollback = false; } else { /* Cannot happen .... */ @@ -659,22 +586,6 @@ void __init cpuhp_threads_init(void) kthread_unpark(this_cpu_read(cpuhp_state.thread)); } -EXPORT_SYMBOL(register_cpu_notifier); -EXPORT_SYMBOL(__register_cpu_notifier); -void unregister_cpu_notifier(struct notifier_block *nb) -{ - cpu_maps_update_begin(); - raw_notifier_chain_unregister(&cpu_chain, nb); - cpu_maps_update_done(); -} -EXPORT_SYMBOL(unregister_cpu_notifier); - -void __unregister_cpu_notifier(struct notifier_block *nb) -{ - raw_notifier_chain_unregister(&cpu_chain, nb); -} -EXPORT_SYMBOL(__unregister_cpu_notifier); - #ifdef CONFIG_HOTPLUG_CPU /** * clear_tasks_mm_cpumask - Safely clear tasks' mm_cpumask for a CPU @@ -741,20 +652,6 @@ static inline void check_for_tasks(int dead_cpu) read_unlock(&tasklist_lock); } -static int notify_down_prepare(unsigned int cpu) -{ - int err, nr_calls = 0; - - err = __cpu_notify(CPU_DOWN_PREPARE, cpu, -1, &nr_calls); - if (err) { - nr_calls--; - __cpu_notify(CPU_DOWN_FAILED, cpu, nr_calls, NULL); - pr_warn("%s: attempt to take down CPU %u failed\n", - __func__, cpu); - } - return err; -} - /* Take this CPU down. */ static int take_cpu_down(void *_param) { @@ -833,13 +730,6 @@ static int takedown_cpu(unsigned int cpu) return 0; } -static int notify_dead(unsigned int cpu) -{ - cpu_notify_nofail(CPU_DEAD, cpu); - check_for_tasks(cpu); - return 0; -} - static void cpuhp_complete_idle_dead(void *arg) { struct cpuhp_cpu_state *st = arg; @@ -863,9 +753,7 @@ void cpuhp_report_idle_dead(void) } #else -#define notify_down_prepare NULL #define takedown_cpu NULL -#define notify_dead NULL #endif #ifdef CONFIG_HOTPLUG_CPU @@ -924,9 +812,6 @@ static int __ref _cpu_down(unsigned int cpu, int tasks_frozen, hasdied = prev_state != st->state && st->state == CPUHP_OFFLINE; out: cpu_hotplug_done(); - /* This post dead nonsense must die */ - if (!ret && hasdied) - cpu_notify_nofail(CPU_POST_DEAD, cpu); return ret; } @@ -1292,17 +1177,6 @@ static struct cpuhp_step cpuhp_bp_states[] = { .teardown.single = rcutree_dead_cpu, }, /* - * Preparatory and dead notifiers. Will be replaced once the notifiers - * are converted to states. - */ - [CPUHP_NOTIFY_PREPARE] = { - .name = "notify:prepare", - .startup.single = notify_prepare, - .teardown.single = notify_dead, - .skip_onerr = true, - .cant_stop = true, - }, - /* * On the tear-down path, timers_dead_cpu() must be invoked * before blk_mq_queue_reinit_notify() from notify_dead(), * otherwise a RCU stall occurs. @@ -1391,17 +1265,6 @@ static struct cpuhp_step cpuhp_ap_states[] = { .startup.single = rcutree_online_cpu, .teardown.single = rcutree_offline_cpu, }, - - /* - * Online/down_prepare notifiers. Will be removed once the notifiers - * are converted to states. - */ - [CPUHP_AP_NOTIFY_ONLINE] = { - .name = "notify:online", - .startup.single = notify_online, - .teardown.single = notify_down_prepare, - .skip_onerr = true, - }, #endif /* * The dynamically registered state space is here @@ -1432,23 +1295,53 @@ static int cpuhp_cb_check(enum cpuhp_state state) return 0; } -static void cpuhp_store_callbacks(enum cpuhp_state state, - const char *name, - int (*startup)(unsigned int cpu), - int (*teardown)(unsigned int cpu), - bool multi_instance) +/* + * Returns a free for dynamic slot assignment of the Online state. The states + * are protected by the cpuhp_slot_states mutex and an empty slot is identified + * by having no name assigned. + */ +static int cpuhp_reserve_state(enum cpuhp_state state) +{ + enum cpuhp_state i; + + for (i = CPUHP_AP_ONLINE_DYN; i <= CPUHP_AP_ONLINE_DYN_END; i++) { + if (!cpuhp_ap_states[i].name) + return i; + } + WARN(1, "No more dynamic states available for CPU hotplug\n"); + return -ENOSPC; +} + +static int cpuhp_store_callbacks(enum cpuhp_state state, const char *name, + int (*startup)(unsigned int cpu), + int (*teardown)(unsigned int cpu), + bool multi_instance) { /* (Un)Install the callbacks for further cpu hotplug operations */ struct cpuhp_step *sp; + int ret = 0; mutex_lock(&cpuhp_state_mutex); + + if (state == CPUHP_AP_ONLINE_DYN) { + ret = cpuhp_reserve_state(state); + if (ret < 0) + goto out; + state = ret; + } sp = cpuhp_get_step(state); + if (name && sp->name) { + ret = -EBUSY; + goto out; + } sp->startup.single = startup; sp->teardown.single = teardown; sp->name = name; sp->multi_instance = multi_instance; INIT_HLIST_HEAD(&sp->list); +out: mutex_unlock(&cpuhp_state_mutex); + return ret; } static void *cpuhp_get_teardown_cb(enum cpuhp_state state) @@ -1509,29 +1402,6 @@ static void cpuhp_rollback_install(int failedcpu, enum cpuhp_state state, } } -/* - * Returns a free for dynamic slot assignment of the Online state. The states - * are protected by the cpuhp_slot_states mutex and an empty slot is identified - * by having no name assigned. - */ -static int cpuhp_reserve_state(enum cpuhp_state state) -{ - enum cpuhp_state i; - - mutex_lock(&cpuhp_state_mutex); - for (i = CPUHP_AP_ONLINE_DYN; i <= CPUHP_AP_ONLINE_DYN_END; i++) { - if (cpuhp_ap_states[i].name) - continue; - - cpuhp_ap_states[i].name = "Reserved"; - mutex_unlock(&cpuhp_state_mutex); - return i; - } - mutex_unlock(&cpuhp_state_mutex); - WARN(1, "No more dynamic states available for CPU hotplug\n"); - return -ENOSPC; -} - int __cpuhp_state_add_instance(enum cpuhp_state state, struct hlist_node *node, bool invoke) { @@ -1580,11 +1450,13 @@ EXPORT_SYMBOL_GPL(__cpuhp_state_add_instance); /** * __cpuhp_setup_state - Setup the callbacks for an hotplug machine state - * @state: The state to setup - * @invoke: If true, the startup function is invoked for cpus where - * cpu state >= @state - * @startup: startup callback function - * @teardown: teardown callback function + * @state: The state to setup + * @invoke: If true, the startup function is invoked for cpus where + * cpu state >= @state + * @startup: startup callback function + * @teardown: teardown callback function + * @multi_instance: State is set up for multiple instances which get + * added afterwards. * * Returns: * On success: @@ -1599,25 +1471,16 @@ int __cpuhp_setup_state(enum cpuhp_state state, bool multi_instance) { int cpu, ret = 0; - int dyn_state = 0; if (cpuhp_cb_check(state) || !name) return -EINVAL; get_online_cpus(); - /* currently assignments for the ONLINE state are possible */ - if (state == CPUHP_AP_ONLINE_DYN) { - dyn_state = 1; - ret = cpuhp_reserve_state(state); - if (ret < 0) - goto out; - state = ret; - } + ret = cpuhp_store_callbacks(state, name, startup, teardown, + multi_instance); - cpuhp_store_callbacks(state, name, startup, teardown, multi_instance); - - if (!invoke || !startup) + if (ret || !invoke || !startup) goto out; /* @@ -1641,7 +1504,11 @@ int __cpuhp_setup_state(enum cpuhp_state state, } out: put_online_cpus(); - if (!ret && dyn_state) + /* + * If the requested state is CPUHP_AP_ONLINE_DYN, return the + * dynamically allocated state in case of success. + */ + if (!ret && state == CPUHP_AP_ONLINE_DYN) return state; return ret; } |