/*
* 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
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)
{
/* 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;
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 .... */
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
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)
{
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;
}
#else
-#define notify_down_prepare NULL
#define takedown_cpu NULL
-#define notify_dead NULL
#endif
#ifdef CONFIG_HOTPLUG_CPU
{
struct cpuhp_cpu_state *st = per_cpu_ptr(&cpuhp_state, cpu);
int prev_state, ret = 0;
- bool hasdied = false;
if (num_online_cpus() == 1)
return -EBUSY;
cpuhp_kick_ap_work(cpu);
}
- 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;
}
.startup.single = rcutree_prepare_cpu,
.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(),
.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
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, end;
+ struct cpuhp_step *step;
+
+ switch (state) {
+ case CPUHP_AP_ONLINE_DYN:
+ step = cpuhp_ap_states + CPUHP_AP_ONLINE_DYN;
+ end = CPUHP_AP_ONLINE_DYN_END;
+ break;
+ case CPUHP_BP_PREPARE_DYN:
+ step = cpuhp_bp_states + CPUHP_BP_PREPARE_DYN;
+ end = CPUHP_BP_PREPARE_DYN_END;
+ break;
+ default:
+ return -EINVAL;
+ }
+
+ for (i = state; i <= end; i++, step++) {
+ if (!step->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 || state == CPUHP_BP_PREPARE_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)
}
}
-/*
- * 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)
{
/**
* __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:
bool multi_instance)
{
int cpu, ret = 0;
- int dyn_state = 0;
+ bool dynstate;
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;
+ ret = cpuhp_store_callbacks(state, name, startup, teardown,
+ multi_instance);
+
+ dynstate = state == CPUHP_AP_ONLINE_DYN;
+ if (ret > 0 && dynstate) {
state = ret;
+ ret = 0;
}
- cpuhp_store_callbacks(state, name, startup, teardown, multi_instance);
-
- if (!invoke || !startup)
+ if (ret || !invoke || !startup)
goto out;
/*
}
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 && dynstate)
return state;
return ret;
}
projects / karo-tx-linux.git / blobdiff