1 files changed, 290 insertions, 301 deletions

diff --git a/kernel/smp.c b/kernel/smp.c
index db197d60489..80c33f8de14 100644
--- a/kernel/smp.c
+++ b/kernel/smp.c
@@ -13,34 +13,23 @@
 #include <linux/smp.h>
 #include <linux/cpu.h>
 
-#ifdef CONFIG_USE_GENERIC_SMP_HELPERS
-static struct {
-	struct list_head	queue;
-	raw_spinlock_t		lock;
-} call_function __cacheline_aligned_in_smp =
-	{
-		.queue		= LIST_HEAD_INIT(call_function.queue),
-		.lock		= __RAW_SPIN_LOCK_UNLOCKED(call_function.lock),
-	};
+#include "smpboot.h"
 
 enum {
 	CSD_FLAG_LOCK		= 0x01,
+	CSD_FLAG_WAIT		= 0x02,
 };
 
 struct call_function_data {
-	struct call_single_data	csd;
-	atomic_t		refs;
+	struct call_single_data	__percpu *csd;
 	cpumask_var_t		cpumask;
 };
 
 static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_function_data, cfd_data);
 
-struct call_single_queue {
-	struct list_head	list;
-	raw_spinlock_t		lock;
-};
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct llist_head, call_single_queue);
 
-static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_queue, call_single_queue);
+static void flush_smp_call_function_queue(bool warn_cpu_offline);
 
 static int
 hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
@@ -54,15 +43,36 @@ hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
 		if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL,
 				cpu_to_node(cpu)))
 			return notifier_from_errno(-ENOMEM);
+		cfd->csd = alloc_percpu(struct call_single_data);
+		if (!cfd->csd) {
+			free_cpumask_var(cfd->cpumask);
+			return notifier_from_errno(-ENOMEM);
+		}
 		break;
 
 #ifdef CONFIG_HOTPLUG_CPU
 	case CPU_UP_CANCELED:
 	case CPU_UP_CANCELED_FROZEN:
+		/* Fall-through to the CPU_DEAD[_FROZEN] case. */
 
 	case CPU_DEAD:
 	case CPU_DEAD_FROZEN:
 		free_cpumask_var(cfd->cpumask);
+		free_percpu(cfd->csd);
+		break;
+
+	case CPU_DYING:
+	case CPU_DYING_FROZEN:
+		/*
+		 * The IPIs for the smp-call-function callbacks queued by other
+		 * CPUs might arrive late, either due to hardware latencies or
+		 * because this CPU disabled interrupts (inside stop-machine)
+		 * before the IPIs were sent. So flush out any pending callbacks
+		 * explicitly (without waiting for the IPIs to arrive), to
+		 * ensure that the outgoing CPU doesn't go offline with work
+		 * still pending.
+		 */
+		flush_smp_call_function_queue(false);
 		break;
 #endif
 	};
@@ -70,7 +80,7 @@ hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
 	return NOTIFY_OK;
 }
 
-static struct notifier_block __cpuinitdata hotplug_cfd_notifier = {
+static struct notifier_block hotplug_cfd_notifier = {
 	.notifier_call		= hotplug_cfd,
 };
 
@@ -79,12 +89,8 @@ void __init call_function_init(void)
 	void *cpu = (void *)(long)smp_processor_id();
 	int i;
 
-	for_each_possible_cpu(i) {
-		struct call_single_queue *q = &per_cpu(call_single_queue, i);
-
-		raw_spin_lock_init(&q->lock);
-		INIT_LIST_HEAD(&q->list);
-	}
+	for_each_possible_cpu(i)
+		init_llist_head(&per_cpu(call_single_queue, i));
 
 	hotplug_cfd(&hotplug_cfd_notifier, CPU_UP_PREPARE, cpu);
 	register_cpu_notifier(&hotplug_cfd_notifier);
@@ -97,16 +103,16 @@ void __init call_function_init(void)
  * previous function call. For multi-cpu calls its even more interesting
  * as we'll have to ensure no other cpu is observing our csd.
  */
-static void csd_lock_wait(struct call_single_data *data)
+static void csd_lock_wait(struct call_single_data *csd)
 {
-	while (data->flags & CSD_FLAG_LOCK)
+	while (csd->flags & CSD_FLAG_LOCK)
 		cpu_relax();
 }
 
-static void csd_lock(struct call_single_data *data)
+static void csd_lock(struct call_single_data *csd)
 {
-	csd_lock_wait(data);
-	data->flags = CSD_FLAG_LOCK;
+	csd_lock_wait(csd);
+	csd->flags |= CSD_FLAG_LOCK;
 
 	/*
 	 * prevent CPU from reordering the above assignment
@@ -116,34 +122,57 @@ static void csd_lock(struct call_single_data *data)
 	smp_mb();
 }
 
-static void csd_unlock(struct call_single_data *data)
+static void csd_unlock(struct call_single_data *csd)
 {
-	WARN_ON(!(data->flags & CSD_FLAG_LOCK));
+	WARN_ON((csd->flags & CSD_FLAG_WAIT) && !(csd->flags & CSD_FLAG_LOCK));
 
 	/*
 	 * ensure we're all done before releasing data:
 	 */
 	smp_mb();
 
-	data->flags &= ~CSD_FLAG_LOCK;
+	csd->flags &= ~CSD_FLAG_LOCK;
 }
 
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);
+
 /*
  * Insert a previously allocated call_single_data element
  * for execution on the given CPU. data must already have
  * ->func, ->info, and ->flags set.
  */
-static
-void generic_exec_single(int cpu, struct call_single_data *data, int wait)
+static int generic_exec_single(int cpu, struct call_single_data *csd,
+			       smp_call_func_t func, void *info, int wait)
 {
-	struct call_single_queue *dst = &per_cpu(call_single_queue, cpu);
+	struct call_single_data csd_stack = { .flags = 0 };
 	unsigned long flags;
-	int ipi;
 
-	raw_spin_lock_irqsave(&dst->lock, flags);
-	ipi = list_empty(&dst->list);
-	list_add_tail(&data->list, &dst->list);
-	raw_spin_unlock_irqrestore(&dst->lock, flags);
+
+	if (cpu == smp_processor_id()) {
+		local_irq_save(flags);
+		func(info);
+		local_irq_restore(flags);
+		return 0;
+	}
+
+
+	if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu))
+		return -ENXIO;
+
+
+	if (!csd) {
+		csd = &csd_stack;
+		if (!wait)
+			csd = &__get_cpu_var(csd_data);
+	}
+
+	csd_lock(csd);
+
+	csd->func = func;
+	csd->info = info;
+
+	if (wait)
+		csd->flags |= CSD_FLAG_WAIT;
 
 	/*
 	 * The list addition should be visible before sending the IPI
@@ -156,136 +185,74 @@ void generic_exec_single(int cpu, struct call_single_data *data, int wait)
 	 * locking and barrier primitives. Generic code isn't really
 	 * equipped to do the right thing...
 	 */
-	if (ipi)
+	if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu)))
 		arch_send_call_function_single_ipi(cpu);
 
 	if (wait)
-		csd_lock_wait(data);
+		csd_lock_wait(csd);
+
+	return 0;
 }
 
-/*
- * Invoked by arch to handle an IPI for call function. Must be called with
- * interrupts disabled.
+/**
+ * generic_smp_call_function_single_interrupt - Execute SMP IPI callbacks
+ *
+ * Invoked by arch to handle an IPI for call function single.
+ * Must be called with interrupts disabled.
  */
-void generic_smp_call_function_interrupt(void)
+void generic_smp_call_function_single_interrupt(void)
 {
-	struct call_function_data *data;
-	int cpu = smp_processor_id();
-
-	/*
-	 * Shouldn't receive this interrupt on a cpu that is not yet online.
-	 */
-	WARN_ON_ONCE(!cpu_online(cpu));
-
-	/*
-	 * Ensure entry is visible on call_function_queue after we have
-	 * entered the IPI. See comment in smp_call_function_many.
-	 * If we don't have this, then we may miss an entry on the list
-	 * and never get another IPI to process it.
-	 */
-	smp_mb();
-
-	/*
-	 * It's ok to use list_for_each_rcu() here even though we may
-	 * delete 'pos', since list_del_rcu() doesn't clear ->next
-	 */
-	list_for_each_entry_rcu(data, &call_function.queue, csd.list) {
-		int refs;
-		smp_call_func_t func;
-
-		/*
-		 * Since we walk the list without any locks, we might
-		 * see an entry that was completed, removed from the
-		 * list and is in the process of being reused.
-		 *
-		 * We must check that the cpu is in the cpumask before
-		 * checking the refs, and both must be set before
-		 * executing the callback on this cpu.
-		 */
-
-		if (!cpumask_test_cpu(cpu, data->cpumask))
-			continue;
-
-		smp_rmb();
-
-		if (atomic_read(&data->refs) == 0)
-			continue;
-
-		func = data->csd.func;		/* save for later warn */
-		func(data->csd.info);
-
-		/*
-		 * If the cpu mask is not still set then func enabled
-		 * interrupts (BUG), and this cpu took another smp call
-		 * function interrupt and executed func(info) twice
-		 * on this cpu.  That nested execution decremented refs.
-		 */
-		if (!cpumask_test_and_clear_cpu(cpu, data->cpumask)) {
-			WARN(1, "%pf enabled interrupts and double executed\n", func);
-			continue;
-		}
-
-		refs = atomic_dec_return(&data->refs);
-		WARN_ON(refs < 0);
-
-		if (refs)
-			continue;
-
-		WARN_ON(!cpumask_empty(data->cpumask));
-
-		raw_spin_lock(&call_function.lock);
-		list_del_rcu(&data->csd.list);
-		raw_spin_unlock(&call_function.lock);
-
-		csd_unlock(&data->csd);
-	}
-
+	flush_smp_call_function_queue(true);
 }
 
-/*
- * Invoked by arch to handle an IPI for call function single. Must be
- * called from the arch with interrupts disabled.
+/**
+ * flush_smp_call_function_queue - Flush pending smp-call-function callbacks
+ *
+ * @warn_cpu_offline: If set to 'true', warn if callbacks were queued on an
+ *		      offline CPU. Skip this check if set to 'false'.
+ *
+ * Flush any pending smp-call-function callbacks queued on this CPU. This is
+ * invoked by the generic IPI handler, as well as by a CPU about to go offline,
+ * to ensure that all pending IPI callbacks are run before it goes completely
+ * offline.
+ *
+ * Loop through the call_single_queue and run all the queued callbacks.
+ * Must be called with interrupts disabled.
  */
-void generic_smp_call_function_single_interrupt(void)
+static void flush_smp_call_function_queue(bool warn_cpu_offline)
 {
-	struct call_single_queue *q = &__get_cpu_var(call_single_queue);
-	unsigned int data_flags;
-	LIST_HEAD(list);
+	struct llist_head *head;
+	struct llist_node *entry;
+	struct call_single_data *csd, *csd_next;
+	static bool warned;
 
-	/*
-	 * Shouldn't receive this interrupt on a cpu that is not yet online.
-	 */
-	WARN_ON_ONCE(!cpu_online(smp_processor_id()));
+	WARN_ON(!irqs_disabled());
 
-	raw_spin_lock(&q->lock);
-	list_replace_init(&q->list, &list);
-	raw_spin_unlock(&q->lock);
+	head = &__get_cpu_var(call_single_queue);
+	entry = llist_del_all(head);
+	entry = llist_reverse_order(entry);
 
-	while (!list_empty(&list)) {
-		struct call_single_data *data;
-
-		data = list_entry(list.next, struct call_single_data, list);
-		list_del(&data->list);
+	/* There shouldn't be any pending callbacks on an offline CPU. */
+	if (unlikely(warn_cpu_offline && !cpu_online(smp_processor_id()) &&
+		     !warned && !llist_empty(head))) {
+		warned = true;
+		WARN(1, "IPI on offline CPU %d\n", smp_processor_id());
 
 		/*
-		 * 'data' can be invalid after this call if flags == 0
-		 * (when called through generic_exec_single()),
-		 * so save them away before making the call:
+		 * We don't have to use the _safe() variant here
+		 * because we are not invoking the IPI handlers yet.
 		 */
-		data_flags = data->flags;
-
-		data->func(data->info);
+		llist_for_each_entry(csd, entry, llist)
+			pr_warn("IPI callback %pS sent to offline CPU\n",
+				csd->func);
+	}
 
-		/*
-		 * Unlocked CSDs are valid through generic_exec_single():
-		 */
-		if (data_flags & CSD_FLAG_LOCK)
-			csd_unlock(data);
+	llist_for_each_entry_safe(csd, csd_next, entry, llist) {
+		csd->func(csd->info);
+		csd_unlock(csd);
 	}
 }
 
-static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);
-
 /*
  * smp_call_function_single - Run a function on a specific CPU
  * @func: The function to run. This must be fast and non-blocking.
@@ -297,12 +264,8 @@ static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);
 int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
 			     int wait)
 {
-	struct call_single_data d = {
-		.flags = 0,
-	};
-	unsigned long flags;
 	int this_cpu;
-	int err = 0;
+	int err;
 
 	/*
 	 * prevent preemption and reschedule on another processor,
@@ -319,32 +282,41 @@ int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
 	WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
 		     && !oops_in_progress);
 
-	if (cpu == this_cpu) {
-		local_irq_save(flags);
-		func(info);
-		local_irq_restore(flags);
-	} else {
-		if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) {
-			struct call_single_data *data = &d;
+	err = generic_exec_single(cpu, NULL, func, info, wait);
 
-			if (!wait)
-				data = &__get_cpu_var(csd_data);
+	put_cpu();
 
-			csd_lock(data);
+	return err;
+}
+EXPORT_SYMBOL(smp_call_function_single);
 
-			data->func = func;
-			data->info = info;
-			generic_exec_single(cpu, data, wait);
-		} else {
-			err = -ENXIO;	/* CPU not online */
-		}
-	}
+/**
+ * smp_call_function_single_async(): Run an asynchronous function on a
+ * 			         specific CPU.
+ * @cpu: The CPU to run on.
+ * @csd: Pre-allocated and setup data structure
+ *
+ * Like smp_call_function_single(), but the call is asynchonous and
+ * can thus be done from contexts with disabled interrupts.
+ *
+ * The caller passes his own pre-allocated data structure
+ * (ie: embedded in an object) and is responsible for synchronizing it
+ * such that the IPIs performed on the @csd are strictly serialized.
+ *
+ * NOTE: Be careful, there is unfortunately no current debugging facility to
+ * validate the correctness of this serialization.
+ */
+int smp_call_function_single_async(int cpu, struct call_single_data *csd)
+{
+	int err = 0;
 
-	put_cpu();
+	preempt_disable();
+	err = generic_exec_single(cpu, csd, csd->func, csd->info, 0);
+	preempt_enable();
 
 	return err;
 }
-EXPORT_SYMBOL(smp_call_function_single);
+EXPORT_SYMBOL_GPL(smp_call_function_single_async);
 
 /*
  * smp_call_function_any - Run a function on any of the given cpus
@@ -354,8 +326,6 @@ EXPORT_SYMBOL(smp_call_function_single);
  * @wait: If true, wait until function has completed.
  *
  * Returns 0 on success, else a negative status code (if no cpus were online).
- * Note that @wait will be implicitly turned on in case of allocation failures,
- * since we fall back to on-stack allocation.
  *
  * Selection preference:
  *	1) current cpu if in @mask
@@ -392,43 +362,6 @@ call:
 EXPORT_SYMBOL_GPL(smp_call_function_any);
 
 /**
- * __smp_call_function_single(): Run a function on a specific CPU
- * @cpu: The CPU to run on.
- * @data: Pre-allocated and setup data structure
- * @wait: If true, wait until function has completed on specified CPU.
- *
- * Like smp_call_function_single(), but allow caller to pass in a
- * pre-allocated data structure. Useful for embedding @data inside
- * other structures, for instance.
- */
-void __smp_call_function_single(int cpu, struct call_single_data *data,
-				int wait)
-{
-	unsigned int this_cpu;
-	unsigned long flags;
-
-	this_cpu = get_cpu();
-	/*
-	 * Can deadlock when called with interrupts disabled.
-	 * We allow cpu's that are not yet online though, as no one else can
-	 * send smp call function interrupt to this cpu and as such deadlocks
-	 * can't happen.
-	 */
-	WARN_ON_ONCE(cpu_online(smp_processor_id()) && wait && irqs_disabled()
-		     && !oops_in_progress);
-
-	if (cpu == this_cpu) {
-		local_irq_save(flags);
-		data->func(data->info);
-		local_irq_restore(flags);
-	} else {
-		csd_lock(data);
-		generic_exec_single(cpu, data, wait);
-	}
-	put_cpu();
-}
-
-/**
  * smp_call_function_many(): Run a function on a set of other CPUs.
  * @mask: The set of cpus to run on (only runs on online subset).
  * @func: The function to run. This must be fast and non-blocking.
@@ -445,9 +378,8 @@ void __smp_call_function_single(int cpu, struct call_single_data *data,
 void smp_call_function_many(const struct cpumask *mask,
 			    smp_call_func_t func, void *info, bool wait)
 {
-	struct call_function_data *data;
-	unsigned long flags;
-	int refs, cpu, next_cpu, this_cpu = smp_processor_id();
+	struct call_function_data *cfd;
+	int cpu, next_cpu, this_cpu = smp_processor_id();
 
 	/*
 	 * Can deadlock when called with interrupts disabled.
@@ -478,80 +410,35 @@ void smp_call_function_many(const struct cpumask *mask,
 		return;
 	}
 
-	data = &__get_cpu_var(cfd_data);
-	csd_lock(&data->csd);
+	cfd = &__get_cpu_var(cfd_data);
 
-	/* This BUG_ON verifies our reuse assertions and can be removed */
-	BUG_ON(atomic_read(&data->refs) || !cpumask_empty(data->cpumask));
-
-	/*
-	 * The global call function queue list add and delete are protected
-	 * by a lock, but the list is traversed without any lock, relying
-	 * on the rcu list add and delete to allow safe concurrent traversal.
-	 * We reuse the call function data without waiting for any grace
-	 * period after some other cpu removes it from the global queue.
-	 * This means a cpu might find our data block as it is being
-	 * filled out.
-	 *
-	 * We hold off the interrupt handler on the other cpu by
-	 * ordering our writes to the cpu mask vs our setting of the
-	 * refs counter.  We assert only the cpu owning the data block
-	 * will set a bit in cpumask, and each bit will only be cleared
-	 * by the subject cpu.  Each cpu must first find its bit is
-	 * set and then check that refs is set indicating the element is
-	 * ready to be processed, otherwise it must skip the entry.
-	 *
-	 * On the previous iteration refs was set to 0 by another cpu.
-	 * To avoid the use of transitivity, set the counter to 0 here
-	 * so the wmb will pair with the rmb in the interrupt handler.
-	 */
-	atomic_set(&data->refs, 0);	/* convert 3rd to 1st party write */
-
-	data->csd.func = func;
-	data->csd.info = info;
-
-	/* Ensure 0 refs is visible before mask.  Also orders func and info */
-	smp_wmb();
-
-	/* We rely on the "and" being processed before the store */
-	cpumask_and(data->cpumask, mask, cpu_online_mask);
-	cpumask_clear_cpu(this_cpu, data->cpumask);
-	refs = cpumask_weight(data->cpumask);
+	cpumask_and(cfd->cpumask, mask, cpu_online_mask);
+	cpumask_clear_cpu(this_cpu, cfd->cpumask);
 
 	/* Some callers race with other cpus changing the passed mask */
-	if (unlikely(!refs)) {
-		csd_unlock(&data->csd);
+	if (unlikely(!cpumask_weight(cfd->cpumask)))
 		return;
-	}
 
-	raw_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);
-	/*
-	 * We rely on the wmb() in list_add_rcu to complete our writes
-	 * to the cpumask before this write to refs, which indicates
-	 * data is on the list and is ready to be processed.
-	 */
-	atomic_set(&data->refs, refs);
-	raw_spin_unlock_irqrestore(&call_function.lock, flags);
+	for_each_cpu(cpu, cfd->cpumask) {
+		struct call_single_data *csd = per_cpu_ptr(cfd->csd, cpu);
 
-	/*
-	 * Make the list addition visible before sending the ipi.
-	 * (IPIs must obey or appear to obey normal Linux cache
-	 * coherency rules -- see comment in generic_exec_single).
-	 */
-	smp_mb();
+		csd_lock(csd);
+		csd->func = func;
+		csd->info = info;
+		llist_add(&csd->llist, &per_cpu(call_single_queue, cpu));
+	}
 
 	/* Send a message to all CPUs in the map */
-	arch_send_call_function_ipi_mask(data->cpumask);
+	arch_send_call_function_ipi_mask(cfd->cpumask);
 
-	/* Optionally wait for the CPUs to complete */
-	if (wait)
-		csd_lock_wait(&data->csd);
+	if (wait) {
+		for_each_cpu(cpu, cfd->cpumask) {
+			struct call_single_data *csd;
+
+			csd = per_cpu_ptr(cfd->csd, cpu);
+			csd_lock_wait(csd);
+		}
+	}
 }
 EXPORT_SYMBOL(smp_call_function_many);
 
@@ -580,27 +467,6 @@ int smp_call_function(smp_call_func_t func, void *info, int wait)
 }
 EXPORT_SYMBOL(smp_call_function);
 
-void ipi_call_lock(void)
-{
-	raw_spin_lock(&call_function.lock);
-}
-
-void ipi_call_unlock(void)
-{
-	raw_spin_unlock(&call_function.lock);
-}
-
-void ipi_call_lock_irq(void)
-{
-	raw_spin_lock_irq(&call_function.lock);
-}
-
-void ipi_call_unlock_irq(void)
-{
-	raw_spin_unlock_irq(&call_function.lock);
-}
-#endif /* USE_GENERIC_SMP_HELPERS */
-
 /* Setup configured maximum number of CPUs to activate */
 unsigned int setup_max_cpus = NR_CPUS;
 EXPORT_SYMBOL(setup_max_cpus);
@@ -664,11 +530,18 @@ void __init setup_nr_cpu_ids(void)
 	nr_cpu_ids = find_last_bit(cpumask_bits(cpu_possible_mask),NR_CPUS) + 1;
 }
 
+void __weak smp_announce(void)
+{
+	printk(KERN_INFO "Brought up %d CPUs\n", num_online_cpus());
+}
+
 /* Called by boot processor to activate the rest. */
 void __init smp_init(void)
 {
 	unsigned int cpu;
 
+	idle_threads_init();
+
 	/* FIXME: This should be done in userspace --RR */
 	for_each_present_cpu(cpu) {
 		if (num_online_cpus() >= setup_max_cpus)
@@ -678,7 +551,7 @@ void __init smp_init(void)
 	}
 
 	/* Any cleanup work */
-	printk(KERN_INFO "Brought up %ld CPUs\n", (long)num_online_cpus());
+	smp_announce();
 	smp_cpus_done(setup_max_cpus);
 }
 
@@ -701,3 +574,119 @@ int on_each_cpu(void (*func) (void *info), void *info, int wait)
 	return ret;
 }
 EXPORT_SYMBOL(on_each_cpu);
+
+/**
+ * on_each_cpu_mask(): Run a function on processors specified by
+ * cpumask, which may include the local processor.
+ * @mask: The set of cpus to run on (only runs on online subset).
+ * @func: The function to run. This must be fast and non-blocking.
+ * @info: An arbitrary pointer to pass to the function.
+ * @wait: If true, wait (atomically) until function has completed
+ *        on other CPUs.
+ *
+ * If @wait is true, then returns once @func has returned.
+ *
+ * You must not call this function with disabled interrupts or from a
+ * hardware interrupt handler or from a bottom half handler.  The
+ * exception is that it may be used during early boot while
+ * early_boot_irqs_disabled is set.
+ */
+void on_each_cpu_mask(const struct cpumask *mask, smp_call_func_t func,
+			void *info, bool wait)
+{
+	int cpu = get_cpu();
+
+	smp_call_function_many(mask, func, info, wait);
+	if (cpumask_test_cpu(cpu, mask)) {
+		unsigned long flags;
+		local_irq_save(flags);
+		func(info);
+		local_irq_restore(flags);
+	}
+	put_cpu();
+}
+EXPORT_SYMBOL(on_each_cpu_mask);
+
+/*
+ * on_each_cpu_cond(): Call a function on each processor for which
+ * the supplied function cond_func returns true, optionally waiting
+ * for all the required CPUs to finish. This may include the local
+ * processor.
+ * @cond_func:	A callback function that is passed a cpu id and
+ *		the the info parameter. The function is called
+ *		with preemption disabled. The function should
+ *		return a blooean value indicating whether to IPI
+ *		the specified CPU.
+ * @func:	The function to run on all applicable CPUs.
+ *		This must be fast and non-blocking.
+ * @info:	An arbitrary pointer to pass to both functions.
+ * @wait:	If true, wait (atomically) until function has
+ *		completed on other CPUs.
+ * @gfp_flags:	GFP flags to use when allocating the cpumask
+ *		used internally by the function.
+ *
+ * The function might sleep if the GFP flags indicates a non
+ * atomic allocation is allowed.
+ *
+ * Preemption is disabled to protect against CPUs going offline but not online.
+ * CPUs going online during the call will not be seen or sent an IPI.
+ *
+ * You must not call this function with disabled interrupts or
+ * from a hardware interrupt handler or from a bottom half handler.
+ */
+void on_each_cpu_cond(bool (*cond_func)(int cpu, void *info),
+			smp_call_func_t func, void *info, bool wait,
+			gfp_t gfp_flags)
+{
+	cpumask_var_t cpus;
+	int cpu, ret;
+
+	might_sleep_if(gfp_flags & __GFP_WAIT);
+
+	if (likely(zalloc_cpumask_var(&cpus, (gfp_flags|__GFP_NOWARN)))) {
+		preempt_disable();
+		for_each_online_cpu(cpu)
+			if (cond_func(cpu, info))
+				cpumask_set_cpu(cpu, cpus);
+		on_each_cpu_mask(cpus, func, info, wait);
+		preempt_enable();
+		free_cpumask_var(cpus);
+	} else {
+		/*
+		 * No free cpumask, bother. No matter, we'll
+		 * just have to IPI them one by one.
+		 */
+		preempt_disable();
+		for_each_online_cpu(cpu)
+			if (cond_func(cpu, info)) {
+				ret = smp_call_function_single(cpu, func,
+								info, wait);
+				WARN_ON_ONCE(!ret);
+			}
+		preempt_enable();
+	}
+}
+EXPORT_SYMBOL(on_each_cpu_cond);
+
+static void do_nothing(void *unused)
+{
+}
+
+/**
+ * kick_all_cpus_sync - Force all cpus out of idle
+ *
+ * Used to synchronize the update of pm_idle function pointer. It's
+ * called after the pointer is updated and returns after the dummy
+ * callback function has been executed on all cpus. The execution of
+ * the function can only happen on the remote cpus after they have
+ * left the idle function which had been called via pm_idle function
+ * pointer. So it's guaranteed that nothing uses the previous pointer
+ * anymore.
+ */
+void kick_all_cpus_sync(void)
+{
+	/* Make sure the change is visible before we kick the cpus */
+	smp_mb();
+	smp_call_function(do_nothing, NULL, 1);
+}
+EXPORT_SYMBOL_GPL(kick_all_cpus_sync);