* Generic helpers for smp ipi calls
*
* (C) Jens Axboe <jens.axboe@oracle.com> 2008
- *
*/
-#include <linux/init.h>
-#include <linux/module.h>
-#include <linux/percpu.h>
#include <linux/rcupdate.h>
#include <linux/rculist.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/percpu.h>
+#include <linux/init.h>
#include <linux/smp.h>
#include <linux/cpu.h>
static struct {
struct list_head queue;
- spinlock_t lock;
-} call_function __cacheline_aligned_in_smp = {
- .queue = LIST_HEAD_INIT(call_function.queue),
- .lock = __SPIN_LOCK_UNLOCKED(call_function.lock),
-};
+ 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),
+ };
enum {
CSD_FLAG_LOCK = 0x01,
};
struct call_function_data {
- struct call_single_data csd;
- spinlock_t lock;
- unsigned int refs;
- cpumask_var_t cpumask;
+ struct call_single_data csd;
+ atomic_t refs;
+ cpumask_var_t cpumask;
};
struct call_single_queue {
- struct list_head list;
- spinlock_t lock;
+ struct list_head list;
+ raw_spinlock_t lock;
};
-static DEFINE_PER_CPU(struct call_function_data, cfd_data) = {
- .lock = __SPIN_LOCK_UNLOCKED(cfd_data.lock),
-};
+static DEFINE_PER_CPU(struct call_function_data, cfd_data);
static int
hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
switch (action) {
case CPU_UP_PREPARE:
case CPU_UP_PREPARE_FROZEN:
- if (!alloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL,
+ if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL,
cpu_to_node(cpu)))
return NOTIFY_BAD;
break;
-#ifdef CONFIG_CPU_HOTPLUG
+#ifdef CONFIG_HOTPLUG_CPU
case CPU_UP_CANCELED:
case CPU_UP_CANCELED_FROZEN:
}
static struct notifier_block __cpuinitdata hotplug_cfd_notifier = {
- .notifier_call = hotplug_cfd,
+ .notifier_call = hotplug_cfd,
};
static int __cpuinit init_call_single_data(void)
for_each_possible_cpu(i) {
struct call_single_queue *q = &per_cpu(call_single_queue, i);
- spin_lock_init(&q->lock);
+ raw_spin_lock_init(&q->lock);
INIT_LIST_HEAD(&q->list);
}
/*
* csd_lock/csd_unlock used to serialize access to per-cpu csd resources
*
- * For non-synchronous ipi calls the csd can still be in use by the previous
- * function call. For multi-cpu calls its even more interesting as we'll have
- * to ensure no other cpu is observing our csd.
+ * For non-synchronous ipi calls the csd can still be in use by the
+ * 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)
{
data->flags = CSD_FLAG_LOCK;
/*
- * prevent CPU from reordering the above assignment to ->flags
- * with any subsequent assignments to other fields of the
- * specified call_single_data structure.
+ * prevent CPU from reordering the above assignment
+ * to ->flags with any subsequent assignments to other
+ * fields of the specified call_single_data structure:
*/
-
smp_mb();
}
static void csd_unlock(struct call_single_data *data)
{
WARN_ON(!(data->flags & CSD_FLAG_LOCK));
+
/*
- * ensure we're all done before releasing data
+ * ensure we're all done before releasing data:
*/
smp_mb();
+
data->flags &= ~CSD_FLAG_LOCK;
}
/*
- * Insert a previously allocated call_single_data element for execution
- * on the given CPU. data must already have ->func, ->info, and ->flags set.
+ * 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)
unsigned long flags;
int ipi;
- spin_lock_irqsave(&dst->lock, flags);
+ raw_spin_lock_irqsave(&dst->lock, flags);
ipi = list_empty(&dst->list);
list_add_tail(&data->list, &dst->list);
- spin_unlock_irqrestore(&dst->lock, flags);
+ raw_spin_unlock_irqrestore(&dst->lock, flags);
/*
* The list addition should be visible before sending the IPI
* If IPIs can go out of order to the cache coherency protocol
* in an architecture, sufficient synchronisation should be added
* to arch code to make it appear to obey cache coherency WRT
- * locking and barrier primitives. Generic code isn't really equipped
- * to do the right thing...
+ * locking and barrier primitives. Generic code isn't really
+ * equipped to do the right thing...
*/
-
if (ipi)
arch_send_call_function_single_ipi(cpu);
void generic_smp_call_function_interrupt(void)
{
struct call_function_data *data;
- int cpu = get_cpu();
+ 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
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
+ * 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;
- spin_lock(&data->lock);
- if (!cpumask_test_cpu(cpu, data->cpumask)) {
- spin_unlock(&data->lock);
+ if (!cpumask_test_and_clear_cpu(cpu, data->cpumask))
continue;
- }
- cpumask_clear_cpu(cpu, data->cpumask);
- spin_unlock(&data->lock);
data->csd.func(data->csd.info);
- spin_lock(&data->lock);
- WARN_ON(data->refs == 0);
- refs = --data->refs;
+ refs = atomic_dec_return(&data->refs);
+ WARN_ON(refs < 0);
if (!refs) {
- spin_lock(&call_function.lock);
+ raw_spin_lock(&call_function.lock);
list_del_rcu(&data->csd.list);
- spin_unlock(&call_function.lock);
+ raw_spin_unlock(&call_function.lock);
}
- spin_unlock(&data->lock);
if (refs)
continue;
csd_unlock(&data->csd);
}
- put_cpu();
}
/*
- * Invoked by arch to handle an IPI for call function single. Must be called
- * from the arch with interrupts disabled.
+ * Invoked by arch to handle an IPI for call function single. Must be
+ * called from the arch with interrupts disabled.
*/
void generic_smp_call_function_single_interrupt(void)
{
struct call_single_queue *q = &__get_cpu_var(call_single_queue);
- LIST_HEAD(list);
unsigned int data_flags;
+ LIST_HEAD(list);
- spin_lock(&q->lock);
+ /*
+ * Shouldn't receive this interrupt on a cpu that is not yet online.
+ */
+ WARN_ON_ONCE(!cpu_online(smp_processor_id()));
+
+ raw_spin_lock(&q->lock);
list_replace_init(&q->list, &list);
- spin_unlock(&q->lock);
+ raw_spin_unlock(&q->lock);
while (!list_empty(&list)) {
struct call_single_data *data;
- data = list_entry(list.next, struct call_single_data,
- list);
+ data = list_entry(list.next, struct call_single_data, list);
list_del(&data->list);
/*
- * 'data' can be invalid after this call if
- * flags == 0 (when called through
- * generic_exec_single(), so save them away before
- * making the call.
+ * 'data' can be invalid after this call if flags == 0
+ * (when called through generic_exec_single()),
+ * so save them away before making the call:
*/
data_flags = data->flags;
data->func(data->info);
/*
- * Unlocked CSDs are valid through generic_exec_single()
+ * Unlocked CSDs are valid through generic_exec_single():
*/
if (data_flags & CSD_FLAG_LOCK)
csd_unlock(data);
* @info: An arbitrary pointer to pass to the function.
* @wait: If true, wait until function has completed on other CPUs.
*
- * Returns 0 on success, else a negative status code. Note that @wait
- * will be implicitly turned on in case of allocation failures, since
- * we fall back to on-stack allocation.
+ * Returns 0 on success, else a negative status code.
*/
int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
int wait)
.flags = 0,
};
unsigned long flags;
- /* prevent preemption and reschedule on another processor,
- as well as CPU removal */
- int me = get_cpu();
+ int this_cpu;
int err = 0;
- /* Can deadlock when called with interrupts disabled */
- WARN_ON(irqs_disabled());
+ /*
+ * prevent preemption and reschedule on another processor,
+ * as well as CPU removal
+ */
+ 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(this_cpu) && irqs_disabled()
+ && !oops_in_progress);
- if (cpu == me) {
+ 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;
+ } else {
+ if ((unsigned)cpu < nr_cpu_ids && cpu_online(cpu)) {
+ struct call_single_data *data = &d;
- if (!wait)
- data = &__get_cpu_var(csd_data);
+ if (!wait)
+ data = &__get_cpu_var(csd_data);
- csd_lock(data);
+ csd_lock(data);
- data->func = func;
- data->info = info;
- generic_exec_single(cpu, data, wait);
- } else {
- err = -ENXIO; /* CPU not online */
+ data->func = func;
+ data->info = info;
+ generic_exec_single(cpu, data, wait);
+ } else {
+ err = -ENXIO; /* CPU not online */
+ }
}
put_cpu();
+
return err;
}
EXPORT_SYMBOL(smp_call_function_single);
+/*
+ * smp_call_function_any - Run a function on any of the given cpus
+ * @mask: The mask of cpus it can run on.
+ * @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 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
+ * 2) any cpu of current node if in @mask
+ * 3) any other online cpu in @mask
+ */
+int smp_call_function_any(const struct cpumask *mask,
+ void (*func)(void *info), void *info, int wait)
+{
+ unsigned int cpu;
+ const struct cpumask *nodemask;
+ int ret;
+
+ /* Try for same CPU (cheapest) */
+ cpu = get_cpu();
+ if (cpumask_test_cpu(cpu, mask))
+ goto call;
+
+ /* Try for same node. */
+ nodemask = cpumask_of_node(cpu_to_node(cpu));
+ for (cpu = cpumask_first_and(nodemask, mask); cpu < nr_cpu_ids;
+ cpu = cpumask_next_and(cpu, nodemask, mask)) {
+ if (cpu_online(cpu))
+ goto call;
+ }
+
+ /* Any online will do: smp_call_function_single handles nr_cpu_ids. */
+ cpu = cpumask_any_and(mask, cpu_online_mask);
+call:
+ ret = smp_call_function_single(cpu, func, info, wait);
+ put_cpu();
+ return ret;
+}
+EXPORT_SYMBOL_GPL(smp_call_function_any);
+
/**
* __smp_call_function_single(): Run a function on another CPU
* @cpu: The CPU to run on.
* @data: Pre-allocated and setup data structure
*
- * 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.
- *
+ * 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)
{
csd_lock(data);
- /* Can deadlock when called with interrupts disabled */
- WARN_ON(wait && irqs_disabled());
+ /*
+ * 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);
generic_exec_single(cpu, data, wait);
}
-/* FIXME: Shim for archs using old arch_send_call_function_ipi API. */
-#ifndef arch_send_call_function_ipi_mask
-#define arch_send_call_function_ipi_mask(maskp) \
- arch_send_call_function_ipi(*(maskp))
-#endif
-
/**
* 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.
* @info: An arbitrary pointer to pass to the function.
- * @wait: If true, wait (atomically) until function has completed on other CPUs.
+ * @wait: If true, wait (atomically) until function has completed
+ * on other CPUs.
*
- * If @wait is true, then returns once @func has returned. Note that @wait
- * will be implicitly turned on in case of allocation failures, since
- * we fall back to on-stack allocation.
+ * 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. Preemption
* must be disabled when calling this function.
*/
void smp_call_function_many(const struct cpumask *mask,
- void (*func)(void *), void *info,
- bool wait)
+ void (*func)(void *), void *info, bool wait)
{
struct call_function_data *data;
unsigned long flags;
- int cpu, next_cpu, me = smp_processor_id();
+ int cpu, next_cpu, this_cpu = smp_processor_id();
- /* Can deadlock when called with interrupts disabled */
- WARN_ON(irqs_disabled());
+ /*
+ * 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(this_cpu) && irqs_disabled()
+ && !oops_in_progress);
- /* So, what's a CPU they want? Ignoring this one. */
+ /* So, what's a CPU they want? Ignoring this one. */
cpu = cpumask_first_and(mask, cpu_online_mask);
- if (cpu == me)
+ if (cpu == this_cpu)
cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
+
/* No online cpus? We're done. */
if (cpu >= nr_cpu_ids)
return;
/* Do we have another CPU which isn't us? */
next_cpu = cpumask_next_and(cpu, mask, cpu_online_mask);
- if (next_cpu == me)
+ if (next_cpu == this_cpu)
next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask);
/* Fastpath: do that cpu by itself. */
data = &__get_cpu_var(cfd_data);
csd_lock(&data->csd);
- spin_lock_irqsave(&data->lock, flags);
data->csd.func = func;
data->csd.info = info;
cpumask_and(data->cpumask, mask, cpu_online_mask);
- cpumask_clear_cpu(me, data->cpumask);
- data->refs = cpumask_weight(data->cpumask);
+ cpumask_clear_cpu(this_cpu, data->cpumask);
+ atomic_set(&data->refs, cpumask_weight(data->cpumask));
- spin_lock(&call_function.lock);
+ 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.
+ * 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);
- spin_unlock(&call_function.lock);
- spin_unlock_irqrestore(&data->lock, flags);
+ raw_spin_unlock_irqrestore(&call_function.lock, flags);
/*
* 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).
+ * (IPIs must obey or appear to obey normal Linux cache
+ * coherency rules -- see comment in generic_exec_single).
*/
smp_mb();
/* Send a message to all CPUs in the map */
arch_send_call_function_ipi_mask(data->cpumask);
- /* optionally wait for the CPUs to complete */
+ /* Optionally wait for the CPUs to complete */
if (wait)
csd_lock_wait(&data->csd);
}
* smp_call_function(): Run a function on all other CPUs.
* @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.
+ * @wait: If true, wait (atomically) until function has completed
+ * on other CPUs.
*
* Returns 0.
*
* If @wait is true, then returns once @func has returned; otherwise
- * it returns just before the target cpu calls @func. In case of allocation
- * failure, @wait will be implicitly turned on.
+ * it returns just before the target cpu calls @func.
*
* You must not call this function with disabled interrupts or from a
* hardware interrupt handler or from a bottom half handler.
preempt_disable();
smp_call_function_many(cpu_online_mask, func, info, wait);
preempt_enable();
+
return 0;
}
EXPORT_SYMBOL(smp_call_function);
void ipi_call_lock(void)
{
- spin_lock(&call_function.lock);
+ raw_spin_lock(&call_function.lock);
}
void ipi_call_unlock(void)
{
- spin_unlock(&call_function.lock);
+ raw_spin_unlock(&call_function.lock);
}
void ipi_call_lock_irq(void)
{
- spin_lock_irq(&call_function.lock);
+ raw_spin_lock_irq(&call_function.lock);
}
void ipi_call_unlock_irq(void)
{
- spin_unlock_irq(&call_function.lock);
+ raw_spin_unlock_irq(&call_function.lock);
}
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff