mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-28 20:02:17 +00:00
![Rusty Russell](/assets/img/avatar_default.png)
Now everyone is converted to arch_send_call_function_ipi_mask, remove the shim and the #defines. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
480 lines
12 KiB
C
480 lines
12 KiB
C
/*
|
|
* Generic helpers for smp ipi calls
|
|
*
|
|
* (C) Jens Axboe <jens.axboe@oracle.com> 2008
|
|
*/
|
|
#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 DEFINE_PER_CPU(struct call_single_queue, call_single_queue);
|
|
|
|
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),
|
|
};
|
|
|
|
enum {
|
|
CSD_FLAG_LOCK = 0x01,
|
|
};
|
|
|
|
struct call_function_data {
|
|
struct call_single_data csd;
|
|
atomic_t refs;
|
|
cpumask_var_t cpumask;
|
|
};
|
|
|
|
struct call_single_queue {
|
|
struct list_head list;
|
|
spinlock_t lock;
|
|
};
|
|
|
|
static DEFINE_PER_CPU(struct call_function_data, cfd_data);
|
|
|
|
static int
|
|
hotplug_cfd(struct notifier_block *nfb, unsigned long action, void *hcpu)
|
|
{
|
|
long cpu = (long)hcpu;
|
|
struct call_function_data *cfd = &per_cpu(cfd_data, cpu);
|
|
|
|
switch (action) {
|
|
case CPU_UP_PREPARE:
|
|
case CPU_UP_PREPARE_FROZEN:
|
|
if (!zalloc_cpumask_var_node(&cfd->cpumask, GFP_KERNEL,
|
|
cpu_to_node(cpu)))
|
|
return NOTIFY_BAD;
|
|
break;
|
|
|
|
#ifdef CONFIG_HOTPLUG_CPU
|
|
case CPU_UP_CANCELED:
|
|
case CPU_UP_CANCELED_FROZEN:
|
|
|
|
case CPU_DEAD:
|
|
case CPU_DEAD_FROZEN:
|
|
free_cpumask_var(cfd->cpumask);
|
|
break;
|
|
#endif
|
|
};
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
static struct notifier_block __cpuinitdata hotplug_cfd_notifier = {
|
|
.notifier_call = hotplug_cfd,
|
|
};
|
|
|
|
static int __cpuinit init_call_single_data(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);
|
|
|
|
spin_lock_init(&q->lock);
|
|
INIT_LIST_HEAD(&q->list);
|
|
}
|
|
|
|
hotplug_cfd(&hotplug_cfd_notifier, CPU_UP_PREPARE, cpu);
|
|
register_cpu_notifier(&hotplug_cfd_notifier);
|
|
|
|
return 0;
|
|
}
|
|
early_initcall(init_call_single_data);
|
|
|
|
/*
|
|
* 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.
|
|
*/
|
|
static void csd_lock_wait(struct call_single_data *data)
|
|
{
|
|
while (data->flags & CSD_FLAG_LOCK)
|
|
cpu_relax();
|
|
}
|
|
|
|
static void csd_lock(struct call_single_data *data)
|
|
{
|
|
csd_lock_wait(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:
|
|
*/
|
|
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:
|
|
*/
|
|
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.
|
|
*/
|
|
static
|
|
void generic_exec_single(int cpu, struct call_single_data *data, int wait)
|
|
{
|
|
struct call_single_queue *dst = &per_cpu(call_single_queue, cpu);
|
|
unsigned long flags;
|
|
int ipi;
|
|
|
|
spin_lock_irqsave(&dst->lock, flags);
|
|
ipi = list_empty(&dst->list);
|
|
list_add_tail(&data->list, &dst->list);
|
|
spin_unlock_irqrestore(&dst->lock, flags);
|
|
|
|
/*
|
|
* The list addition should be visible before sending the IPI
|
|
* handler locks the list to pull the entry off it because of
|
|
* normal cache coherency rules implied by spinlocks.
|
|
*
|
|
* 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...
|
|
*/
|
|
if (ipi)
|
|
arch_send_call_function_single_ipi(cpu);
|
|
|
|
if (wait)
|
|
csd_lock_wait(data);
|
|
}
|
|
|
|
/*
|
|
* Invoked by arch to handle an IPI for call function. Must be called with
|
|
* interrupts disabled.
|
|
*/
|
|
void generic_smp_call_function_interrupt(void)
|
|
{
|
|
struct call_function_data *data;
|
|
int cpu = get_cpu();
|
|
|
|
/*
|
|
* 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;
|
|
|
|
if (!cpumask_test_and_clear_cpu(cpu, data->cpumask))
|
|
continue;
|
|
|
|
data->csd.func(data->csd.info);
|
|
|
|
refs = atomic_dec_return(&data->refs);
|
|
WARN_ON(refs < 0);
|
|
if (!refs) {
|
|
spin_lock(&call_function.lock);
|
|
list_del_rcu(&data->csd.list);
|
|
spin_unlock(&call_function.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.
|
|
*/
|
|
void generic_smp_call_function_single_interrupt(void)
|
|
{
|
|
struct call_single_queue *q = &__get_cpu_var(call_single_queue);
|
|
unsigned int data_flags;
|
|
LIST_HEAD(list);
|
|
|
|
/*
|
|
* Shouldn't receive this interrupt on a cpu that is not yet online.
|
|
*/
|
|
WARN_ON_ONCE(!cpu_online(smp_processor_id()));
|
|
|
|
spin_lock(&q->lock);
|
|
list_replace_init(&q->list, &list);
|
|
spin_unlock(&q->lock);
|
|
|
|
while (!list_empty(&list)) {
|
|
struct call_single_data *data;
|
|
|
|
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_flags = data->flags;
|
|
|
|
data->func(data->info);
|
|
|
|
/*
|
|
* Unlocked CSDs are valid through generic_exec_single():
|
|
*/
|
|
if (data_flags & CSD_FLAG_LOCK)
|
|
csd_unlock(data);
|
|
}
|
|
}
|
|
|
|
static DEFINE_PER_CPU(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.
|
|
* @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.
|
|
*/
|
|
int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
|
|
int wait)
|
|
{
|
|
struct call_single_data d = {
|
|
.flags = 0,
|
|
};
|
|
unsigned long flags;
|
|
int this_cpu;
|
|
int err = 0;
|
|
|
|
/*
|
|
* 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 == 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;
|
|
|
|
if (!wait)
|
|
data = &__get_cpu_var(csd_data);
|
|
|
|
csd_lock(data);
|
|
|
|
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_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.
|
|
*/
|
|
void __smp_call_function_single(int cpu, struct call_single_data *data,
|
|
int wait)
|
|
{
|
|
csd_lock(data);
|
|
|
|
/*
|
|
* 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);
|
|
}
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* 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.
|
|
*
|
|
* 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)
|
|
{
|
|
struct call_function_data *data;
|
|
unsigned long flags;
|
|
int cpu, next_cpu, this_cpu = smp_processor_id();
|
|
|
|
/*
|
|
* 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. */
|
|
cpu = cpumask_first_and(mask, cpu_online_mask);
|
|
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 == this_cpu)
|
|
next_cpu = cpumask_next_and(next_cpu, mask, cpu_online_mask);
|
|
|
|
/* Fastpath: do that cpu by itself. */
|
|
if (next_cpu >= nr_cpu_ids) {
|
|
smp_call_function_single(cpu, func, info, wait);
|
|
return;
|
|
}
|
|
|
|
data = &__get_cpu_var(cfd_data);
|
|
csd_lock(&data->csd);
|
|
|
|
data->csd.func = func;
|
|
data->csd.info = info;
|
|
cpumask_and(data->cpumask, mask, cpu_online_mask);
|
|
cpumask_clear_cpu(this_cpu, data->cpumask);
|
|
atomic_set(&data->refs, cpumask_weight(data->cpumask));
|
|
|
|
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);
|
|
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).
|
|
*/
|
|
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 */
|
|
if (wait)
|
|
csd_lock_wait(&data->csd);
|
|
}
|
|
EXPORT_SYMBOL(smp_call_function_many);
|
|
|
|
/**
|
|
* 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.
|
|
*
|
|
* 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.
|
|
*
|
|
* You must not call this function with disabled interrupts or from a
|
|
* hardware interrupt handler or from a bottom half handler.
|
|
*/
|
|
int smp_call_function(void (*func)(void *), void *info, int wait)
|
|
{
|
|
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);
|
|
}
|
|
|
|
void ipi_call_unlock(void)
|
|
{
|
|
spin_unlock(&call_function.lock);
|
|
}
|
|
|
|
void ipi_call_lock_irq(void)
|
|
{
|
|
spin_lock_irq(&call_function.lock);
|
|
}
|
|
|
|
void ipi_call_unlock_irq(void)
|
|
{
|
|
spin_unlock_irq(&call_function.lock);
|
|
}
|