#include <linux/gfp.h>
#include <linux/smp.h>
#include <linux/cpu.h>
+#include <linux/sched.h>
#include "smpboot.h"
enum {
CSD_FLAG_LOCK = 0x01,
- CSD_FLAG_WAIT = 0x02,
+ CSD_FLAG_SYNCHRONOUS = 0x02,
};
struct call_function_data {
*/
static void csd_lock_wait(struct call_single_data *csd)
{
- while (csd->flags & CSD_FLAG_LOCK)
+ while (smp_load_acquire(&csd->flags) & CSD_FLAG_LOCK)
cpu_relax();
}
* to ->flags with any subsequent assignments to other
* fields of the specified call_single_data structure:
*/
- smp_mb();
+ smp_wmb();
}
static void csd_unlock(struct call_single_data *csd)
{
- WARN_ON((csd->flags & CSD_FLAG_WAIT) && !(csd->flags & CSD_FLAG_LOCK));
+ WARN_ON(!(csd->flags & CSD_FLAG_LOCK));
/*
* ensure we're all done before releasing data:
*/
- smp_mb();
-
- csd->flags &= ~CSD_FLAG_LOCK;
+ smp_store_release(&csd->flags, 0);
}
static DEFINE_PER_CPU_SHARED_ALIGNED(struct call_single_data, csd_data);
* ->func, ->info, and ->flags set.
*/
static int generic_exec_single(int cpu, struct call_single_data *csd,
- smp_call_func_t func, void *info, int wait)
+ smp_call_func_t func, void *info)
{
- struct call_single_data csd_stack = { .flags = 0 };
- unsigned long flags;
-
-
if (cpu == smp_processor_id()) {
+ unsigned long flags;
+
+ /*
+ * We can unlock early even for the synchronous on-stack case,
+ * since we're doing this from the same CPU..
+ */
+ csd_unlock(csd);
local_irq_save(flags);
func(info);
local_irq_restore(flags);
}
- if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu))
+ if ((unsigned)cpu >= nr_cpu_ids || !cpu_online(cpu)) {
+ csd_unlock(csd);
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
* handler locks the list to pull the entry off it because of
if (llist_add(&csd->llist, &per_cpu(call_single_queue, cpu)))
arch_send_call_function_single_ipi(cpu);
- if (wait)
- csd_lock_wait(csd);
-
return 0;
}
WARN_ON(!irqs_disabled());
- head = &__get_cpu_var(call_single_queue);
+ head = this_cpu_ptr(&call_single_queue);
entry = llist_del_all(head);
entry = llist_reverse_order(entry);
}
llist_for_each_entry_safe(csd, csd_next, entry, llist) {
- csd->func(csd->info);
- csd_unlock(csd);
+ smp_call_func_t func = csd->func;
+ void *info = csd->info;
+
+ /* Do we wait until *after* callback? */
+ if (csd->flags & CSD_FLAG_SYNCHRONOUS) {
+ func(info);
+ csd_unlock(csd);
+ } else {
+ csd_unlock(csd);
+ func(info);
+ }
}
/*
int smp_call_function_single(int cpu, smp_call_func_t func, void *info,
int wait)
{
+ struct call_single_data *csd;
+ struct call_single_data csd_stack = { .flags = CSD_FLAG_LOCK | CSD_FLAG_SYNCHRONOUS };
int this_cpu;
int err;
WARN_ON_ONCE(cpu_online(this_cpu) && irqs_disabled()
&& !oops_in_progress);
- err = generic_exec_single(cpu, NULL, func, info, wait);
+ csd = &csd_stack;
+ if (!wait) {
+ csd = this_cpu_ptr(&csd_data);
+ csd_lock(csd);
+ }
+
+ err = generic_exec_single(cpu, csd, func, info);
+
+ if (wait)
+ csd_lock_wait(csd);
put_cpu();
int err = 0;
preempt_disable();
- err = generic_exec_single(cpu, csd, csd->func, csd->info, 0);
+
+ /* We could deadlock if we have to wait here with interrupts disabled! */
+ if (WARN_ON_ONCE(csd->flags & CSD_FLAG_LOCK))
+ csd_lock_wait(csd);
+
+ csd->flags = CSD_FLAG_LOCK;
+ smp_wmb();
+
+ err = generic_exec_single(cpu, csd, csd->func, csd->info);
preempt_enable();
return err;
return;
}
- cfd = &__get_cpu_var(cfd_data);
+ cfd = this_cpu_ptr(&cfd_data);
cpumask_and(cfd->cpumask, mask, cpu_online_mask);
cpumask_clear_cpu(this_cpu, cfd->cpumask);
struct call_single_data *csd = per_cpu_ptr(cfd->csd, cpu);
csd_lock(csd);
+ if (wait)
+ csd->flags |= CSD_FLAG_SYNCHRONOUS;
csd->func = func;
csd->info = info;
llist_add(&csd->llist, &per_cpu(call_single_queue, cpu));
smp_call_function(do_nothing, NULL, 1);
}
EXPORT_SYMBOL_GPL(kick_all_cpus_sync);
+
+/**
+ * wake_up_all_idle_cpus - break all cpus out of idle
+ * wake_up_all_idle_cpus try to break all cpus which is in idle state even
+ * including idle polling cpus, for non-idle cpus, we will do nothing
+ * for them.
+ */
+void wake_up_all_idle_cpus(void)
+{
+ int cpu;
+
+ preempt_disable();
+ for_each_online_cpu(cpu) {
+ if (cpu == smp_processor_id())
+ continue;
+
+ wake_up_if_idle(cpu);
+ }
+ preempt_enable();
+}
+EXPORT_SYMBOL_GPL(wake_up_all_idle_cpus);