#include <asm/system.h>
#if defined(CONFIG_STOP_MACHINE) && defined(CONFIG_SMP)
+
+#define ALL_CPUS ~0U
+
/**
* stop_machine_run: freeze the machine on all CPUs and run this function
* @fn: the function to run
* @data: the data ptr for the @fn()
- * @cpu: the cpu to run @fn() on (or any, if @cpu == NR_CPUS.
+ * @cpu: if @cpu == n, run @fn() on cpu n
+ * if @cpu == NR_CPUS, run @fn() on any cpu
+ * if @cpu == ALL_CPUS, run @fn() first on the calling cpu, and then
+ * concurrently on all the other cpus
*
* Description: This causes a thread to be scheduled on every other cpu,
* each of which disables interrupts, and finally interrupts are disabled
STOPMACHINE_WAIT,
STOPMACHINE_PREPARE,
STOPMACHINE_DISABLE_IRQ,
+ STOPMACHINE_RUN,
STOPMACHINE_EXIT,
};
+struct stop_machine_data {
+ int (*fn)(void *);
+ void *data;
+ struct completion done;
+ int run_all;
+} smdata;
+
static enum stopmachine_state stopmachine_state;
static unsigned int stopmachine_num_threads;
static atomic_t stopmachine_thread_ack;
{
int irqs_disabled = 0;
int prepared = 0;
+ int ran = 0;
cpumask_of_cpu_ptr(cpumask, (int)(long)cpu);
set_cpus_allowed_ptr(current, cpumask);
prepared = 1;
smp_mb(); /* Must read state first. */
atomic_inc(&stopmachine_thread_ack);
+ } else if (stopmachine_state == STOPMACHINE_RUN && !ran) {
+ smdata.fn(smdata.data);
+ ran = 1;
+ smp_mb(); /* Must read state first. */
+ atomic_inc(&stopmachine_thread_ack);
}
/* Yield in first stage: migration threads need to
* help our sisters onto their CPUs. */
preempt_enable_no_resched();
}
-struct stop_machine_data {
- int (*fn)(void *);
- void *data;
- struct completion done;
-};
+static void run_other_cpus(void)
+{
+ stopmachine_set_state(STOPMACHINE_RUN);
+}
static int do_stop(void *_smdata)
{
ret = stop_machine();
if (ret == 0) {
ret = smdata->fn(smdata->data);
+ if (smdata->run_all)
+ run_other_cpus();
restart_machine();
}
struct stop_machine_data smdata;
struct task_struct *p;
+ mutex_lock(&stopmachine_mutex);
+
smdata.fn = fn;
smdata.data = data;
+ smdata.run_all = (cpu == ALL_CPUS) ? 1 : 0;
init_completion(&smdata.done);
- mutex_lock(&stopmachine_mutex);
+ smp_wmb(); /* make sure other cpus see smdata updates */
/* If they don't care which CPU fn runs on, bind to any online one. */
- if (cpu == NR_CPUS)
+ if (cpu == NR_CPUS || cpu == ALL_CPUS)
cpu = raw_smp_processor_id();
p = kthread_create(do_stop, &smdata, "kstopmachine");