static int __try_remote_softirq(struct call_single_data *cp, int cpu, int softirq)
{
if (cpu_online(cpu)) {
cp->func = remote_softirq_receive;
cp->info = &softirq;
cp->flags = 0;
__smp_call_function_single(cpu, cp, 0);
return 0;
}
return 1;
}
/*
* Setup and invoke a run of 'trigger_softirq' on the given cpu.
*/
static int raise_blk_irq(int cpu, struct request *rq)
{
if (cpu_online(cpu)) {
struct call_single_data *data = &rq->csd;
data->func = trigger_softirq;
data->info = rq;
data->flags = 0;
__smp_call_function_single(cpu, data, 0);
return 0;
}
return 1;
}
static void update_timers(int cpu)
{
struct call_single_data data = {.func = restart_watchdog_hrtimer};
/*
* Make sure that perf event counter will adopt to a new
* sampling period. Updating the sampling period directly would
* be much nicer but we do not have an API for that now so
* let's use a big hammer.
* Hrtimer will adopt the new period on the next tick but this
* might be late already so we have to restart the timer as well.
*/
watchdog_nmi_disable(cpu);
__smp_call_function_single(cpu, &data, 1);
watchdog_nmi_enable(cpu);
}
static void null_cmd_end_ipi(struct nullb_cmd *cmd)
{
struct call_single_data *data = &cmd->csd;
int cpu = get_cpu();
struct completion_queue *cq = &per_cpu(completion_queues, cpu);
cmd->ll_list.next = NULL;
if (llist_add(&cmd->ll_list, &cq->list)) {
data->func = null_ipi_cmd_end_io;
data->flags = 0;
__smp_call_function_single(cpu, data, 0);
}
put_cpu();
}
int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
int nonatomic, int wait)
{
/* prevent preemption and reschedule on another processor */
unsigned long flags;
int me = get_cpu();
if (cpu == me) {
local_irq_save(flags);
func(info);
local_irq_restore(flags);
} else {
spin_lock_bh(&call_lock);
__smp_call_function_single(cpu, func, info, nonatomic, wait);
spin_unlock_bh(&call_lock);
}
put_cpu();
return 0;
}
int smp_call_function_single(int cpu, void (*func) (void *info), void *info,
int nonatomic, int wait)
{
/* prevent preemption and reschedule on another processor */
int me = get_cpu();
if (cpu == me) {
WARN_ON(1);
put_cpu();
return -EBUSY;
}
/* Can deadlock when called with interrupts disabled */
WARN_ON(irqs_disabled());
spin_lock_bh(&call_lock);
__smp_call_function_single(cpu, func, info, nonatomic, wait);
spin_unlock_bh(&call_lock);
put_cpu();
return 0;
}
