smp_call_function_single

/**
 * smp_call_function_single_async(): Run an asynchronous function on a
 *                   specific CPU.
 * @cpu: The CPU to run on.
 * @csd: Pre-allocated and setup data structure
 *
 * Like smp_call_function_single(), but the call is asynchonous and
 * can thus be done from contexts with disabled interrupts.
 *
 * The caller passes his own pre-allocated data structure
 * (ie: embedded in an object) and is responsible for synchronizing it
 * such that the IPIs performed on the @csd are strictly serialized.
 *
 * NOTE: Be careful, there is unfortunately no current debugging facility to
 * validate the correctness of this serialization.
 */
int smp_call_function_single_async(int cpu, call_single_data_t *csd)
{
    int err = 0;
 
    preempt_disable();
 
    /* 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;
}
函数源码
