nhmk/examples/completions.c
2021-07-22 06:35:24 +08:00

78 lines
1.7 KiB
C

#include <linux/init.h>
#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/kthread.h>
#include <linux/completion.h>
static struct {
struct completion crank_comp;
struct completion flywheel_comp;
} machine;
static int machine_crank_thread(void* arg)
{
pr_info("Turn the crank\n");
complete_all(&machine.crank_comp);
complete_and_exit(&machine.crank_comp, 0);
}
static int machine_flywheel_spinup_thread(void* arg)
{
wait_for_completion(&machine.crank_comp);
pr_info("Flywheel spins up\n");
complete_all(&machine.flywheel_comp);
complete_and_exit(&machine.flywheel_comp, 0);
}
static int completions_init(void)
{
struct task_struct* crank_thread;
struct task_struct* flywheel_thread;
pr_info("completions example\n");
init_completion(&machine.crank_comp);
init_completion(&machine.flywheel_comp);
crank_thread =
kthread_create(machine_crank_thread,
NULL, "KThread Crank");
if (IS_ERR(crank_thread))
goto ERROR_THREAD_1;
flywheel_thread =
kthread_create(machine_flywheel_spinup_thread,
NULL, "KThread Flywheel");
if (IS_ERR(flywheel_thread))
goto ERROR_THREAD_2;
wake_up_process(flywheel_thread);
wake_up_process(crank_thread);
return 0;
ERROR_THREAD_2:
kthread_stop(crank_thread);
ERROR_THREAD_1:
return -1;
}
void completions_exit(void)
{
wait_for_completion(&machine.crank_comp);
wait_for_completion(&machine.flywheel_comp);
pr_info("completions exit\n");
}
module_init(completions_init);
module_exit(completions_exit);
MODULE_AUTHOR("Bob Mottram");
MODULE_DESCRIPTION("Completions example");
MODULE_LICENSE("GPL");