refcount api test

refcounter_test.c

#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/refcount.h>
#include <linux/smp.h>
#include <linux/slab.h>

MODULE_DESCRIPTION("refcount api test");
MODULE_AUTHOR("masami256");
MODULE_LICENSE("GPL");

static refcount_t counter1 = REFCOUNT_INIT(1);
static refcount_t *counter2;
static int non_atomic_counter;

static void refcounter_test_run(void *info)
{
        pr_info("%s: cpu %d\n", __func__, smp_processor_id());
        refcount_inc(&counter1);
        refcount_inc(counter2);
        non_atomic_counter++;
}

static int refcounter_test_init(void)
{
        pr_info("%s start\n", __func__);

        counter2 = kmalloc(sizeof(refcount_t), GFP_KERNEL);
        if (!counter2)
                return -ENOMEM;

        refcount_set(counter2, 1);

        on_each_cpu(&refcounter_test_run, NULL, 1);
        pr_info("counter1: %d\n", refcount_read(&counter1));
        pr_info("counter2: %d\n", refcount_read(counter2));
        pr_info("non_atomic_counter: %d\n", non_atomic_counter);

        return 0;
}

static void refcounter_test_cleanup(void)
{
        pr_info("%s bye\n", __func__);
        kfree(counter2);
}

module_init(refcounter_test_init);
module_exit(refcounter_test_cleanup);