Playing with workqueues in the kernel

hellowork.c

#include <linux/init.h>
#include <linux/module.h>
#include <linux/workqueue.h>
#include <linux/proc_fs.h>

/* proc shit */
#define PROCFS_NAME "hellowq"
static struct proc_dir_entry *hellowq_file;
static struct file_operations hellowq_proc_ops;
static char hellowq_buf[1024];

/* wq shit */
static struct workqueue_struct *wq;

static struct job {
	int nsecs;
	struct work_struct work;
} job;

static ssize_t hellowq_read(struct file *fp, char __user *buf, size_t n, loff_t off) {
	pr_info("jobqueue: read called on proc\n");
	return 0;
}

static int hellowq_write(struct file *file, const char *buf, unsigned long n, void *data) {
	pr_info("jobqueue: write called on proc\n");
	return 0;
}

static int __init mod_init(void)
{
	pr_info("jobqueue: init\n");
	wq = alloc_workqueue(PROCFS_NAME, WQ_UNBOUND | WQ_FREEZABLE, WQ_DFL_ACTIVE);
	if (!wq) {
		pr_info("jobqueue: failed to allocate workqueue");
        	return -1;
	}

	hellowq_proc_ops.read = hellowq_read;
	hellowq_file = proc_create_data(PROCFS_NAME, 0666, NULL, &hellowq_proc_ops, NULL);
	if (!hellowq_file) {
		pr_info("jobqueue: failed to create proc entry");
		destroy_workqueue(wq);
        	return -ENOMEM;
	}

	hellowq_file->data = hellowq_buf;
	hellowq_file->read_proc = hellowq_read;
	hellowq_file->write_proc = hellowq_write;

	pr_info("jobqueue: loaded\n");

	return 0;
}

static void __exit mod_exit(void)
{
	remove_proc_entry(PROCFS_NAME, &proc_root);
	destroy_workqueue(wq);
	pr_info("jobqueue: exit\n");
}

module_init(mod_init);
module_exit(mod_exit);
MODULE_LICENSE("GPL v2");