#include<linux/module.h>
#include<linux/random.h>
#include<linux/kfifo.h>

#define NUMBER_OF_ELEMENTS 2

static char* foo = "Pierwszy ciag znakowy";
module_param(foo,charp,0644);
MODULE_PARM_DESC(foo,"ciag pierwszy");
static char* foo2 = "drugi ciag znakowy";
module_param(foo2,charp,0644);
MODULE_PARM_DESC(foo2,"ciag drugi");

static struct kfifo fifo_queue;

static int __init fifomod_init(void)
{
	int returned_value;
	unsigned int returned_size;
	char buff[20];
	int fifo_size = sizeof(foo)+sizeof(foo2);

	returned_value = kfifo_alloc(&fifo_queue,fifo_size,GFP_KERNEL);
	if(returned_value) {
		pr_alert("Error allocating kfifo!\n");
		return -ENOMEM;
	}
	while(!kfifo_is_full(&fifo_queue)) {
		returned_size = kfifo_in(&fifo_queue,foo,sizeof(foo));
		if(returned_size!=sizeof(foo))
			pr_alert("Enqueue error 1\n");

			returned_size = kfifo_in(&fifo_queue,foo2,sizeof(foo2));
		if(returned_size!=sizeof(foo2))
			pr_alert("Enqueue error 2\n");
	}
	returned_size = kfifo_out_peek(&fifo_queue,buff,sizeof(buff));
	if(returned_size!=sizeof(buff))
		pr_alert("Error peeking element form the queue!\n");
	pr_notice("Value in the queue: %u\n",buff);

	return 0;
}

static void __exit fifomod_exit(void)
{
	int returned_size;
	char buff[20];

	while(!kfifo_is_empty(&fifo_queue)) {
		returned_size = kfifo_out(&fifo_queue,buff,sizeof(buff));
		if(returned_size!=sizeof(buff))
			pr_alert("Dequeue error!\n");
		pr_notice("Value from the queue: %u\n",buff);
	}

	kfifo_free(&fifo_queue);
}

module_init(fifomod_init);
module_exit(fifomod_exit);

MODULE_AUTHOR("Arkadiusz Chrobot <a.chrobot@tu.kielce.pl>");
MODULE_LICENSE("GPL");
MODULE_DESCRIPTION("An exemplary module demonstrating the usage of a kernel FIFO queue.");
MODULE_VERSION("1.0");