/* Implementation  of Linklist in Kernel */
 
 # include <linux/init.h>
 # include <linux/module.h>
 # include <linux/list.h>
 # include <linux/ipc.h>
 # include <linux/shm.h>
 
typedef struct key_map {
      struct list_head list;
      int key;
      unsigned long long global_id;
} key_map;
 
int i=0;
key_map *ptr = NULL;

/** here i have declared it as extern and then assigned them in ll_init */
extern unsigned long long (*ptr1)(int);
extern void (*ptr2)(int, unsigned long long);
/*--------------------------------------------------------------------- */


 void start(void)
 {
    ptr=(key_map *)kmalloc(sizeof(key_map),GFP_KERNEL);
    ptr->key = 0;
    ptr->global_id = 0;
    INIT_LIST_HEAD(&ptr->list);
  } 
    
 
  void addk(int key, unsigned long long global_id) {   
    	key_map *temp = NULL;
        temp = (key_map *)kmalloc(sizeof(key_map),GFP_KERNEL);  
        temp->key = key;  
	temp->global_id = global_id;
	list_add(&temp->list,&ptr->list);
	printk(KERN_ALERT "\n Inserted a value : %d -> %lli ",temp->key,temp->global_id);
  }    

  unsigned long long findk(int key) {
	key_map *temp = NULL;
	int i=0;
	printk(KERN_ALERT "\nwhat is the value of key(findk)::%d",key);
	for (temp=(key_map *)ptr->list.next;temp!=ptr;temp=(key_map *)temp->list.next) {
 		printk(KERN_ALERT "\n%d -> %lli(findk)",temp->key,temp->global_id);
		if(temp->key == key) {
			i++;
			return(temp->global_id);
		}
        
       	}   
	printk(KERN_ALERT "\nhow many times i went in da loop %d\n",i);
	return 0;
 
  } 
 
static int ll_init(void) {
 	printk(KERN_ALERT "\nLL entered !!!");
	start();
	ptr1 = findk;
	ptr2 = addk;
	return 0;
 }
  
 static void ll_exit(void) {
   printk(KERN_ALERT "\nLL exited  !!!");
}

module_init(ll_init);
module_exit(ll_exit);