#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/slab.h>
struct object_list {
int id;
struct list_head list;
};
LIST_HEAD(obj_context);
static int __init
my_init(void)
{
struct object_list *obj;
obj = kmalloc(sizeof(struct object_list), GFP_KERNEL);
obj->id = 5;
list_add(&obj->list, &obj_context);
return (0);
}
static void __exit
my_fini(void)
{
struct list_head *pos, *q;
list_for_each_safe(pos, q, &obj_context) {
struct object_list *obj = NULL;
obj = list_entry(pos, struct object_list, list);
list_del(pos);
kfree(obj);
}
return;
}
module_init(my_init);
module_exit(my_fini);
MODULE_DESCRIPTION("Sample Code");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("Krishna Mohan");
I was an working on porting driver in user space and didn't want to write my own implementation. I copied the code from the kernel and tried in userspace and as expected it worked fine. I'm doing the same for other function which i will keep posting on my blog.
#include <stdio.h>
#include <stdlib.h>
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
struct list_head {
struct list_head *next, *prev;
};
struct nvme_ns {
struct list_head list;
int num;
};
static inline void INIT_LIST_HEAD(struct list_head *list)
{
list->next = list;
list->prev = list;
}
static inline void __list_add(struct list_head *_new,
struct list_head *prev,
struct list_head *next)
{
next->prev = _new;
_new->next = next;
_new->prev = prev;
prev->next = _new;
}
static inline void list_add_tail(struct list_head *_new, struct list_head *head)
{
__list_add(_new, head->prev, head);
}
#define container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type, member) ); })
#define list_entry(ptr, type, member) \
container_of(ptr, type, member)
#define list_for_each_entry(pos, head, member) \
for (pos = list_entry((head)->next, typeof(*pos), member); \
&pos->member != (head); \
pos = list_entry(pos->member.next, typeof(*pos), member))
#define list_for_each_entry_safe(pos, n, head, member) \
for (pos = list_entry((head)->next, typeof(*pos), member), \
n = list_entry(pos->member.next, typeof(*pos), member); \
&pos->member != (head); \
pos = n, n = list_entry(n->member.next, typeof(*n), member))
static inline void __list_del(struct list_head *prev, struct list_head *next)
{
next->prev = prev;
prev->next = next;
}
#define LIST_POISON1 ((void *) 0x00100100)
#define LIST_POISON2 ((void *) 0x00200200)
static inline void list_del(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
entry->next = (struct list_head *) LIST_POISON1;
entry->prev = (struct list_head *) LIST_POISON2;
}
int
main()
{
struct list_head name;
struct nvme_ns *ns, *next;
INIT_LIST_HEAD(&name);
ns = malloc(sizeof(struct nvme_ns));
printf("alloc %p\n", ns);
ns->num = 1;
list_add_tail(&ns->list, &name);
ns = malloc(sizeof(struct nvme_ns));
printf("alloc %p\n", ns);
ns->num = 2;
list_add_tail(&ns->list, &name);
list_for_each_entry(ns, &name, list)
printf("num is %d\n", ns->num);
list_for_each_entry_safe(ns, next, &name, list) {
list_del(&ns->list);
printf("free %p\n", ns);
free(ns);
}
return (0);
}
