Kernel linked list (general linked list) "list.h" simple version and individual comments

In your own installation linux Enter commands in the hostnamectl
Find kernel version
From the kernel include/linux/ You can copy the header file list.h.
"list.h" Simple version of

#ifndef __DLIST_H
#define __DLIST_H

/* This file is from Linux Kernel (include/linux/list.h) * and modified by simply removing hardware prefetching of list items. * Here by copyright, credits attributed to wherever they belong. * Kulesh Shanmugasundaram (kulesh [squiggly] isis.poly.edu) */

/* * Simple doubly linked list implementation. * * Some of the internal functions (“__xxx”) are useful when * manipulating whole lists rather than single entries, as * sometimes we already know the next/prev entries and we can * generate better code by using them directly rather than * using the generic single-entry routines. */
/** * container_of - cast a member of a structure out to the containing structure * * @ptr: the pointer to the member. * @type: the type of the container struct this is embedded in. * @member: the name of the member within the struct. * */
#define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)

#define container_of(ptr, type, member) ({
       \ const typeof( ((type *)0)->member ) *__mptr = (ptr); \ (type *)( (char *)__mptr - offsetof(type,member) );})
/* * These are non-NULL pointers that will result in page faults * under normal circumstances, used to verify that nobody uses * non-initialized list entries. */
#define LIST_POISON1 ((void *) 0x00100100)
#define LIST_POISON2 ((void *) 0x00200)

//  Kernel standard linked list ： Small structures 
struct list_head {
    
	struct list_head *next;
	struct list_head *prev;
};

#define LIST_HEAD_INIT(name) {
       &(name), &(name) }

#define LIST_HEAD(name) \ struct list_head name = LIST_HEAD_INIT(name)

//  Initialize the small structure , Let itself form a two-way cycle 
#define INIT_LIST_HEAD(ptr) do {
       \ (ptr)->next = (ptr); (ptr)->prev = (ptr); \ } while (0)

/* * Insert a new entry between two known consecutive entries. * * This is only for internal list manipulation where we know * the prev/next entries already! */
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;
}
// middle 4 Always a pointer , The kernel turns all pointer operations of a two-way loop into functions .
// The kernel linked list has absolutely no front and back pointers , All pointer operations are encapsulated into functions 

/** * list_add – add a new entry * @new: new entry to be added * @head: list head to add it after * * Insert a new entry after the specified head. * This is good for implementing stacks. */

//  New nodes new Insert into to head The head of the linked list 
static inline void list_add(struct list_head *new, struct list_head *head)
{
    
	__list_add(new, head, head->next);
}

/** * list_add_tail – add a new entry * @new: new entry to be added * @head: list head to add it before * * Insert a new entry before the specified head. * This is useful for implementing queues. */

//  New nodes new Insert into to head At the end of the linked list headed by 
static inline void list_add_tail(struct list_head *new, struct list_head *head)
{
    
	__list_add(new, head->prev, head);
}

/* * Delete a list entry by making the prev/next entries * point to each other. * * This is only for internal list manipulation where we know * the prev/next entries already! */
static inline void __list_del(struct list_head *prev, struct list_head *next)
{
    

	next->prev = prev;
	prev->next = next;
}

/** * list_del – deletes entry from list. * @entry: the element to delete from the list. * Note: list_empty on entry does not return true after this, the entry is in an undefined state. */

//  take entry Node to , Remove from the linked list 
static inline void list_del(struct list_head *entry)
{
    
	__list_del(entry->prev, entry->next);
	entry->next = (void *) 0;
	entry->prev = (void *) 0;
}

/** * list_del_init – deletes entry from list and reinitialize it. * @entry: the element to delete from the list. */
static inline void list_del_init(struct list_head *entry)
{
    
	__list_del(entry->prev, entry->next);
	INIT_LIST_HEAD(entry);
}

/** * list_move – delete from one list and add as another’s head * @list: the entry to move * @head: the head that will precede our entry */

//  The nodes list Move to head The head of the linked list 
static inline void list_move(struct list_head *list,
				struct list_head *head)
{
    
	__list_del(list->prev, list->next);
	list_add(list, head);
}

/** * list_move_tail – delete from one list and add as another’s tail * @list: the entry to move * @head: the head that will follow our entry */

//  The nodes list Move to head At the end of the linked list headed by 
static inline void list_move_tail(struct list_head *list,
					struct list_head *head)
{
    
	__list_del(list->prev, list->next);
	list_add_tail(list, head);
}

/** * list_empty – tests whether a list is empty * @head: the list to test. */

// Judge whether the list is empty 
static inline int list_empty(struct list_head *head)
{
    
	return head->next == head;
}

static inline void __list_splice(struct list_head *list,
					struct list_head *head)
{
    
	struct list_head *first = list->next;
	struct list_head *last = list->prev;
	struct list_head *at = head->next;

	first->prev = head;
	head->next = first;

	last->next = at;
	at->prev = last;
}

/** * list_splice – join two lists * @list: the new list to add. * @head: the place to add it in the first list. */

// Add a new list to the original list 
static inline void list_splice(struct list_head *list, struct list_head *head)
{
    
if (!list_empty(list))
__list_splice(list, head);
}



/** * list_splice_init – join two lists and reinitialise the emptied list. * @list: the new list to add. * @head: the place to add it in the first list. * * The list at @list is reinitialised */
static inline void list_splice_init(struct list_head *list,
struct list_head *head)
{
    
if (!list_empty(list)) {
    
__list_splice(list, head);
INIT_LIST_HEAD(list);
}
}

/** * list_entry – get the struct for this entry * @ptr: the &struct list_head pointer. * @type: the type of the struct this is embedded in. * @member: the name of the list_struct within the struct. */

//  Small structure pointer ptr Convert to large structure pointer p: p = list_entry(ptr, type, member)
#define list_entry(ptr, type, member) \ ((type *)((char *)(ptr)-(unsigned long)(&((type *)0)->member)))

/** * list_for_each - iterate over a list * @pos: the &struct list_head to use as a loop counter. * @head: the head for your list. */

//  Traverse the linked list from scratch （ During traversal , Nodes cannot be deleted ）
#define list_for_each(pos, head) \ for (pos = (head)->next; pos != (head); \ pos = pos->next)

/** * list_for_each_prev - iterate over a list backwards * @pos: the &struct list_head to use as a loop counter. * @head: the head for your list. */

//  Traverse the linked list from the end 
#define list_for_each_prev(pos, head) \ for (pos = (head)->prev; pos != (head); \ pos = pos->prev)
/** * list_for_each_entry - iterate over list of given type * @pos: the type * to use as a loop counter. * @head: the head for your list. * @member: the name of the list_struct within the struct. */

//  Traverse the linked list from scratch （ During traversal , Nodes can be deleted ）
#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))
/** * list_for_each_safe - iterate over a list safe against removal of list entry * @pos: the &struct list_head to use as a loop counter. * @n: another &struct list_head to use as temporary storage * @head: the head for your list. */
#define list_for_each_safe(pos, n, head) \ for (pos = (head)->next, n = pos->next; pos != (head); \ pos = n, n = pos->next)



/** * list_for_each_entry_safe – iterate over list of given type safe against removal of list entry * @pos: the type * to use as a loop counter. * @n: another type * to use as temporary storage * @head: the head for your list. * @member: the name of the list_struct within the struct. */
#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))

#endif

You can add header files in the future "list.h" Use , You can also write your own kernel linked list （ General linked list ）.