在此之前,已经对Linux内核链表已经移植过一次。不过是针对Windows平台,下面是链接:https://blog.csdn.net/qq_36883460/article/details/105330799
链表是非常重要的数据结构,针对不同的情况使用不同数据结构,去解决不同的问题。它的优点:动态删除数据单元,不需要移动元素,存储空间可以不连续(与数组相比)。
1、开发环境
使用的开发板:正点原子开发板战舰V3
单片机型号:STM32F103ZET6
开发软件平台:Keil 5
下载linux内核版本:4.19.144 大小:98.64MB
内核代码查看使用软件:Source Insight 4.0
2、移植
由于Keil 5编译从/linux-4.19.144/include/list.h直接复制过来代码有些问题需要修改,要从这些定义头文件里面复制相关代码出来,并加以修改。。
list.h文件里面定义了几个头文件,清除这几个文件的依赖,如下文件:
#include
#include
#include
#include
#include
【1】在这个工程文件里面,按照红色框里面添加 --gnu 在这里提前写这个,大量减少了报错
【2】先在types.h,存放了结构体拷贝下来,放到移植的头文件。
struct list_head {
struct list_head* next, * prev;
};
【3】在Keil5平台上,new会成为关键字,new修改成newStruct,保留typeof()代码不改。
【4】删除了预编译定义 #ifdef CONFIG_DEBUG_LIST与 #else 里面相关代码,只保留了 #else 与 #endif 里面代码。
【5】bool 类型使用可能会出现报错,我查找了uVision Help相关文件,使用这个类型要定义头文件
//bool类型会报错,定义这个头文件才行,我的移植添加了这个
#include
【6】未定义NULL、LIST_POISON1、LIST_POISON2 ,找了相关的代码发现这样定义比较好一点
#define NULL 0
#define LIST_POISON1 NULL
#define LIST_POISON2 NULL
【7】inline属于C++关键字,这里注释掉这个关键字,一般Ctrl+F换出窗口选择Replace进行替换
inline 替换成 /* inline */
【8】在linux内核文件找到相关定义并修改如下,
#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER)
#define container_of(ptr, type, member) \
(type *)( (char *)(ptr) - offsetof(type,member))
其中**container_of()**是通过 成员变量地址 经过计算偏移后 找到 父地址,然后就可以通过指针访问,找到结构体里面其他的变量成员,这个比较美妙了。换句话说,将这个list_head添加到自己的代码里面就能用了。
3、移植后的代码
//代码移植日期:2020/4/8
//代码移植者:须须草
#ifndef _LINUX_LIST_H
#define _LINUX_LIST_H
//bool类型定义,引用的头文件
#include
//结构体文件路径/linux/types.h定义
struct list_head {
struct list_head* next, * prev;
};
struct hlist_head {
struct hlist_node* first;
};
struct hlist_node {
struct hlist_node* next, ** pprev;
};
// 文件路径/tool/virtio/linux/compiler.h
//这里报错添加--gnu -O1 -g -W
#define WRITE_ONCE(var, val) (*((volatile typeof(var)*)(&(var))) = (val))
#define READ_ONCE(var) (*((volatile typeof(var) *)(&(var))))
//手动定义NULL
#define NULL 0
//去除C++编译器预指令
/*#ifdef __cplusplus*/
#define LIST_POISON1 NULL
#define LIST_POISON2 NULL
/*#endif */
/*
* 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.
*/
#define LIST_HEAD_INIT(name) { &(name), &(name) }
#define LIST_HEAD(name) \
struct list_head name = LIST_HEAD_INIT(name)
static /* inline */void INIT_LIST_HEAD(struct list_head* list)
{
WRITE_ONCE(list->next, list);
list->prev = list;
}
static /* inline */bool __list_add_valid(struct list_head* newStruct,
struct list_head* prev,
struct list_head* next)
{
return true;
}
static /* inline */bool __list_del_entry_valid(struct list_head* entry)
{
return true;
}
/*
* 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* newStruct,
struct list_head* prev,
struct list_head* next)
{
if (!__list_add_valid(newStruct, prev, next))
return;
next->prev = newStruct;
newStruct->next = next;
newStruct->prev = prev;
WRITE_ONCE(prev->next, newStruct);
}
/**
* list_add - add a newStruct entry
* @newStruct: 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.
*/
static /* inline */void list_add(struct list_head* newStruct, struct list_head* head)
{
__list_add(newStruct, head, head->next);
}
/**
* list_add_tail - add a newStruct entry
* @newStruct: 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.
*/
static /* inline */void list_add_tail(struct list_head* newStruct, struct list_head* head)
{
__list_add(newStruct, 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;
WRITE_ONCE(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.
*/
static /* inline */void __list_del_entry(struct list_head* entry)
{
if (!__list_del_entry_valid(entry))
return;
__list_del(entry->prev, entry->next);
}
static /* inline */void list_del(struct list_head* entry)
{
__list_del_entry(entry);
entry->next = LIST_POISON1;
entry->prev = LIST_POISON2;
}
/**
* list_replace - replace old entry by new one
* @old : the element to be replaced
* @newStruct : the new element to insert
*
* If @old was empty, it will be overwritten.
*/
static /* inline */void list_replace(struct list_head* old,
struct list_head* newStruct)
{
newStruct->next = old->next;
newStruct->next->prev = newStruct;
newStruct->prev = old->prev;
newStruct->prev->next = newStruct;
}
static /* inline */void list_replace_init(struct list_head* old,
struct list_head* newStruct)
{
list_replace(old, newStruct);
INIT_LIST_HEAD(old);
}
/**
* 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(entry);
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
*/
static /* inline */void list_move(struct list_head* list, struct list_head* head)
{
__list_del_entry(list);
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
*/
static /* inline */void list_move_tail(struct list_head* list,
struct list_head* head)
{
__list_del_entry(list);
list_add_tail(list, head);
}
/**
* list_is_last - tests whether @list is the last entry in list @head
* @list: the entry to test
* @head: the head of the list
*/
static /* inline */int list_is_last(const struct list_head* list,
const struct list_head* head)
{
return list->next == head;
}
/**
* list_empty - tests whether a list is empty
* @head: the list to test.
*/
static /* inline */int list_empty(const struct list_head* head)
{
return READ_ONCE(head->next) == head;
}
/**
* list_empty_careful - tests whether a list is empty and not being modified
* @head: the list to test
*
* Description:
* tests whether a list is empty _and_ checks that no other CPU might be
* in the process of modifying either member (next or prev)
*
* NOTE: using list_empty_careful() without synchronization
* can only be safe if the only activity that can happen
* to the list entry is list_del_init(). Eg. it cannot be used
* if another CPU could re-list_add() it.
*/
static /* inline */int list_empty_careful(const struct list_head* head)
{
struct list_head* next = head->next;
return (next == head) && (next == head->prev);
}
/**
* list_rotate_left - rotate the list to the left
* @head: the head of the list
*/
static /* inline */void list_rotate_left(struct list_head* head)
{
struct list_head* first;
if (!list_empty(head)) {
first = head->next;
list_move_tail(first, head);
}
}
/**
* list_is_singular - tests whether a list has just one entry.
* @head: the list to test.
*/
static /* inline */int list_is_singular(const struct list_head* head)
{
return !list_empty(head) && (head->next == head->prev);
}
static /* inline */void __list_cut_position(struct list_head* list,
struct list_head* head, struct list_head* entry)
{
struct list_head* new_first = entry->next;
list->next = head->next;
list->next->prev = list;
list->prev = entry;
entry->next = list;
head->next = new_first;
new_first->prev = head;
}
/**
* list_cut_position - cut a list into two
* @list: a new list to add all removed entries
* @head: a list with entries
* @entry: an entry within head, could be the head itself
* and if so we won't cut the list
*
* This helper moves the initial part of @head, up to and
* including @entry, from @head to @list. You should
* pass on @entry an element you know is on @head. @list
* should be an empty list or a list you do not care about
* losing its data.
*
*/
static /* inline */void list_cut_position(struct list_head* list,
struct list_head* head, struct list_head* entry)
{
if (list_empty(head))
return;
if (list_is_singular(head) &&
(head->next != entry && head != entry))
return;
if (entry == head)
INIT_LIST_HEAD(list);
else
__list_cut_position(list, head, entry);
}
static /* inline */void __list_splice(const struct list_head* list,
struct list_head* prev,
struct list_head* next)
{
struct list_head* first = list->next;
struct list_head* last = list->prev;
first->prev = prev;
prev->next = first;
last->next = next;
next->prev = last;
}
/**
* list_splice - join two lists, this is designed for stacks
* @list: the new list to add.
* @head: the place to add it in the first list.
*/
static /* inline */void list_splice(const struct list_head* list,
struct list_head* head)
{
if (!list_empty(list))
__list_splice(list, head, head->next);
}
/**
* list_splice_tail - join two lists, each list being a queue
* @list: the new list to add.
* @head: the place to add it in the first list.
*/
static /* inline */void list_splice_tail(struct list_head* list,
struct list_head* head)
{
if (!list_empty(list))
__list_splice(list, head->prev, 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, head->next);
INIT_LIST_HEAD(list);
}
}
/**
* list_splice_tail_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.
*
* Each of the lists is a queue.
* The list at @list is reinitialised
*/
static /* inline */void list_splice_tail_init(struct list_head* list,
struct list_head* head)
{
if (!list_empty(list)) {
__list_splice(list, head->prev, head);
INIT_LIST_HEAD(list);
}
}
//ÓÉÓÚûÓÐoffsetofºê¶¨Ò壬Õâ¸öÎÒÐèÒªÖØÐÂÌí¼Ó¡£¡£¡£
#define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER)
#define container_of(ptr, type, member) (type *)((char *) (ptr) - offsetof(type,member))
/**
* 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_head within the struct.
*/
#define list_entry(ptr, type, member) \
container_of(ptr, type, member)
/**
* list_first_entry - get the first element from a list
* @ptr: the list head to take the element from.
* @type: the type of the struct this is embedded in.
* @member: the name of the list_head within the struct.
*
* Note, that list is expected to be not empty.
*/
#define list_first_entry(ptr, type, member) \
list_entry((ptr)->next, type, member)
/**
* list_last_entry - get the last element from a list
* @ptr: the list head to take the element from.
* @type: the type of the struct this is embedded in.
* @member: the name of the list_head within the struct.
*
* Note, that list is expected to be not empty.
*/
#define list_last_entry(ptr, type, member) \
list_entry((ptr)->prev, type, member)
/**
* list_first_entry_or_null - get the first element from a list
* @ptr: the list head to take the element from.
* @type: the type of the struct this is embedded in.
* @member: the name of the list_head within the struct.
*
* Note that if the list is empty, it returns NULL.
*/
#define list_first_entry_or_null(ptr, type, member) ({ \
struct list_head *head__ = (ptr); \
struct list_head *pos__ = READ_ONCE(head__->next); \
pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
})
/**
* list_next_entry - get the next element in list
* @pos: the type * to cursor
* @member: the name of the list_head within the struct.
*/
#define list_next_entry(pos, member) \
list_entry((pos)->member.next, typeof(*(pos)), member)
/**
* list_prev_entry - get the prev element in list
* @pos: the type * to cursor
* @member: the name of the list_head within the struct.
*/
#define list_prev_entry(pos, member) \
list_entry((pos)->member.prev, typeof(*(pos)), member)
/**
* list_for_each - iterate over a list
* @pos: the &struct list_head to use as a loop cursor.
* @head: the head for your list.
*/
#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 cursor.
* @head: the head for your list.
*/
#define list_for_each_prev(pos, head) \
for (pos = (head)->prev; pos != (head); pos = pos->prev)
/**
* list_for_each_safe - iterate over a list safe against removal of list entry
* @pos: the &struct list_head to use as a loop cursor.
* @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_prev_safe - iterate over a list backwards safe against removal of list entry
* @pos: the &struct list_head to use as a loop cursor.
* @n: another &struct list_head to use as temporary storage
* @head: the head for your list.
*/
#define list_for_each_prev_safe(pos, n, head) \
for (pos = (head)->prev, n = pos->prev; \
pos != (head); \
pos = n, n = pos->prev)
/**
* list_for_each_entry - iterate over list of given type
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the list_head within the struct.
*/
#define list_for_each_entry(pos, head, member) \
for (pos = list_first_entry(head, typeof(*pos), member); \
&pos->member != (head); \
pos = list_next_entry(pos, member))
/**
* list_for_each_entry_reverse - iterate backwards over list of given type.
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the list_head within the struct.
*/
#define list_for_each_entry_reverse(pos, head, member) \
for (pos = list_last_entry(head, typeof(*pos), member); \
&pos->member != (head); \
pos = list_prev_entry(pos, member))
/**
* list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue()
* @pos: the type * to use as a start point
* @head: the head of the list
* @member: the name of the list_head within the struct.
*
* Prepares a pos entry for use as a start point in list_for_each_entry_continue().
*/
#define list_prepare_entry(pos, head, member) \
((pos) ? : list_entry(head, typeof(*pos), member))
/**
* list_for_each_entry_continue - continue iteration over list of given type
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the list_head within the struct.
*
* Continue to iterate over list of given type, continuing after
* the current position.
*/
#define list_for_each_entry_continue(pos, head, member) \
for (pos = list_next_entry(pos, member); \
&pos->member != (head); \
pos = list_next_entry(pos, member))
/**
* list_for_each_entry_continue_reverse - iterate backwards from the given point
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the list_head within the struct.
*
* Start to iterate over list of given type backwards, continuing after
* the current position.
*/
#define list_for_each_entry_continue_reverse(pos, head, member) \
for (pos = list_prev_entry(pos, member); \
&pos->member != (head); \
pos = list_prev_entry(pos, member))
/**
* list_for_each_entry_from - iterate over list of given type from the current point
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the list_head within the struct.
*
* Iterate over list of given type, continuing from current position.
*/
#define list_for_each_entry_from(pos, head, member) \
for (; &pos->member != (head); \
pos = list_next_entry(pos, member))
/**
* list_for_each_entry_from_reverse - iterate backwards over list of given type
* from the current point
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the list_head within the struct.
*
* Iterate backwards over list of given type, continuing from current position.
*/
#define list_for_each_entry_from_reverse(pos, head, member) \
for (; &pos->member != (head); \
pos = list_prev_entry(pos, member))
/**
* 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 cursor.
* @n: another type * to use as temporary storage
* @head: the head for your list.
* @member: the name of the list_head within the struct.
*/
#define list_for_each_entry_safe(pos, n, head, member) \
for (pos = list_first_entry(head, typeof(*pos), member), \
n = list_next_entry(pos, member); \
&pos->member != (head); \
pos = n, n = list_next_entry(n, member))
/**
* list_for_each_entry_safe_continue - continue list iteration safe against removal
* @pos: the type * to use as a loop cursor.
* @n: another type * to use as temporary storage
* @head: the head for your list.
* @member: the name of the list_head within the struct.
*
* Iterate over list of given type, continuing after current point,
* safe against removal of list entry.
*/
#define list_for_each_entry_safe_continue(pos, n, head, member) \
for (pos = list_next_entry(pos, member), \
n = list_next_entry(pos, member); \
&pos->member != (head); \
pos = n, n = list_next_entry(n, member))
/**
* list_for_each_entry_safe_from - iterate over list from current point safe against removal
* @pos: the type * to use as a loop cursor.
* @n: another type * to use as temporary storage
* @head: the head for your list.
* @member: the name of the list_head within the struct.
*
* Iterate over list of given type from current point, safe against
* removal of list entry.
*/
#define list_for_each_entry_safe_from(pos, n, head, member) \
for (n = list_next_entry(pos, member); \
&pos->member != (head); \
pos = n, n = list_next_entry(n, member))
/**
* list_for_each_entry_safe_reverse - iterate backwards over list safe against removal
* @pos: the type * to use as a loop cursor.
* @n: another type * to use as temporary storage
* @head: the head for your list.
* @member: the name of the list_head within the struct.
*
* Iterate backwards over list of given type, safe against removal
* of list entry.
*/
#define list_for_each_entry_safe_reverse(pos, n, head, member) \
for (pos = list_last_entry(head, typeof(*pos), member), \
n = list_prev_entry(pos, member); \
&pos->member != (head); \
pos = n, n = list_prev_entry(n, member))
/**
* list_safe_reset_next - reset a stale list_for_each_entry_safe loop
* @pos: the loop cursor used in the list_for_each_entry_safe loop
* @n: temporary storage used in list_for_each_entry_safe
* @member: the name of the list_head within the struct.
*
* list_safe_reset_next is not safe to use in general if the list may be
* modified concurrently (eg. the lock is dropped in the loop body). An
* exception to this is if the cursor element (pos) is pinned in the list,
* and list_safe_reset_next is called after re-taking the lock and before
* completing the current iteration of the loop body.
*/
#define list_safe_reset_next(pos, n, member) \
n = list_next_entry(pos, member)
/*
* Double linked lists with a single pointer list head.
* Mostly useful for hash tables where the two pointer list head is
* too wasteful.
* You lose the ability to access the tail in O(1).
*/
#define HLIST_HEAD_INIT { .first = NULL }
#define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
static /* inline */void INIT_HLIST_NODE(struct hlist_node* h)
{
h->next = NULL;
h->pprev = NULL;
}
static /* inline */int hlist_unhashed(const struct hlist_node* h)
{
return !h->pprev;
}
static /* inline */int hlist_empty(const struct hlist_head* h)
{
return !READ_ONCE(h->first);
}
static /* inline */void __hlist_del(struct hlist_node* n)
{
struct hlist_node* next = n->next;
struct hlist_node** pprev = n->pprev;
WRITE_ONCE(*pprev, next);
if (next)
next->pprev = pprev;
}
static /* inline */void hlist_del(struct hlist_node* n)
{
__hlist_del(n);
n->next = LIST_POISON1;
n->pprev = LIST_POISON2;
}
static /* inline */void hlist_del_init(struct hlist_node* n)
{
if (!hlist_unhashed(n)) {
__hlist_del(n);
INIT_HLIST_NODE(n);
}
}
static /* inline */void hlist_add_head(struct hlist_node* n, struct hlist_head* h)
{
struct hlist_node* first = h->first;
n->next = first;
if (first)
first->pprev = &n->next;
WRITE_ONCE(h->first, n);
n->pprev = &h->first;
}
/* next must be != NULL */
static /* inline */void hlist_add_before(struct hlist_node* n,
struct hlist_node* next)
{
n->pprev = next->pprev;
n->next = next;
next->pprev = &n->next;
WRITE_ONCE(*(n->pprev), n);
}
static /* inline */void hlist_add_behind(struct hlist_node* n,
struct hlist_node* prev)
{
n->next = prev->next;
WRITE_ONCE(prev->next, n);
n->pprev = &prev->next;
if (n->next)
n->next->pprev = &n->next;
}
/* after that we'll appear to be on some hlist and hlist_del will work */
static /* inline */void hlist_add_fake(struct hlist_node* n)
{
n->pprev = &n->next;
}
static /* inline */bool hlist_fake(struct hlist_node* h)
{
return h->pprev == &h->next;
}
/*
* Check whether the node is the only node of the head without
* accessing head:
*/
static /* inline */bool hlist_is_singular_node(struct hlist_node* n, struct hlist_head* h)
{
return !n->next && n->pprev == &h->first;
}
/*
* Move a list from one list head to another. Fixup the pprev
* reference of the first entry if it exists.
*/
static /* inline */void hlist_move_list(struct hlist_head* old,
struct hlist_head* newStruct)
{
newStruct->first = old->first;
if (newStruct->first)
newStruct->first->pprev = &newStruct->first;
old->first = NULL;
}
#define hlist_entry(ptr, type, member) container_of(ptr,type,member)
#define hlist_for_each(pos, head) \
for (pos = (head)->first; pos ; pos = pos->next)
#define hlist_for_each_safe(pos, n, head) \
for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
pos = n)
#define hlist_entry_safe(ptr, type, member) \
({ typeof(ptr) ____ptr = (ptr); \
____ptr ? hlist_entry(____ptr, type, member) : NULL; \
})
/**
* hlist_for_each_entry - iterate over list of given type
* @pos: the type * to use as a loop cursor.
* @head: the head for your list.
* @member: the name of the hlist_node within the struct.
*/
#define hlist_for_each_entry(pos, head, member) \
for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\
pos; \
pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
/**
* hlist_for_each_entry_continue - iterate over a hlist continuing after current point
* @pos: the type * to use as a loop cursor.
* @member: the name of the hlist_node within the struct.
*/
#define hlist_for_each_entry_continue(pos, member) \
for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\
pos; \
pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
/**
* hlist_for_each_entry_from - iterate over a hlist continuing from current point
* @pos: the type * to use as a loop cursor.
* @member: the name of the hlist_node within the struct.
*/
#define hlist_for_each_entry_from(pos, member) \
for (; pos; \
pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
/**
* hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
* @pos: the type * to use as a loop cursor.
* @n: another &struct hlist_node to use as temporary storage
* @head: the head for your list.
* @member: the name of the hlist_node within the struct.
*/
#define hlist_for_each_entry_safe(pos, n, head, member) \
for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\
pos && ({ n = pos->member.next; 1; }); \
pos = hlist_entry_safe(n, typeof(*pos), member))
#endif
5、主函数应用代码
#include "sys.h"
#include "usart.h"
#include "delay.h"
#include "list.h"
struct student{
char name[60];
int id;
struct list_head list;
};
int main(void)
{
struct student *q;
struct student *p;
struct student A = { "张三" ,13, LIST_HEAD_INIT(A.list) };
struct student B = { "小红" ,22, LIST_HEAD_INIT(B.list) };
struct student C = { "李四" ,34, LIST_HEAD_INIT(C.list) };
list_add_tail(&B.list, &A.list);//B成员添加到A列队尾部
list_add_tail(&C.list, &A.list);//C成员添加到A列队尾部
Stm32_Clock_Init(9); //8MHz晶振,8*9=72Mhz系统时钟
uart_init(72,115200); //72MHz系统时钟,波特率115200
delay_init(72); //72MHz系统时钟
while(1)
{
q = container_of(&A.list, struct student , list);
p = container_of(q->list.next, struct student , list);
printf("---------------------------------");
printf("name: %d ",p->id);
printf("name: %s ",p->name);
printf("---------------------------------");
p = container_of(q->list.next->next, struct student, list);
printf("---------------------------------");
printf("name: %d ",p->id);
printf("name: %s ",p->name);
printf("---------------------------------");
p = container_of(q->list.next->next->next, struct student, list);
printf("---------------------------------");
printf("id: %d ",p->id);
printf("name: %s ",p->name);
printf("---------------------------------");
delay_ms(2000); //ÑÓʱ2Ãë
}
}
程序下载烧录,通过串口助手观察;
这个结果说明代码移植成功,而且编译后占用空间不大。
总结:利用linux内核链表移植到STM32非常便利,而且链表在数据结构中栈重要地位。
更新中。。。