我很难使用 Linux 内核中的 list.h 为我的代码提供链表功能。我怀疑我几乎有功能代码，但我在某处混淆了指针。
如何正确使用 list_for_each 宏？在我的代码中，它陷入了无限循环并且没有退出列表。下面是我的代码片段中的问题所在（查看 add_kv 函数）：
dict_entry *alloc_dict(void)
{
//allocates the linked list head node
dict_entry *d = malloc(sizeof(dict_entry));
INIT_LIST_HEAD(&d->list);
return d;
}
void free_dict(dict_entry *d)
{
//TODO: free each dict_entry struct and their keys and values.
free(d);
}
int add_kv(dict_entry *d, char *key, char *value)
{
if(!key || !d) return 0; //if key or d is null, return 0
struct list_head *p; //serves as the cursor
dict_entry *entry; //empty dict_entry
entry = alloc_dict(); //allocate memory for it
list_for_each(p, &d->list){
d = list_entry(p, dict_entry, list); //CHANGED TO d FROM entry
printf("gothere, p = %p\n",p); // something in here is creating an infinite loop. p is moving back and forth. this is the big problem in this code
if(strcmp(entry->key, key) == 0){
free(entry->value);
entry->value = 0;
entry->value = malloc(strlen(value));
strcpy(entry->value, value);
return 1; //how do i get rid of entry?
}
}
//If you haven't returned by now, continue on to add a new entry at the end of the list
entry->key = malloc(strlen(key)); //allocate memory for the key
strcpy(entry->key, key); //copy the key value to the key in the entry
entry->value = malloc(strlen(value)); //allocate memory for value
strcpy(entry->value, value); //copy value value to the value in the entry
list_add(&entry->list,&d->list); //tacks the list of the new entry onto the existing list (provided as d)
return 1;
}
下面是 list.h 中的 list_for_each 宏，供参考：
/**
* 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)
这里是 list.h 中的 list_entry 宏，也供参考：
/**
* 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.
*/
#define list_entry(ptr, type, member) \
container_of(ptr, type, member)
...以及我正在使用的 dict_entry 结构：
6 typedef struct {
7 char *key;
8 char *value;
9 struct list_head list;
10 }dict_entry;
...运行时，会发生这种情况：
gothere, p = 0x1178050
gothere, p = 0x1178020
gothere, p = 0x1178050
gothere, p = 0x1178020
一遍又一遍地。
关于如何使用 list.h 实现列表的一个很好的解释可以在这里找到以供参考。