List_head用法

 

1、             LIST_HEAD_INIT是宏，INIT_LIST_HEAD是函数

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

#define LIST_HEAD(name) /

struct list_head name = LIST_HEAD_INIT(name)

//在list前，增加一个Node:item

static inline void list_add_tail(struct list_node *list, struct list_node *item)

//删除Node:item

static inline void list_delete(struct list_node *item)

2、实例：

（1）、全局

struct synaptics_rmi4_exp_fn {

       enum exp_fn fn_type;

       bool inserted;

       int (*func_init)(struct synaptics_rmi4_data *rmi4_data);

       void (*func_remove)(struct synaptics_rmi4_data *rmi4_data);

       void (*func_attn)(struct synaptics_rmi4_data *rmi4_data,

                     unsigned char intr_mask);

       struct list_head link;

};

static bool exp_fn_inited;

static struct mutex exp_fn_list_mutex;

static struct list_head exp_fn_list;

（2）、初始化(probe中)

if (!exp_fn_inited) {

              mutex_init(&exp_fn_list_mutex);

              INIT_LIST_HEAD(&exp_fn_list);

              exp_fn_inited = 1;

       }

（3）、添加or删除一个list

void synaptics_rmi4_new_function(enum exp_fn fn_type, bool insert,

              int (*func_init)(struct synaptics_rmi4_data *rmi4_data),

              void (*func_remove)(struct synaptics_rmi4_data *rmi4_data),

              void (*func_attn)(struct synaptics_rmi4_data *rmi4_data,

              unsigned char intr_mask))

{

       struct synaptics_rmi4_exp_fn *exp_fhandler;

       if (!exp_fn_inited) {

              mutex_init(&exp_fn_list_mutex);

              INIT_LIST_HEAD(&exp_fn_list);

              exp_fn_inited = 1;

       }

       mutex_lock(&exp_fn_list_mutex);

       if (insert) {

              exp_fhandler = kzalloc(sizeof(*exp_fhandler), GFP_KERNEL);

              if (!exp_fhandler) {

                     pr_err("%s: Failed to alloc mem for expansion function\n",

                                   __func__);

                     goto exit;

              }

              exp_fhandler->fn_type = fn_type;

              exp_fhandler->func_init = func_init;

              exp_fhandler->func_attn = func_attn;

              exp_fhandler->func_remove = func_remove;

              exp_fhandler->inserted = false;

              list_add_tail(&exp_fhandler->link, &exp_fn_list);

       } else {

              if (!list_empty(&exp_fn_list)) {

                     list_for_each_entry(exp_fhandler, &exp_fn_list, link) {

                            if (exp_fhandler->func_init == func_init) {

                                   exp_fhandler->inserted = false;

                                   exp_fhandler->func_init = NULL;

                                   exp_fhandler->func_attn = NULL;

                                   goto exit;

                            }

                     }

              }

       }

exit:

       mutex_unlock(&exp_fn_list_mutex);

       return;

}

EXPORT_SYMBOL(synaptics_rmi4_new_function);