tools/usb/usbip/libsrc/list.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LIST_H
   3 #define _LIST_H
   4
   5 /* Stripped down implementation of linked list taken
   6  * from the Linux Kernel.
   7  */
   8
   9 /*
  10  * Simple doubly linked list implementation.
  11  *
  12  * Some of the internal functions ("__xxx") are useful when
  13  * manipulating whole lists rather than single entries, as
  14  * sometimes we already know the next/prev entries and we can
  15  * generate better code by using them directly rather than
  16  * using the generic single-entry routines.
  17  */
  18
  19 struct list_head {
  20         struct list_head *next, *prev;
  21 };
  22
  23 #define LIST_HEAD_INIT(name) { &(name), &(name) }
  24
  25 #define LIST_HEAD(name) \
  26         struct list_head name = LIST_HEAD_INIT(name)
  27
  28 static inline void INIT_LIST_HEAD(struct list_head *list)
  29 {
  30         list->next = list;
  31         list->prev = list;
  32 }
  33
  34 /*
  35  * Insert a new entry between two known consecutive entries.
  36  *
  37  * This is only for internal list manipulation where we know
  38  * the prev/next entries already!
  39  */
  40 static inline void __list_add(struct list_head *new,
  41                               struct list_head *prev,
  42                               struct list_head *next)
  43 {
  44         next->prev = new;
  45         new->next = next;
  46         new->prev = prev;
  47         prev->next = new;
  48 }
  49
  50 /**
  51  * list_add - add a new entry
  52  * @new: new entry to be added
  53  * @head: list head to add it after
  54  *
  55  * Insert a new entry after the specified head.
  56  * This is good for implementing stacks.
  57  */
  58 static inline void list_add(struct list_head *new, struct list_head *head)
  59 {
  60         __list_add(new, head, head->next);
  61 }
  62
  63 /*
  64  * Delete a list entry by making the prev/next entries
  65  * point to each other.
  66  *
  67  * This is only for internal list manipulation where we know
  68  * the prev/next entries already!
  69  */
  70 static inline void __list_del(struct list_head * prev, struct list_head * next)
  71 {
  72         next->prev = prev;
  73         prev->next = next;
  74 }
  75
  76 #define POISON_POINTER_DELTA 0
  77 #define LIST_POISON1  ((void *) 0x00100100 + POISON_POINTER_DELTA)
  78 #define LIST_POISON2  ((void *) 0x00200200 + POISON_POINTER_DELTA)
  79
  80 /**
  81  * list_del - deletes entry from list.
  82  * @entry: the element to delete from the list.
  83  * Note: list_empty() on entry does not return true after this, the entry is
  84  * in an undefined state.
  85  */
  86 static inline void __list_del_entry(struct list_head *entry)
  87 {
  88         __list_del(entry->prev, entry->next);
  89 }
  90
  91 static inline void list_del(struct list_head *entry)
  92 {
  93         __list_del(entry->prev, entry->next);
  94         entry->next = LIST_POISON1;
  95         entry->prev = LIST_POISON2;
  96 }
  97
  98 /**
  99  * list_entry - get the struct for this entry
 100  * @ptr:        the &struct list_head pointer.
 101  * @type:       the type of the struct this is embedded in.
 102  * @member:     the name of the list_head within the struct.
 103  */
 104 #define list_entry(ptr, type, member) \
 105         container_of(ptr, type, member)
 106 /**
 107  * list_for_each        -       iterate over a list
 108  * @pos:        the &struct list_head to use as a loop cursor.
 109  * @head:       the head for your list.
 110  */
 111 #define list_for_each(pos, head) \
 112         for (pos = (head)->next; pos != (head); pos = pos->next)
 113
 114 /**
 115  * list_for_each_safe - iterate over a list safe against removal of list entry
 116  * @pos:        the &struct list_head to use as a loop cursor.
 117  * @n:          another &struct list_head to use as temporary storage
 118  * @head:       the head for your list.
 119  */
 120 #define list_for_each_safe(pos, n, head) \
 121         for (pos = (head)->next, n = pos->next; pos != (head); \
 122                 pos = n, n = pos->next)
 123
 124 #define offsetof(TYPE, MEMBER) ((size_t) &((TYPE *)0)->MEMBER)
 125
 126 /**
 127  * container_of - cast a member of a structure out to the containing structure
 128  * @ptr:        the pointer to the member.
 129  * @type:       the type of the container struct this is embedded in.
 130  * @member:     the name of the member within the struct.
 131  *
 132  */
 133 #define container_of(ptr, type, member) ({                      \
 134         const typeof( ((type *)0)->member ) *__mptr = (ptr);    \
 135         (type *)( (char *)__mptr - offsetof(type,member) );})
 136
 137 #endif