list.h

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/* SPDX-License-Identifier: GPL-2.0-only */
 
/*
 * The content of this file is mainly copied/inspired from Linux kernel
 * code in include/linux/list.h, include/linux/types.h
 * Last aligned with kernel v5.12:
 * - skip the functions hlist_unhashed_lockless() and __list_del_clearprev()
 *   that are relevant only in kernel;
 * - Remove non-standard GCC extension "omitted conditional operand" from
 *   list_prepare_entry;
 * - expand READ_ONCE, WRITE_ONCE, smp_load_acquire, smp_store_release;
 * - make comments compatible with doxygen.
 *
 * There is an example of using this file in contrib/list_example.c.
 */
 
#ifndef OPENOCD_HELPER_LIST_H
#define OPENOCD_HELPER_LIST_H
 
/* begin local changes */
#include <helper/types.h>
 
#define LIST_POISON1 NULL
#define LIST_POISON2 NULL
 
struct list_head {
    struct list_head *next, *prev;
};
 
struct hlist_head {
    struct hlist_node *first;
};
 
struct hlist_node {
    struct hlist_node *next, **pprev;
};
/* end local changes */
 
/*
 * Circular 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)
{
    list->next = list;
    list->prev = list;
}
 
#ifdef CONFIG_DEBUG_LIST
extern bool __list_add_valid(struct list_head *new,
                  struct list_head *prev,
                  struct list_head *next);
extern bool __list_del_entry_valid(struct list_head *entry);
#else
static inline bool __list_add_valid(struct list_head *new,
                struct list_head *prev,
                struct list_head *next)
{
    return true;
}
static inline bool __list_del_entry_valid(struct list_head *entry)
{
    return true;
}
#endif
 
/*
 * 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)
{
    if (!__list_add_valid(new, prev, next))
        return;
 
    next->prev = new;
    new->next = next;
    new->prev = prev;
    prev->next = new;
}
 
static inline void list_add(struct list_head *new, struct list_head *head)
{
    __list_add(new, head, head->next);
}
 
 
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;
}
 
/* Ignore kernel __list_del_clearprev() */
 
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;
}
 
static inline void list_replace(struct list_head *old,
                struct list_head *new)
{
    new->next = old->next;
    new->next->prev = new;
    new->prev = old->prev;
    new->prev->next = new;
}
 
static inline void list_replace_init(struct list_head *old,
                     struct list_head *new)
{
    list_replace(old, new);
    INIT_LIST_HEAD(old);
}
 
static inline void list_swap(struct list_head *entry1,
                 struct list_head *entry2)
{
    struct list_head *pos = entry2->prev;
 
    list_del(entry2);
    list_replace(entry1, entry2);
    if (pos == entry1)
        pos = entry2;
    list_add(entry1, pos);
}
 
static inline void list_del_init(struct list_head *entry)
{
    __list_del_entry(entry);
    INIT_LIST_HEAD(entry);
}
 
static inline void list_move(struct list_head *list, struct list_head *head)
{
    __list_del_entry(list);
    list_add(list, head);
}
 
static inline void list_move_tail(struct list_head *list,
                  struct list_head *head)
{
    __list_del_entry(list);
    list_add_tail(list, head);
}
 
static inline void list_bulk_move_tail(struct list_head *head,
                       struct list_head *first,
                       struct list_head *last)
{
    first->prev->next = last->next;
    last->next->prev = first->prev;
 
    head->prev->next = first;
    first->prev = head->prev;
 
    last->next = head;
    head->prev = last;
}
 
static inline int list_is_first(const struct list_head *list,
                    const struct list_head *head)
{
    return list->prev == head;
}
 
static inline int list_is_last(const struct list_head *list,
                const struct list_head *head)
{
    return list->next == head;
}
 
static inline int list_empty(const struct list_head *head)
{
    return head->next == head;
}
 
static inline void list_del_init_careful(struct list_head *entry)
{
    __list_del_entry(entry);
    entry->prev = entry;
    entry->next = entry;
}
 
static inline int list_empty_careful(const struct list_head *head)
{
    struct list_head *next = head->next;
    return (next == head) && (next == head->prev);
}
 
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);
    }
}
 
static inline void list_rotate_to_front(struct list_head *list,
                    struct list_head *head)
{
    /*
     * Deletes the list head from the list denoted by @a head and
     * places it as the tail of @a list, this effectively rotates the
     * list so that @a list is at the front.
     */
    list_move_tail(head, list);
}
 
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;
}
 
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_cut_before(struct list_head *list,
                   struct list_head *head,
                   struct list_head *entry)
{
    if (head->next == entry) {
        INIT_LIST_HEAD(list);
        return;
    }
    list->next = head->next;
    list->next->prev = list;
    list->prev = entry->prev;
    list->prev->next = list;
    head->next = entry;
    entry->prev = head;
}
 
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;
}
 
static inline void list_splice(const struct list_head *list,
                struct list_head *head)
{
    if (!list_empty(list))
        __list_splice(list, head, head->next);
}
 
static inline void list_splice_tail(struct list_head *list,
                struct list_head *head)
{
    if (!list_empty(list))
        __list_splice(list, head->prev, head);
}
 
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);
    }
}
 
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);
    }
}
 
#define list_entry(ptr, type, member) \
    container_of(ptr, type, member)
 
#define list_first_entry(ptr, type, member) \
    list_entry((ptr)->next, type, member)
 
#define list_last_entry(ptr, type, member) \
    list_entry((ptr)->prev, type, member)
 
#define list_first_entry_or_null(ptr, type, member) ({ \
    struct list_head *head__ = (ptr); \
    struct list_head *pos__ = head__->next; \
    pos__ != head__ ? list_entry(pos__, type, member) : NULL; \
})
 
#define list_next_entry(pos, member) \
    list_entry((pos)->member.next, typeof(*(pos)), member)
 
#define list_prev_entry(pos, member) \
    list_entry((pos)->member.prev, typeof(*(pos)), member)
 
#define list_for_each(pos, head) \
    for (pos = (head)->next; pos != (head); pos = pos->next)
 
#define list_for_each_continue(pos, head) \
    for (pos = pos->next; pos != (head); pos = pos->next)
 
#define list_for_each_prev(pos, head) \
    for (pos = (head)->prev; pos != (head); pos = pos->prev)
 
#define list_for_each_safe(pos, n, head) \
    for (pos = (head)->next, n = pos->next; pos != (head); \
        pos = n, n = pos->next)
 
#define list_for_each_prev_safe(pos, n, head) \
    for (pos = (head)->prev, n = pos->prev; \
         pos != (head); \
         pos = n, n = pos->prev)
 
#define list_entry_is_head(pos, head, member)               \
    (&pos->member == (head))
 
#define list_for_each_entry(pos, head, member)              \
    for (pos = list_first_entry(head, typeof(*pos), member);    \
         !list_entry_is_head(pos, head, member);            \
         pos = list_next_entry(pos, member))
 
#define list_for_each_entry_reverse(pos, head, member)          \
    for (pos = list_last_entry(head, typeof(*pos), member);     \
         !list_entry_is_head(pos, head, member);            \
         pos = list_prev_entry(pos, member))
 
#define list_for_each_entry_direction(forward, pos, head, member)       \
    for (pos = forward ? list_first_entry(head, typeof(*pos), member)   \
                       : list_last_entry(head, typeof(*pos), member);   \
         !list_entry_is_head(pos, head, member);                        \
         pos = forward ? list_next_entry(pos, member)                   \
                       : list_prev_entry(pos, member))
 
#define list_prepare_entry(pos, head, member) \
    ((pos) ? (pos) : list_entry(head, typeof(*pos), member))
 
#define list_for_each_entry_continue(pos, head, member)     \
    for (pos = list_next_entry(pos, member);            \
         !list_entry_is_head(pos, head, member);            \
         pos = list_next_entry(pos, member))
 
#define list_for_each_entry_continue_reverse(pos, head, member)     \
    for (pos = list_prev_entry(pos, member);            \
         !list_entry_is_head(pos, head, member);            \
         pos = list_prev_entry(pos, member))
 
#define list_for_each_entry_from(pos, head, member)         \
    for (; !list_entry_is_head(pos, head, member);          \
         pos = list_next_entry(pos, member))
 
#define list_for_each_entry_from_reverse(pos, head, member)     \
    for (; !list_entry_is_head(pos, head, member);          \
         pos = list_prev_entry(pos, member))
 
#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);           \
         !list_entry_is_head(pos, head, member);            \
         pos = n, n = list_next_entry(n, member))
 
#define list_for_each_entry_safe_continue(pos, n, head, member)     \
    for (pos = list_next_entry(pos, member),                \
        n = list_next_entry(pos, member);               \
         !list_entry_is_head(pos, head, member);                \
         pos = n, n = list_next_entry(n, member))
 
#define list_for_each_entry_safe_from(pos, n, head, member)         \
    for (n = list_next_entry(pos, member);                  \
         !list_entry_is_head(pos, head, member);                \
         pos = n, n = list_next_entry(n, member))
 
#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);           \
         !list_entry_is_head(pos, head, member);            \
         pos = n, n = list_prev_entry(n, member))
 
#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;
}
 
/* Ignore kernel hlist_unhashed_lockless() */
 
static inline int hlist_empty(const struct hlist_head *h)
{
    return !h->first;
}
 
static inline void __hlist_del(struct hlist_node *n)
{
    struct hlist_node *next = n->next;
    struct hlist_node **pprev = n->pprev;
 
    *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;
    h->first = n;
    n->pprev = &h->first;
}
 
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;
    *(n->pprev) = n;
}
 
static inline void hlist_add_behind(struct hlist_node *n,
                    struct hlist_node *prev)
{
    n->next = prev->next;
    prev->next = n;
    n->pprev = &prev->next;
 
    if (n->next)
        n->next->pprev = &n->next;
}
 
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;
}
 
static inline bool
hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h)
{
    return !n->next && n->pprev == &h->first;
}
 
static inline void hlist_move_list(struct hlist_head *old,
                   struct hlist_head *new)
{
    new->first = old->first;
    if (new->first)
        new->first->pprev = &new->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; \
    })
 
#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))
 
#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))
 
#define hlist_for_each_entry_from(pos, member)              \
    for (; pos;                         \
         pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member))
 
#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 /* OPENOCD_HELPER_LIST_H */