LXR linux/fs/btrfs/ulist.h

   1/* SPDX-License-Identifier: GPL-2.0 */
   2/*
   3 * Copyright (C) 2011 STRATO AG
   4 * written by Arne Jansen <sensille@gmx.net>
   5 */
   6
   7#ifndef BTRFS_ULIST_H
   8#define BTRFS_ULIST_H
   9
  10#include <linux/list.h>
  11#include <linux/rbtree.h>
  12
  13/*
  14 * ulist is a generic data structure to hold a collection of unique u64
  15 * values. The only operations it supports is adding to the list and
  16 * enumerating it.
  17 * It is possible to store an auxiliary value along with the key.
  18 *
  19 */
  20struct ulist_iterator {
  21        struct list_head *cur_list;  /* hint to start search */
  22};
  23
  24/*
  25 * element of the list
  26 */
  27struct ulist_node {
  28        u64 val;                /* value to store */
  29        u64 aux;                /* auxiliary value saved along with the val */
  30
  31        struct list_head list;  /* used to link node */
  32        struct rb_node rb_node; /* used to speed up search */
  33};
  34
  35struct ulist {
  36        /*
  37         * number of elements stored in list
  38         */
  39        unsigned long nnodes;
  40
  41        struct list_head nodes;
  42        struct rb_root root;
  43};
  44
  45void ulist_init(struct ulist *ulist);
  46void ulist_release(struct ulist *ulist);
  47void ulist_reinit(struct ulist *ulist);
  48struct ulist *ulist_alloc(gfp_t gfp_mask);
  49void ulist_free(struct ulist *ulist);
  50int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
  51int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
  52                    u64 *old_aux, gfp_t gfp_mask);
  53int ulist_del(struct ulist *ulist, u64 val, u64 aux);
  54
  55/* just like ulist_add_merge() but take a pointer for the aux data */
  56static inline int ulist_add_merge_ptr(struct ulist *ulist, u64 val, void *aux,
  57                                      void **old_aux, gfp_t gfp_mask)
  58{
  59#if BITS_PER_LONG == 32
  60        u64 old64 = (uintptr_t)*old_aux;
  61        int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
  62        *old_aux = (void *)((uintptr_t)old64);
  63        return ret;
  64#else
  65        return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
  66#endif
  67}
  68
  69struct ulist_node *ulist_next(struct ulist *ulist,
  70                              struct ulist_iterator *uiter);
  71
  72#define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)
  73
  74#endif
  75