LXR linux/fs/btrfs/ulist.h

   1/*
   2 * Copyright (C) 2011 STRATO AG
   3 * written by Arne Jansen <sensille@gmx.net>
   4 * Distributed under the GNU GPL license version 2.
   5 *
   6 */
   7
   8#ifndef __ULIST__
   9#define __ULIST__
  10
  11#include <linux/list.h>
  12#include <linux/rbtree.h>
  13
  14/*
  15 * ulist is a generic data structure to hold a collection of unique u64
  16 * values. The only operations it supports is adding to the list and
  17 * enumerating it.
  18 * It is possible to store an auxiliary value along with the key.
  19 *
  20 */
  21struct ulist_iterator {
  22#ifdef CONFIG_BTRFS_DEBUG
  23        int i;
  24#endif
  25        struct list_head *cur_list;  /* hint to start search */
  26};
  27
  28/*
  29 * element of the list
  30 */
  31struct ulist_node {
  32        u64 val;                /* value to store */
  33        u64 aux;                /* auxiliary value saved along with the val */
  34
  35#ifdef CONFIG_BTRFS_DEBUG
  36        int seqnum;             /* sequence number this node is added */
  37#endif
  38
  39        struct list_head list;  /* used to link node */
  40        struct rb_node rb_node; /* used to speed up search */
  41};
  42
  43struct ulist {
  44        /*
  45         * number of elements stored in list
  46         */
  47        unsigned long nnodes;
  48
  49        struct list_head nodes;
  50        struct rb_root root;
  51};
  52
  53void ulist_init(struct ulist *ulist);
  54void ulist_reinit(struct ulist *ulist);
  55struct ulist *ulist_alloc(gfp_t gfp_mask);
  56void ulist_free(struct ulist *ulist);
  57int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
  58int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
  59                    u64 *old_aux, gfp_t gfp_mask);
  60int ulist_del(struct ulist *ulist, u64 val, u64 aux);
  61
  62/* just like ulist_add_merge() but take a pointer for the aux data */
  63static inline int ulist_add_merge_ptr(struct ulist *ulist, u64 val, void *aux,
  64                                      void **old_aux, gfp_t gfp_mask)
  65{
  66#if BITS_PER_LONG == 32
  67        u64 old64 = (uintptr_t)*old_aux;
  68        int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
  69        *old_aux = (void *)((uintptr_t)old64);
  70        return ret;
  71#else
  72        return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
  73#endif
  74}
  75
  76struct ulist_node *ulist_next(struct ulist *ulist,
  77                              struct ulist_iterator *uiter);
  78
  79#define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)
  80
  81#endif
  82