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  */
  20 struct ulist_iterator {
  21         struct list_head *cur_list;  /* hint to start search */
  22 };
  23
  24 /*
  25  * element of the list
  26  */
  27 struct 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
  35 struct 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
  45 void ulist_init(struct ulist *ulist);
  46 void ulist_release(struct ulist *ulist);
  47 void ulist_reinit(struct ulist *ulist);
  48 struct ulist *ulist_alloc(gfp_t gfp_mask);
  49 void ulist_free(struct ulist *ulist);
  50 int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
  51 int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
  52                     u64 *old_aux, gfp_t gfp_mask);
  53 int ulist_del(struct ulist *ulist, u64 val, u64 aux);
  54
  55 /* just like ulist_add_merge() but take a pointer for the aux data */
  56 static 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
  69 struct 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