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/types.h>
  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  */
  21 struct ulist_iterator {
  22         struct list_head *cur_list;  /* hint to start search */
  23 };
  24
  25 /*
  26  * element of the list
  27  */
  28 struct ulist_node {
  29         u64 val;                /* value to store */
  30         u64 aux;                /* auxiliary value saved along with the val */
  31
  32         struct list_head list;  /* used to link node */
  33         struct rb_node rb_node; /* used to speed up search */
  34 };
  35
  36 struct ulist {
  37         /*
  38          * number of elements stored in list
  39          */
  40         unsigned long nnodes;
  41
  42         struct list_head nodes;
  43         struct rb_root root;
  44         struct ulist_node *prealloc;
  45 };
  46
  47 void ulist_init(struct ulist *ulist);
  48 void ulist_release(struct ulist *ulist);
  49 void ulist_reinit(struct ulist *ulist);
  50 struct ulist *ulist_alloc(gfp_t gfp_mask);
  51 void ulist_prealloc(struct ulist *ulist, gfp_t mask);
  52 void ulist_free(struct ulist *ulist);
  53 int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
  54 int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
  55                     u64 *old_aux, gfp_t gfp_mask);
  56 int ulist_del(struct ulist *ulist, u64 val, u64 aux);
  57
  58 /* just like ulist_add_merge() but take a pointer for the aux data */
  59 static inline int ulist_add_merge_ptr(struct ulist *ulist, u64 val, void *aux,
  60                                       void **old_aux, gfp_t gfp_mask)
  61 {
  62 #if BITS_PER_LONG == 32
  63         u64 old64 = (uintptr_t)*old_aux;
  64         int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
  65         *old_aux = (void *)((uintptr_t)old64);
  66         return ret;
  67 #else
  68         return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
  69 #endif
  70 }
  71
  72 struct ulist_node *ulist_next(const struct ulist *ulist,
  73                               struct ulist_iterator *uiter);
  74
  75 #define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)
  76
  77 #endif