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_H__
   9 #define __ULIST_H__
  10
  11 #include "kerncompat.h"
  12 #include "list.h"
  13 #include "rbtree.h"
  14
  15 /*
  16  * ulist is a generic data structure to hold a collection of unique u64
  17  * values. The only operations it supports is adding to the list and
  18  * enumerating it.
  19  * It is possible to store an auxiliary value along with the key.
  20  *
  21  */
  22 struct ulist_iterator {
  23 #ifdef CONFIG_BTRFS_DEBUG
  24         int i;
  25 #endif
  26         struct list_head *cur_list;  /* hint to start search */
  27 };
  28
  29 /*
  30  * element of the list
  31  */
  32 struct ulist_node {
  33         u64 val;                /* value to store */
  34         u64 aux;                /* auxiliary value saved along with the val */
  35
  36 #ifdef CONFIG_BTRFS_DEBUG
  37         int seqnum;             /* sequence number this node is added */
  38 #endif
  39
  40         struct list_head list;  /* used to link node */
  41         struct rb_node rb_node; /* used to speed up search */
  42 };
  43
  44 struct ulist {
  45         /*
  46          * number of elements stored in list
  47          */
  48         unsigned long nnodes;
  49
  50         struct list_head nodes;
  51         struct rb_root root;
  52 };
  53
  54 void ulist_init(struct ulist *ulist);
  55 void ulist_reinit(struct ulist *ulist);
  56 struct ulist *ulist_alloc(gfp_t gfp_mask);
  57 void ulist_free(struct ulist *ulist);
  58 int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
  59 int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
  60                     u64 *old_aux, gfp_t gfp_mask);
  61
  62 /* just like ulist_add_merge() but take a pointer for the aux data */
  63 static 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
  76 struct 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