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  */
  21 struct 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  */
  31 struct 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
  43 struct 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
  53 void ulist_init(struct ulist *ulist);
  54 void ulist_reinit(struct ulist *ulist);
  55 struct ulist *ulist_alloc(gfp_t gfp_mask);
  56 void ulist_free(struct ulist *ulist);
  57 int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
  58 int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
  59                     u64 *old_aux, gfp_t gfp_mask);
  60
  61 /* just like ulist_add_merge() but take a pointer for the aux data */
  62 static inline int ulist_add_merge_ptr(struct ulist *ulist, u64 val, void *aux,
  63                                       void **old_aux, gfp_t gfp_mask)
  64 {
  65 #if BITS_PER_LONG == 32
  66         u64 old64 = (uintptr_t)*old_aux;
  67         int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
  68         *old_aux = (void *)((uintptr_t)old64);
  69         return ret;
  70 #else
  71         return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
  72 #endif
  73 }
  74
  75 struct ulist_node *ulist_next(struct ulist *ulist,
  76                               struct ulist_iterator *uiter);
  77
  78 #define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)
  79
  80 #endif