Line data    Source code

       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           0 :         return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
      66             : #endif
      67             : }
      68             : 
      69             : struct ulist_node *ulist_next(const struct ulist *ulist,
      70             :                               struct ulist_iterator *uiter);
      71             : 
      72             : #define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)
      73             : 
      74             : #endif