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kernel/linux-rt-4.4.41/fs/btrfs/ulist.h 2.02 KB
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  /*
   * Copyright (C) 2011 STRATO AG
   * written by Arne Jansen <sensille@gmx.net>
   * Distributed under the GNU GPL license version 2.
   *
   */
  
  #ifndef __ULIST__
  #define __ULIST__
  
  #include <linux/list.h>
  #include <linux/rbtree.h>
  
  /*
   * ulist is a generic data structure to hold a collection of unique u64
   * values. The only operations it supports is adding to the list and
   * enumerating it.
   * It is possible to store an auxiliary value along with the key.
   *
   */
  struct ulist_iterator {
  #ifdef CONFIG_BTRFS_DEBUG
  	int i;
  #endif
  	struct list_head *cur_list;  /* hint to start search */
  };
  
  /*
   * element of the list
   */
  struct ulist_node {
  	u64 val;		/* value to store */
  	u64 aux;		/* auxiliary value saved along with the val */
  
  #ifdef CONFIG_BTRFS_DEBUG
  	int seqnum;		/* sequence number this node is added */
  #endif
  
  	struct list_head list;  /* used to link node */
  	struct rb_node rb_node;	/* used to speed up search */
  };
  
  struct ulist {
  	/*
  	 * number of elements stored in list
  	 */
  	unsigned long nnodes;
  
  	struct list_head nodes;
  	struct rb_root root;
  };
  
  void ulist_init(struct ulist *ulist);
  void ulist_reinit(struct ulist *ulist);
  struct ulist *ulist_alloc(gfp_t gfp_mask);
  void ulist_free(struct ulist *ulist);
  int ulist_add(struct ulist *ulist, u64 val, u64 aux, gfp_t gfp_mask);
  int ulist_add_merge(struct ulist *ulist, u64 val, u64 aux,
  		    u64 *old_aux, gfp_t gfp_mask);
  int ulist_del(struct ulist *ulist, u64 val, u64 aux);
  
  /* just like ulist_add_merge() but take a pointer for the aux data */
  static inline int ulist_add_merge_ptr(struct ulist *ulist, u64 val, void *aux,
  				      void **old_aux, gfp_t gfp_mask)
  {
  #if BITS_PER_LONG == 32
  	u64 old64 = (uintptr_t)*old_aux;
  	int ret = ulist_add_merge(ulist, val, (uintptr_t)aux, &old64, gfp_mask);
  	*old_aux = (void *)((uintptr_t)old64);
  	return ret;
  #else
  	return ulist_add_merge(ulist, val, (u64)aux, (u64 *)old_aux, gfp_mask);
  #endif
  }
  
  struct ulist_node *ulist_next(struct ulist *ulist,
  			      struct ulist_iterator *uiter);
  
  #define ULIST_ITER_INIT(uiter) ((uiter)->cur_list = NULL)
  
  #endif