sys/dev/drm/drm_subr_hash.c

   1 /*-
   2  * Copyright (c) 1982, 1986, 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  * (c) UNIX System Laboratories, Inc.
   5  * All or some portions of this file are derived from material licensed
   6  * to the University of California by American Telephone and Telegraph
   7  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
   8  * the permission of UNIX System Laboratories, Inc.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 4. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  *
  34  *      @(#)kern_subr.c 8.3 (Berkeley) 1/21/94
  35  * __FBSDID("$FreeBSD: src/sys/kern/subr_hash.c,v 1.1 2010/02/21 19:53:33 ed Exp $");
  36  */
  37
  38 #include "dev/drm/drmP.h"
  39 #include "dev/drm/drm_priv_hash.h"
  40
  41 /* From FreeBSD's sys/systm.h */
  42 #ifndef HASH_NOWAIT
  43 #define HASH_NOWAIT     0x00000001
  44 #endif
  45 #ifndef HASH_WAITOK
  46 #define HASH_WAITOK     0x00000002
  47 #endif
  48
  49 /*
  50  * General routine to allocate a hash table with control of memory flags.
  51  */
  52 void *
  53 drm_hashinit_flags(int elements, struct malloc_type *type, u_long *hashmask,
  54     int flags)
  55 {
  56         long hashsize;
  57         LIST_HEAD(generic, generic) *hashtbl;
  58         int i;
  59
  60         if (elements <= 0)
  61                 panic("hashinit: bad elements");
  62
  63         /* Exactly one of HASH_WAITOK and HASH_NOWAIT must be set. */
  64         KASSERT((flags & HASH_WAITOK) ^ (flags & HASH_NOWAIT),
  65             ("Bad flags (0x%x) passed to hashinit_flags", flags));
  66
  67         for (hashsize = 1; hashsize <= elements; hashsize <<= 1)
  68                 continue;
  69         hashsize >>= 1;
  70
  71         if (flags & HASH_NOWAIT)
  72                 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl),
  73                     type, M_NOWAIT);
  74         else
  75                 hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl),
  76                     type, M_WAITOK);
  77
  78         if (hashtbl != NULL) {
  79                 for (i = 0; i < hashsize; i++)
  80                         LIST_INIT(&hashtbl[i]);
  81                 *hashmask = hashsize - 1;
  82         }
  83         return (hashtbl);
  84 }
  85
  86 /*
  87  * Allocate and initialize a hash table with default flag: may sleep.
  88  */
  89 void *
  90 drm_hashinit(int elements, struct malloc_type *type, u_long *hashmask)
  91 {
  92
  93         return (drm_hashinit_flags(elements, type, hashmask, HASH_WAITOK));
  94 }
  95
  96 void
  97 drm_hashdestroy(void *vhashtbl, struct malloc_type *type, u_long hashmask)
  98 {
  99         LIST_HEAD(generic, generic) *hashtbl, *hp;
 100
 101         hashtbl = vhashtbl;
 102         for (hp = hashtbl; hp <= &hashtbl[hashmask]; hp++)
 103                 if (!LIST_EMPTY(hp))
 104                         panic("hashdestroy: hash not empty");
 105         free(hashtbl, type);
 106 }
 107
 108 static const int primes[] = { 1, 13, 31, 61, 127, 251, 509, 761, 1021, 1531,
 109                         2039, 2557, 3067, 3583, 4093, 4603, 5119, 5623, 6143,
 110                         6653, 7159, 7673, 8191, 12281, 16381, 24571, 32749 };
 111 #define NPRIMES (sizeof(primes) / sizeof(primes[0]))
 112
 113 /*
 114  * General routine to allocate a prime number sized hash table.
 115  */
 116 void *
 117 drm_phashinit(int elements, struct malloc_type *type, u_long *nentries)
 118 {
 119         long hashsize;
 120         LIST_HEAD(generic, generic) *hashtbl;
 121         int i;
 122
 123         if (elements <= 0)
 124                 panic("phashinit: bad elements");
 125         for (i = 1, hashsize = primes[1]; hashsize <= elements;) {
 126                 i++;
 127                 if (i == NPRIMES)
 128                         break;
 129                 hashsize = primes[i];
 130         }
 131         hashsize = primes[i - 1];
 132         hashtbl = malloc((u_long)hashsize * sizeof(*hashtbl), type, M_WAITOK);
 133         for (i = 0; i < hashsize; i++)
 134                 LIST_INIT(&hashtbl[i]);
 135         *nentries = hashsize;
 136         return (hashtbl);
 137 }