sound/synth/util_mem.c

   1 /*
   2  *  Copyright (C) 2000 Takashi Iwai <tiwai@suse.de>
   3  *
   4  *  Generic memory management routines for soundcard memory allocation
   5  *
   6  *   This program is free software; you can redistribute it and/or modify
   7  *   it under the terms of the GNU General Public License as published by
   8  *   the Free Software Foundation; either version 2 of the License, or
   9  *   (at your option) any later version.
  10  *
  11  *   This program is distributed in the hope that it will be useful,
  12  *   but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  *   GNU General Public License for more details.
  15  *
  16  *   You should have received a copy of the GNU General Public License
  17  *   along with this program; if not, write to the Free Software
  18  *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  19  */
  20
  21 #include <linux/mutex.h>
  22 #include <linux/init.h>
  23 #include <linux/slab.h>
  24 #include <sound/core.h>
  25 #include <sound/util_mem.h>
  26
  27 MODULE_AUTHOR("Takashi Iwai");
  28 MODULE_DESCRIPTION("Generic memory management routines for soundcard memory allocation");
  29 MODULE_LICENSE("GPL");
  30
  31 #define get_memblk(p)   list_entry(p, struct snd_util_memblk, list)
  32
  33 /*
  34  * create a new memory manager
  35  */
  36 struct snd_util_memhdr *
  37 snd_util_memhdr_new(int memsize)
  38 {
  39         struct snd_util_memhdr *hdr;
  40
  41         hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
  42         if (hdr == NULL)
  43                 return NULL;
  44         hdr->size = memsize;
  45         mutex_init(&hdr->block_mutex);
  46         INIT_LIST_HEAD(&hdr->block);
  47
  48         return hdr;
  49 }
  50
  51 /*
  52  * free a memory manager
  53  */
  54 void snd_util_memhdr_free(struct snd_util_memhdr *hdr)
  55 {
  56         struct list_head *p;
  57
  58         if (!hdr)
  59                 return;
  60         /* release all blocks */
  61         while ((p = hdr->block.next) != &hdr->block) {
  62                 list_del(p);
  63                 kfree(get_memblk(p));
  64         }
  65         kfree(hdr);
  66 }
  67
  68 /*
  69  * allocate a memory block (without mutex)
  70  */
  71 struct snd_util_memblk *
  72 __snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
  73 {
  74         struct snd_util_memblk *blk;
  75         unsigned int units, prev_offset;
  76         struct list_head *p;
  77
  78         if (snd_BUG_ON(!hdr || size <= 0))
  79                 return NULL;
  80
  81         /* word alignment */
  82         units = size;
  83         if (units & 1)
  84                 units++;
  85         if (units > hdr->size)
  86                 return NULL;
  87
  88         /* look for empty block */
  89         prev_offset = 0;
  90         list_for_each(p, &hdr->block) {
  91                 blk = get_memblk(p);
  92                 if (blk->offset - prev_offset >= units)
  93                         goto __found;
  94                 prev_offset = blk->offset + blk->size;
  95         }
  96         if (hdr->size - prev_offset < units)
  97                 return NULL;
  98
  99 __found:
 100         return __snd_util_memblk_new(hdr, units, p->prev);
 101 }
 102
 103
 104 /*
 105  * create a new memory block with the given size
 106  * the block is linked next to prev
 107  */
 108 struct snd_util_memblk *
 109 __snd_util_memblk_new(struct snd_util_memhdr *hdr, unsigned int units,
 110                       struct list_head *prev)
 111 {
 112         struct snd_util_memblk *blk;
 113
 114         blk = kmalloc(sizeof(struct snd_util_memblk) + hdr->block_extra_size,
 115                       GFP_KERNEL);
 116         if (blk == NULL)
 117                 return NULL;
 118
 119         if (prev == &hdr->block)
 120                 blk->offset = 0;
 121         else {
 122                 struct snd_util_memblk *p = get_memblk(prev);
 123                 blk->offset = p->offset + p->size;
 124         }
 125         blk->size = units;
 126         list_add(&blk->list, prev);
 127         hdr->nblocks++;
 128         hdr->used += units;
 129         return blk;
 130 }
 131
 132
 133 /*
 134  * allocate a memory block (with mutex)
 135  */
 136 struct snd_util_memblk *
 137 snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
 138 {
 139         struct snd_util_memblk *blk;
 140         mutex_lock(&hdr->block_mutex);
 141         blk = __snd_util_mem_alloc(hdr, size);
 142         mutex_unlock(&hdr->block_mutex);
 143         return blk;
 144 }
 145
 146
 147 /*
 148  * remove the block from linked-list and free resource
 149  * (without mutex)
 150  */
 151 void
 152 __snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
 153 {
 154         list_del(&blk->list);
 155         hdr->nblocks--;
 156         hdr->used -= blk->size;
 157         kfree(blk);
 158 }
 159
 160 /*
 161  * free a memory block (with mutex)
 162  */
 163 int snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
 164 {
 165         if (snd_BUG_ON(!hdr || !blk))
 166                 return -EINVAL;
 167
 168         mutex_lock(&hdr->block_mutex);
 169         __snd_util_mem_free(hdr, blk);
 170         mutex_unlock(&hdr->block_mutex);
 171         return 0;
 172 }
 173
 174 /*
 175  * return available memory size
 176  */
 177 int snd_util_mem_avail(struct snd_util_memhdr *hdr)
 178 {
 179         unsigned int size;
 180         mutex_lock(&hdr->block_mutex);
 181         size = hdr->size - hdr->used;
 182         mutex_unlock(&hdr->block_mutex);
 183         return size;
 184 }
 185
 186
 187 EXPORT_SYMBOL(snd_util_memhdr_new);
 188 EXPORT_SYMBOL(snd_util_memhdr_free);
 189 EXPORT_SYMBOL(snd_util_mem_alloc);
 190 EXPORT_SYMBOL(snd_util_mem_free);
 191 EXPORT_SYMBOL(snd_util_mem_avail);
 192 EXPORT_SYMBOL(__snd_util_mem_alloc);
 193 EXPORT_SYMBOL(__snd_util_mem_free);
 194 EXPORT_SYMBOL(__snd_util_memblk_new);
 195
 196 /*
 197  *  INIT part
 198  */
 199
 200 static int __init alsa_util_mem_init(void)
 201 {
 202         return 0;
 203 }
 204
 205 static void __exit alsa_util_mem_exit(void)
 206 {
 207 }
 208
 209 module_init(alsa_util_mem_init)
 210 module_exit(alsa_util_mem_exit)