6b13f685e
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/*
* Copyright (C) 2000 Takashi Iwai <tiwai@suse.de>
*
* Generic memory management routines for soundcard memory allocation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/mutex.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <sound/core.h>
#include <sound/util_mem.h>
MODULE_AUTHOR("Takashi Iwai");
MODULE_DESCRIPTION("Generic memory management routines for soundcard memory allocation");
MODULE_LICENSE("GPL");
#define get_memblk(p) list_entry(p, struct snd_util_memblk, list)
/*
* create a new memory manager
*/
struct snd_util_memhdr *
snd_util_memhdr_new(int memsize)
{
struct snd_util_memhdr *hdr;
hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
if (hdr == NULL)
return NULL;
hdr->size = memsize;
mutex_init(&hdr->block_mutex);
INIT_LIST_HEAD(&hdr->block);
return hdr;
}
/*
* free a memory manager
*/
void snd_util_memhdr_free(struct snd_util_memhdr *hdr)
{
struct list_head *p;
if (!hdr)
return;
/* release all blocks */
while ((p = hdr->block.next) != &hdr->block) {
list_del(p);
kfree(get_memblk(p));
}
kfree(hdr);
}
/*
* allocate a memory block (without mutex)
*/
struct snd_util_memblk *
__snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
{
struct snd_util_memblk *blk;
unsigned int units, prev_offset;
struct list_head *p;
if (snd_BUG_ON(!hdr || size <= 0))
return NULL;
/* word alignment */
units = size;
if (units & 1)
units++;
if (units > hdr->size)
return NULL;
/* look for empty block */
prev_offset = 0;
list_for_each(p, &hdr->block) {
blk = get_memblk(p);
if (blk->offset - prev_offset >= units)
goto __found;
prev_offset = blk->offset + blk->size;
}
if (hdr->size - prev_offset < units)
return NULL;
__found:
return __snd_util_memblk_new(hdr, units, p->prev);
}
/*
* create a new memory block with the given size
* the block is linked next to prev
*/
struct snd_util_memblk *
__snd_util_memblk_new(struct snd_util_memhdr *hdr, unsigned int units,
struct list_head *prev)
{
struct snd_util_memblk *blk;
blk = kmalloc(sizeof(struct snd_util_memblk) + hdr->block_extra_size,
GFP_KERNEL);
if (blk == NULL)
return NULL;
if (prev == &hdr->block)
blk->offset = 0;
else {
struct snd_util_memblk *p = get_memblk(prev);
blk->offset = p->offset + p->size;
}
blk->size = units;
list_add(&blk->list, prev);
hdr->nblocks++;
hdr->used += units;
return blk;
}
/*
* allocate a memory block (with mutex)
*/
struct snd_util_memblk *
snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
{
struct snd_util_memblk *blk;
mutex_lock(&hdr->block_mutex);
blk = __snd_util_mem_alloc(hdr, size);
mutex_unlock(&hdr->block_mutex);
return blk;
}
/*
* remove the block from linked-list and free resource
* (without mutex)
*/
void
__snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
{
list_del(&blk->list);
hdr->nblocks--;
hdr->used -= blk->size;
kfree(blk);
}
/*
* free a memory block (with mutex)
*/
int snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
{
if (snd_BUG_ON(!hdr || !blk))
return -EINVAL;
mutex_lock(&hdr->block_mutex);
__snd_util_mem_free(hdr, blk);
mutex_unlock(&hdr->block_mutex);
return 0;
}
/*
* return available memory size
*/
int snd_util_mem_avail(struct snd_util_memhdr *hdr)
{
unsigned int size;
mutex_lock(&hdr->block_mutex);
size = hdr->size - hdr->used;
mutex_unlock(&hdr->block_mutex);
return size;
}
EXPORT_SYMBOL(snd_util_memhdr_new);
EXPORT_SYMBOL(snd_util_memhdr_free);
EXPORT_SYMBOL(snd_util_mem_alloc);
EXPORT_SYMBOL(snd_util_mem_free);
EXPORT_SYMBOL(snd_util_mem_avail);
EXPORT_SYMBOL(__snd_util_mem_alloc);
EXPORT_SYMBOL(__snd_util_mem_free);
EXPORT_SYMBOL(__snd_util_memblk_new);
/*
* INIT part
*/
static int __init alsa_util_mem_init(void)
{
return 0;
}
static void __exit alsa_util_mem_exit(void)
{
}
module_init(alsa_util_mem_init)
module_exit(alsa_util_mem_exit)
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