util_mem.c
4.55 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
/*
* 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)