Merge tag 'for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mst/vhost
[cris-mirror.git] / sound / synth / util_mem.c
blob8e34bc4e07ec3a62d93d9a0d0ca693a77ba9749f
1 /*
2 * Copyright (C) 2000 Takashi Iwai <tiwai@suse.de>
4 * Generic memory management routines for soundcard memory allocation
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.
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.
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
21 #include <linux/mutex.h>
22 #include <linux/init.h>
23 #include <linux/slab.h>
24 #include <linux/module.h>
25 #include <sound/core.h>
26 #include <sound/util_mem.h>
28 MODULE_AUTHOR("Takashi Iwai");
29 MODULE_DESCRIPTION("Generic memory management routines for soundcard memory allocation");
30 MODULE_LICENSE("GPL");
32 #define get_memblk(p) list_entry(p, struct snd_util_memblk, list)
35 * create a new memory manager
37 struct snd_util_memhdr *
38 snd_util_memhdr_new(int memsize)
40 struct snd_util_memhdr *hdr;
42 hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
43 if (hdr == NULL)
44 return NULL;
45 hdr->size = memsize;
46 mutex_init(&hdr->block_mutex);
47 INIT_LIST_HEAD(&hdr->block);
49 return hdr;
53 * free a memory manager
55 void snd_util_memhdr_free(struct snd_util_memhdr *hdr)
57 struct list_head *p;
59 if (!hdr)
60 return;
61 /* release all blocks */
62 while ((p = hdr->block.next) != &hdr->block) {
63 list_del(p);
64 kfree(get_memblk(p));
66 kfree(hdr);
70 * allocate a memory block (without mutex)
72 struct snd_util_memblk *
73 __snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
75 struct snd_util_memblk *blk;
76 unsigned int units, prev_offset;
77 struct list_head *p;
79 if (snd_BUG_ON(!hdr || size <= 0))
80 return NULL;
82 /* word alignment */
83 units = size;
84 if (units & 1)
85 units++;
86 if (units > hdr->size)
87 return NULL;
89 /* look for empty block */
90 prev_offset = 0;
91 list_for_each(p, &hdr->block) {
92 blk = get_memblk(p);
93 if (blk->offset - prev_offset >= units)
94 goto __found;
95 prev_offset = blk->offset + blk->size;
97 if (hdr->size - prev_offset < units)
98 return NULL;
100 __found:
101 return __snd_util_memblk_new(hdr, units, p->prev);
106 * create a new memory block with the given size
107 * the block is linked next to prev
109 struct snd_util_memblk *
110 __snd_util_memblk_new(struct snd_util_memhdr *hdr, unsigned int units,
111 struct list_head *prev)
113 struct snd_util_memblk *blk;
115 blk = kmalloc(sizeof(struct snd_util_memblk) + hdr->block_extra_size,
116 GFP_KERNEL);
117 if (blk == NULL)
118 return NULL;
120 if (prev == &hdr->block)
121 blk->offset = 0;
122 else {
123 struct snd_util_memblk *p = get_memblk(prev);
124 blk->offset = p->offset + p->size;
126 blk->size = units;
127 list_add(&blk->list, prev);
128 hdr->nblocks++;
129 hdr->used += units;
130 return blk;
135 * allocate a memory block (with mutex)
137 struct snd_util_memblk *
138 snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
140 struct snd_util_memblk *blk;
141 mutex_lock(&hdr->block_mutex);
142 blk = __snd_util_mem_alloc(hdr, size);
143 mutex_unlock(&hdr->block_mutex);
144 return blk;
149 * remove the block from linked-list and free resource
150 * (without mutex)
152 void
153 __snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
155 list_del(&blk->list);
156 hdr->nblocks--;
157 hdr->used -= blk->size;
158 kfree(blk);
162 * free a memory block (with mutex)
164 int snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
166 if (snd_BUG_ON(!hdr || !blk))
167 return -EINVAL;
169 mutex_lock(&hdr->block_mutex);
170 __snd_util_mem_free(hdr, blk);
171 mutex_unlock(&hdr->block_mutex);
172 return 0;
176 * return available memory size
178 int snd_util_mem_avail(struct snd_util_memhdr *hdr)
180 unsigned int size;
181 mutex_lock(&hdr->block_mutex);
182 size = hdr->size - hdr->used;
183 mutex_unlock(&hdr->block_mutex);
184 return size;
188 EXPORT_SYMBOL(snd_util_memhdr_new);
189 EXPORT_SYMBOL(snd_util_memhdr_free);
190 EXPORT_SYMBOL(snd_util_mem_alloc);
191 EXPORT_SYMBOL(snd_util_mem_free);
192 EXPORT_SYMBOL(snd_util_mem_avail);
193 EXPORT_SYMBOL(__snd_util_mem_alloc);
194 EXPORT_SYMBOL(__snd_util_mem_free);
195 EXPORT_SYMBOL(__snd_util_memblk_new);
198 * INIT part
201 static int __init alsa_util_mem_init(void)
203 return 0;
206 static void __exit alsa_util_mem_exit(void)
210 module_init(alsa_util_mem_init)
211 module_exit(alsa_util_mem_exit)