1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2000 Takashi Iwai <tiwai@suse.de>
4 *
5 * Generic memory management routines for soundcard memory allocation
6 */
7
8 #include <linux/mutex.h>
9 #include <linux/init.h>
10 #include <linux/slab.h>
11 #include <linux/module.h>
12 #include <sound/core.h>
13 #include <sound/util_mem.h>
14
15 MODULE_AUTHOR("Takashi Iwai");
16 MODULE_DESCRIPTION("Generic memory management routines for soundcard memory allocation");
17 MODULE_LICENSE("GPL");
18
19 #define get_memblk(p) list_entry(p, struct snd_util_memblk, list)
20
21 /*
22 * create a new memory manager
23 */
24 struct snd_util_memhdr *
25 snd_util_memhdr_new(int memsize)
26 {
27 struct snd_util_memhdr *hdr;
28
29 hdr = kzalloc(sizeof(*hdr), GFP_KERNEL);
30 if (hdr == NULL)
31 return NULL;
32 hdr->size = memsize;
33 mutex_init(&hdr->block_mutex);
34 INIT_LIST_HEAD(&hdr->block);
35
36 return hdr;
37 }
38
39 /*
40 * free a memory manager
41 */
42 void snd_util_memhdr_free(struct snd_util_memhdr *hdr)
43 {
44 struct list_head *p;
45
46 if (!hdr)
47 return;
48 /* release all blocks */
49 while ((p = hdr->block.next) != &hdr->block) {
50 list_del(p);
51 kfree(get_memblk(p));
52 }
53 kfree(hdr);
54 }
55
56 /*
57 * allocate a memory block (without mutex)
58 */
59 struct snd_util_memblk *
60 __snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
61 {
62 struct snd_util_memblk *blk;
63 unsigned int units, prev_offset;
64 struct list_head *p;
65
66 if (snd_BUG_ON(!hdr || size <= 0))
67 return NULL;
68
69 /* word alignment */
70 units = size;
71 if (units & 1)
72 units++;
73 if (units > hdr->size)
74 return NULL;
75
76 /* look for empty block */
77 prev_offset = 0;
78 list_for_each(p, &hdr->block) {
79 blk = get_memblk(p);
80 if (blk->offset - prev_offset >= units)
81 goto __found;
82 prev_offset = blk->offset + blk->size;
83 }
84 if (hdr->size - prev_offset < units)
85 return NULL;
86
87 __found:
88 return __snd_util_memblk_new(hdr, units, p->prev);
89 }
90
91
92 /*
93 * create a new memory block with the given size
94 * the block is linked next to prev
95 */
96 struct snd_util_memblk *
97 __snd_util_memblk_new(struct snd_util_memhdr *hdr, unsigned int units,
98 struct list_head *prev)
99 {
100 struct snd_util_memblk *blk;
101
102 blk = kmalloc(sizeof(struct snd_util_memblk) + hdr->block_extra_size,
103 GFP_KERNEL);
104 if (blk == NULL)
105 return NULL;
106
107 if (prev == &hdr->block)
108 blk->offset = 0;
109 else {
110 struct snd_util_memblk *p = get_memblk(prev);
111 blk->offset = p->offset + p->size;
112 }
113 blk->size = units;
114 list_add(&blk->list, prev);
115 hdr->nblocks++;
116 hdr->used += units;
117 return blk;
118 }
119
120
121 /*
122 * allocate a memory block (with mutex)
123 */
124 struct snd_util_memblk *
125 snd_util_mem_alloc(struct snd_util_memhdr *hdr, int size)
126 {
127 struct snd_util_memblk *blk;
128 mutex_lock(&hdr->block_mutex);
129 blk = __snd_util_mem_alloc(hdr, size);
130 mutex_unlock(&hdr->block_mutex);
131 return blk;
132 }
133
134
135 /*
136 * remove the block from linked-list and free resource
137 * (without mutex)
138 */
139 void
140 __snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
141 {
142 list_del(&blk->list);
143 hdr->nblocks--;
144 hdr->used -= blk->size;
145 kfree(blk);
146 }
147
148 /*
149 * free a memory block (with mutex)
150 */
151 int snd_util_mem_free(struct snd_util_memhdr *hdr, struct snd_util_memblk *blk)
152 {
153 if (snd_BUG_ON(!hdr || !blk))
154 return -EINVAL;
155
156 mutex_lock(&hdr->block_mutex);
157 __snd_util_mem_free(hdr, blk);
158 mutex_unlock(&hdr->block_mutex);
159 return 0;
160 }
161
162 /*
163 * return available memory size
164 */
165 int snd_util_mem_avail(struct snd_util_memhdr *hdr)
166 {
167 unsigned int size;
168 mutex_lock(&hdr->block_mutex);
169 size = hdr->size - hdr->used;
170 mutex_unlock(&hdr->block_mutex);
171 return size;
172 }
173
174
175 EXPORT_SYMBOL(snd_util_memhdr_new);
176 EXPORT_SYMBOL(snd_util_memhdr_free);
177 EXPORT_SYMBOL(snd_util_mem_alloc);
178 EXPORT_SYMBOL(snd_util_mem_free);
179 EXPORT_SYMBOL(snd_util_mem_avail);
180 EXPORT_SYMBOL(__snd_util_mem_alloc);
181 EXPORT_SYMBOL(__snd_util_mem_free);
182 EXPORT_SYMBOL(__snd_util_memblk_new);
183
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.