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(size: 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(list: &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(entry: p); |
51 | kfree(get_memblk(p)); |
52 | } |
53 | kfree(objp: 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, prev: 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(size: 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(new: &blk->list, head: 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(lock: &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(entry: &blk->list); |
143 | hdr->nblocks--; |
144 | hdr->used -= blk->size; |
145 | kfree(objp: 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(lock: &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(lock: &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 | |