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f14f75b8 JS |
1 | /* |
2 | * Basic general purpose allocator for managing special purpose memory | |
3 | * not managed by the regular kmalloc/kfree interface. | |
4 | * Uses for this includes on-device special memory, uncached memory | |
5 | * etc. | |
6 | * | |
7 | * This code is based on the buddy allocator found in the sym53c8xx_2 | |
8 | * driver Copyright (C) 1999-2001 Gerard Roudier <groudier@free.fr>, | |
9 | * and adapted for general purpose use. | |
10 | * | |
11 | * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org> | |
12 | * | |
13 | * This source code is licensed under the GNU General Public License, | |
14 | * Version 2. See the file COPYING for more details. | |
15 | */ | |
16 | ||
17 | #include <linux/module.h> | |
18 | #include <linux/stddef.h> | |
19 | #include <linux/kernel.h> | |
20 | #include <linux/string.h> | |
21 | #include <linux/slab.h> | |
22 | #include <linux/init.h> | |
23 | #include <linux/mm.h> | |
24 | #include <linux/spinlock.h> | |
25 | #include <linux/genalloc.h> | |
26 | ||
27 | #include <asm/page.h> | |
28 | ||
29 | ||
30 | struct gen_pool *gen_pool_create(int nr_chunks, int max_chunk_shift, | |
31 | unsigned long (*fp)(struct gen_pool *), | |
32 | unsigned long data) | |
33 | { | |
34 | struct gen_pool *poolp; | |
35 | unsigned long tmp; | |
36 | int i; | |
37 | ||
38 | /* | |
39 | * This is really an arbitrary limit, +10 is enough for | |
40 | * IA64_GRANULE_SHIFT, aka 16MB. If anyone needs a large limit | |
41 | * this can be increased without problems. | |
42 | */ | |
43 | if ((max_chunk_shift > (PAGE_SHIFT + 10)) || | |
44 | ((max_chunk_shift < ALLOC_MIN_SHIFT) && max_chunk_shift)) | |
45 | return NULL; | |
46 | ||
47 | if (!max_chunk_shift) | |
48 | max_chunk_shift = PAGE_SHIFT; | |
49 | ||
50 | poolp = kmalloc(sizeof(struct gen_pool), GFP_KERNEL); | |
51 | if (!poolp) | |
52 | return NULL; | |
53 | memset(poolp, 0, sizeof(struct gen_pool)); | |
54 | poolp->h = kmalloc(sizeof(struct gen_pool_link) * | |
55 | (max_chunk_shift - ALLOC_MIN_SHIFT + 1), | |
56 | GFP_KERNEL); | |
57 | if (!poolp->h) { | |
58 | printk(KERN_WARNING "gen_pool_alloc() failed to allocate\n"); | |
59 | kfree(poolp); | |
60 | return NULL; | |
61 | } | |
62 | memset(poolp->h, 0, sizeof(struct gen_pool_link) * | |
63 | (max_chunk_shift - ALLOC_MIN_SHIFT + 1)); | |
64 | ||
65 | spin_lock_init(&poolp->lock); | |
66 | poolp->get_new_chunk = fp; | |
67 | poolp->max_chunk_shift = max_chunk_shift; | |
68 | poolp->private = data; | |
69 | ||
70 | for (i = 0; i < nr_chunks; i++) { | |
71 | tmp = poolp->get_new_chunk(poolp); | |
72 | printk(KERN_INFO "allocated %lx\n", tmp); | |
73 | if (!tmp) | |
74 | break; | |
75 | gen_pool_free(poolp, tmp, (1 << poolp->max_chunk_shift)); | |
76 | } | |
77 | ||
78 | return poolp; | |
79 | } | |
80 | EXPORT_SYMBOL(gen_pool_create); | |
81 | ||
82 | ||
83 | /* | |
84 | * Simple power of two buddy-like generic allocator. | |
85 | * Provides naturally aligned memory chunks. | |
86 | */ | |
87 | unsigned long gen_pool_alloc(struct gen_pool *poolp, int size) | |
88 | { | |
89 | int j, i, s, max_chunk_size; | |
90 | unsigned long a, flags; | |
91 | struct gen_pool_link *h = poolp->h; | |
92 | ||
93 | max_chunk_size = 1 << poolp->max_chunk_shift; | |
94 | ||
95 | if (size > max_chunk_size) | |
96 | return 0; | |
97 | ||
98 | i = 0; | |
99 | ||
100 | size = max(size, 1 << ALLOC_MIN_SHIFT); | |
101 | s = roundup_pow_of_two(size); | |
102 | ||
103 | j = i; | |
104 | ||
105 | spin_lock_irqsave(&poolp->lock, flags); | |
106 | while (!h[j].next) { | |
107 | if (s == max_chunk_size) { | |
108 | struct gen_pool_link *ptr; | |
109 | spin_unlock_irqrestore(&poolp->lock, flags); | |
110 | ptr = (struct gen_pool_link *)poolp->get_new_chunk(poolp); | |
111 | spin_lock_irqsave(&poolp->lock, flags); | |
112 | h[j].next = ptr; | |
113 | if (h[j].next) | |
114 | h[j].next->next = NULL; | |
115 | break; | |
116 | } | |
117 | j++; | |
118 | s <<= 1; | |
119 | } | |
120 | a = (unsigned long) h[j].next; | |
121 | if (a) { | |
122 | h[j].next = h[j].next->next; | |
123 | /* | |
124 | * This should be split into a seperate function doing | |
125 | * the chunk split in order to support custom | |
126 | * handling memory not physically accessible by host | |
127 | */ | |
128 | while (j > i) { | |
129 | j -= 1; | |
130 | s >>= 1; | |
131 | h[j].next = (struct gen_pool_link *) (a + s); | |
132 | h[j].next->next = NULL; | |
133 | } | |
134 | } | |
135 | spin_unlock_irqrestore(&poolp->lock, flags); | |
136 | return a; | |
137 | } | |
138 | EXPORT_SYMBOL(gen_pool_alloc); | |
139 | ||
140 | ||
141 | /* | |
142 | * Counter-part of the generic allocator. | |
143 | */ | |
144 | void gen_pool_free(struct gen_pool *poolp, unsigned long ptr, int size) | |
145 | { | |
146 | struct gen_pool_link *q; | |
147 | struct gen_pool_link *h = poolp->h; | |
148 | unsigned long a, b, flags; | |
149 | int i, s, max_chunk_size; | |
150 | ||
151 | max_chunk_size = 1 << poolp->max_chunk_shift; | |
152 | ||
153 | if (size > max_chunk_size) | |
154 | return; | |
155 | ||
156 | i = 0; | |
157 | ||
158 | size = max(size, 1 << ALLOC_MIN_SHIFT); | |
159 | s = roundup_pow_of_two(size); | |
160 | ||
161 | a = ptr; | |
162 | ||
163 | spin_lock_irqsave(&poolp->lock, flags); | |
164 | while (1) { | |
165 | if (s == max_chunk_size) { | |
166 | ((struct gen_pool_link *)a)->next = h[i].next; | |
167 | h[i].next = (struct gen_pool_link *)a; | |
168 | break; | |
169 | } | |
170 | b = a ^ s; | |
171 | q = &h[i]; | |
172 | ||
173 | while (q->next && q->next != (struct gen_pool_link *)b) | |
174 | q = q->next; | |
175 | ||
176 | if (!q->next) { | |
177 | ((struct gen_pool_link *)a)->next = h[i].next; | |
178 | h[i].next = (struct gen_pool_link *)a; | |
179 | break; | |
180 | } | |
181 | q->next = q->next->next; | |
182 | a = a & b; | |
183 | s <<= 1; | |
184 | i++; | |
185 | } | |
186 | spin_unlock_irqrestore(&poolp->lock, flags); | |
187 | } | |
188 | EXPORT_SYMBOL(gen_pool_free); |