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git.proxmox.com Git - mirror_ubuntu-zesty-kernel.git/blob - lib/genalloc.c
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
7 * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
9 * This source code is licensed under the GNU General Public License,
10 * Version 2. See the file COPYING for more details.
13 #include <linux/module.h>
14 #include <linux/genalloc.h>
18 * Create a new special memory pool.
20 * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
21 * @nid: node id of the node the pool structure should be allocated on, or -1
23 struct gen_pool
*gen_pool_create(int min_alloc_order
, int nid
)
25 struct gen_pool
*pool
;
27 pool
= kmalloc_node(sizeof(struct gen_pool
), GFP_KERNEL
, nid
);
29 rwlock_init(&pool
->lock
);
30 INIT_LIST_HEAD(&pool
->chunks
);
31 pool
->min_alloc_order
= min_alloc_order
;
35 EXPORT_SYMBOL(gen_pool_create
);
39 * Add a new chunk of memory to the specified pool.
41 * @pool: pool to add new memory chunk to
42 * @addr: starting address of memory chunk to add to pool
43 * @size: size in bytes of the memory chunk to add to pool
44 * @nid: node id of the node the chunk structure and bitmap should be
47 int gen_pool_add(struct gen_pool
*pool
, unsigned long addr
, size_t size
,
50 struct gen_pool_chunk
*chunk
;
51 int nbits
= size
>> pool
->min_alloc_order
;
52 int nbytes
= sizeof(struct gen_pool_chunk
) +
53 (nbits
+ BITS_PER_BYTE
- 1) / BITS_PER_BYTE
;
55 chunk
= kmalloc_node(nbytes
, GFP_KERNEL
, nid
);
56 if (unlikely(chunk
== NULL
))
59 memset(chunk
, 0, nbytes
);
60 spin_lock_init(&chunk
->lock
);
61 chunk
->start_addr
= addr
;
62 chunk
->end_addr
= addr
+ size
;
64 write_lock(&pool
->lock
);
65 list_add(&chunk
->next_chunk
, &pool
->chunks
);
66 write_unlock(&pool
->lock
);
70 EXPORT_SYMBOL(gen_pool_add
);
74 * Allocate the requested number of bytes from the specified pool.
75 * Uses a first-fit algorithm.
77 * @pool: pool to allocate from
78 * @size: number of bytes to allocate from the pool
80 unsigned long gen_pool_alloc(struct gen_pool
*pool
, size_t size
)
82 struct list_head
*_chunk
;
83 struct gen_pool_chunk
*chunk
;
84 unsigned long addr
, flags
;
85 int order
= pool
->min_alloc_order
;
86 int nbits
, bit
, start_bit
, end_bit
;
91 nbits
= (size
+ (1UL << order
) - 1) >> order
;
93 read_lock(&pool
->lock
);
94 list_for_each(_chunk
, &pool
->chunks
) {
95 chunk
= list_entry(_chunk
, struct gen_pool_chunk
, next_chunk
);
97 end_bit
= (chunk
->end_addr
- chunk
->start_addr
) >> order
;
100 spin_lock_irqsave(&chunk
->lock
, flags
);
102 while (bit
+ 1 < end_bit
) {
103 bit
= find_next_zero_bit(chunk
->bits
, end_bit
, bit
+ 1);
109 bit
= find_next_bit(chunk
->bits
, bit
+ nbits
,
111 if (bit
- start_bit
< nbits
)
115 addr
= chunk
->start_addr
+
116 ((unsigned long)start_bit
<< order
);
118 __set_bit(start_bit
++, &chunk
->bits
);
119 spin_unlock_irqrestore(&chunk
->lock
, flags
);
120 read_unlock(&pool
->lock
);
123 spin_unlock_irqrestore(&chunk
->lock
, flags
);
125 read_unlock(&pool
->lock
);
128 EXPORT_SYMBOL(gen_pool_alloc
);
132 * Free the specified memory back to the specified pool.
134 * @pool: pool to free to
135 * @addr: starting address of memory to free back to pool
136 * @size: size in bytes of memory to free
138 void gen_pool_free(struct gen_pool
*pool
, unsigned long addr
, size_t size
)
140 struct list_head
*_chunk
;
141 struct gen_pool_chunk
*chunk
;
143 int order
= pool
->min_alloc_order
;
146 nbits
= (size
+ (1UL << order
) - 1) >> order
;
148 read_lock(&pool
->lock
);
149 list_for_each(_chunk
, &pool
->chunks
) {
150 chunk
= list_entry(_chunk
, struct gen_pool_chunk
, next_chunk
);
152 if (addr
>= chunk
->start_addr
&& addr
< chunk
->end_addr
) {
153 BUG_ON(addr
+ size
> chunk
->end_addr
);
154 spin_lock_irqsave(&chunk
->lock
, flags
);
155 bit
= (addr
- chunk
->start_addr
) >> order
;
157 __clear_bit(bit
++, &chunk
->bits
);
158 spin_unlock_irqrestore(&chunk
->lock
, flags
);
163 read_unlock(&pool
->lock
);
165 EXPORT_SYMBOL(gen_pool_free
);