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git.proxmox.com Git - mirror_ubuntu-eoan-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/slab.h>
14 #include <linux/module.h>
15 #include <linux/bitmap.h>
16 #include <linux/genalloc.h>
20 * gen_pool_create - create a new special memory pool
21 * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
22 * @nid: node id of the node the pool structure should be allocated on, or -1
24 * Create a new special memory pool that can be used to manage special purpose
25 * memory not managed by the regular kmalloc/kfree interface.
27 struct gen_pool
*gen_pool_create(int min_alloc_order
, int nid
)
29 struct gen_pool
*pool
;
31 pool
= kmalloc_node(sizeof(struct gen_pool
), GFP_KERNEL
, nid
);
33 rwlock_init(&pool
->lock
);
34 INIT_LIST_HEAD(&pool
->chunks
);
35 pool
->min_alloc_order
= min_alloc_order
;
39 EXPORT_SYMBOL(gen_pool_create
);
42 * gen_pool_add_virt - add a new chunk of special memory to the pool
43 * @pool: pool to add new memory chunk to
44 * @virt: virtual starting address of memory chunk to add to pool
45 * @phys: physical starting address of memory chunk to add to pool
46 * @size: size in bytes of the memory chunk to add to pool
47 * @nid: node id of the node the chunk structure and bitmap should be
50 * Add a new chunk of special memory to the specified pool.
52 * Returns 0 on success or a -ve errno on failure.
54 int gen_pool_add_virt(struct gen_pool
*pool
, unsigned long virt
, phys_addr_t phys
,
57 struct gen_pool_chunk
*chunk
;
58 int nbits
= size
>> pool
->min_alloc_order
;
59 int nbytes
= sizeof(struct gen_pool_chunk
) +
60 (nbits
+ BITS_PER_BYTE
- 1) / BITS_PER_BYTE
;
62 chunk
= kmalloc_node(nbytes
, GFP_KERNEL
| __GFP_ZERO
, nid
);
63 if (unlikely(chunk
== NULL
))
66 spin_lock_init(&chunk
->lock
);
67 chunk
->phys_addr
= phys
;
68 chunk
->start_addr
= virt
;
69 chunk
->end_addr
= virt
+ size
;
71 write_lock(&pool
->lock
);
72 list_add(&chunk
->next_chunk
, &pool
->chunks
);
73 write_unlock(&pool
->lock
);
77 EXPORT_SYMBOL(gen_pool_add_virt
);
80 * gen_pool_virt_to_phys - return the physical address of memory
81 * @pool: pool to allocate from
82 * @addr: starting address of memory
84 * Returns the physical address on success, or -1 on error.
86 phys_addr_t
gen_pool_virt_to_phys(struct gen_pool
*pool
, unsigned long addr
)
88 struct list_head
*_chunk
;
89 struct gen_pool_chunk
*chunk
;
91 read_lock(&pool
->lock
);
92 list_for_each(_chunk
, &pool
->chunks
) {
93 chunk
= list_entry(_chunk
, struct gen_pool_chunk
, next_chunk
);
95 if (addr
>= chunk
->start_addr
&& addr
< chunk
->end_addr
)
96 return chunk
->phys_addr
+ addr
- chunk
->start_addr
;
98 read_unlock(&pool
->lock
);
102 EXPORT_SYMBOL(gen_pool_virt_to_phys
);
105 * gen_pool_destroy - destroy a special memory pool
106 * @pool: pool to destroy
108 * Destroy the specified special memory pool. Verifies that there are no
109 * outstanding allocations.
111 void gen_pool_destroy(struct gen_pool
*pool
)
113 struct list_head
*_chunk
, *_next_chunk
;
114 struct gen_pool_chunk
*chunk
;
115 int order
= pool
->min_alloc_order
;
119 list_for_each_safe(_chunk
, _next_chunk
, &pool
->chunks
) {
120 chunk
= list_entry(_chunk
, struct gen_pool_chunk
, next_chunk
);
121 list_del(&chunk
->next_chunk
);
123 end_bit
= (chunk
->end_addr
- chunk
->start_addr
) >> order
;
124 bit
= find_next_bit(chunk
->bits
, end_bit
, 0);
125 BUG_ON(bit
< end_bit
);
132 EXPORT_SYMBOL(gen_pool_destroy
);
135 * gen_pool_alloc - allocate special memory from the pool
136 * @pool: pool to allocate from
137 * @size: number of bytes to allocate from the pool
139 * Allocate the requested number of bytes from the specified pool.
140 * Uses a first-fit algorithm.
142 unsigned long gen_pool_alloc(struct gen_pool
*pool
, size_t size
)
144 struct list_head
*_chunk
;
145 struct gen_pool_chunk
*chunk
;
146 unsigned long addr
, flags
;
147 int order
= pool
->min_alloc_order
;
148 int nbits
, start_bit
, end_bit
;
153 nbits
= (size
+ (1UL << order
) - 1) >> order
;
155 read_lock(&pool
->lock
);
156 list_for_each(_chunk
, &pool
->chunks
) {
157 chunk
= list_entry(_chunk
, struct gen_pool_chunk
, next_chunk
);
159 end_bit
= (chunk
->end_addr
- chunk
->start_addr
) >> order
;
161 spin_lock_irqsave(&chunk
->lock
, flags
);
162 start_bit
= bitmap_find_next_zero_area(chunk
->bits
, end_bit
, 0,
164 if (start_bit
>= end_bit
) {
165 spin_unlock_irqrestore(&chunk
->lock
, flags
);
169 addr
= chunk
->start_addr
+ ((unsigned long)start_bit
<< order
);
171 bitmap_set(chunk
->bits
, start_bit
, nbits
);
172 spin_unlock_irqrestore(&chunk
->lock
, flags
);
173 read_unlock(&pool
->lock
);
176 read_unlock(&pool
->lock
);
179 EXPORT_SYMBOL(gen_pool_alloc
);
182 * gen_pool_free - free allocated special memory back to the pool
183 * @pool: pool to free to
184 * @addr: starting address of memory to free back to pool
185 * @size: size in bytes of memory to free
187 * Free previously allocated special memory back to the specified pool.
189 void gen_pool_free(struct gen_pool
*pool
, unsigned long addr
, size_t size
)
191 struct list_head
*_chunk
;
192 struct gen_pool_chunk
*chunk
;
194 int order
= pool
->min_alloc_order
;
197 nbits
= (size
+ (1UL << order
) - 1) >> order
;
199 read_lock(&pool
->lock
);
200 list_for_each(_chunk
, &pool
->chunks
) {
201 chunk
= list_entry(_chunk
, struct gen_pool_chunk
, next_chunk
);
203 if (addr
>= chunk
->start_addr
&& addr
< chunk
->end_addr
) {
204 BUG_ON(addr
+ size
> chunk
->end_addr
);
205 spin_lock_irqsave(&chunk
->lock
, flags
);
206 bit
= (addr
- chunk
->start_addr
) >> order
;
208 __clear_bit(bit
++, chunk
->bits
);
209 spin_unlock_irqrestore(&chunk
->lock
, flags
);
214 read_unlock(&pool
->lock
);
216 EXPORT_SYMBOL(gen_pool_free
);