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Jes Sorensenf14f75b2005-06-21 17:15:02 -07001/*
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 *
Jes Sorensenf14f75b2005-06-21 17:15:02 -07007 * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org>
8 *
9 * This source code is licensed under the GNU General Public License,
10 * Version 2. See the file COPYING for more details.
11 */
12
13#include <linux/module.h>
Akinobu Mita243797f2009-12-15 16:48:31 -080014#include <linux/bitmap.h>
Jes Sorensenf14f75b2005-06-21 17:15:02 -070015#include <linux/genalloc.h>
16
Jes Sorensenf14f75b2005-06-21 17:15:02 -070017
Dean Nelsona58cbd72006-10-02 02:17:01 -070018/**
19 * gen_pool_create - create a new special memory pool
Dean Nelson929f9722006-06-23 02:03:21 -070020 * @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
Dean Nelsona58cbd72006-10-02 02:17:01 -070022 *
23 * Create a new special memory pool that can be used to manage special purpose
24 * memory not managed by the regular kmalloc/kfree interface.
Dean Nelson929f9722006-06-23 02:03:21 -070025 */
26struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
Jes Sorensenf14f75b2005-06-21 17:15:02 -070027{
Dean Nelson929f9722006-06-23 02:03:21 -070028 struct gen_pool *pool;
Jes Sorensenf14f75b2005-06-21 17:15:02 -070029
Dean Nelson929f9722006-06-23 02:03:21 -070030 pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
31 if (pool != NULL) {
32 rwlock_init(&pool->lock);
33 INIT_LIST_HEAD(&pool->chunks);
34 pool->min_alloc_order = min_alloc_order;
Jes Sorensenf14f75b2005-06-21 17:15:02 -070035 }
Dean Nelson929f9722006-06-23 02:03:21 -070036 return pool;
Jes Sorensenf14f75b2005-06-21 17:15:02 -070037}
38EXPORT_SYMBOL(gen_pool_create);
39
Dean Nelsona58cbd72006-10-02 02:17:01 -070040/**
41 * gen_pool_add - add a new chunk of special memory to the pool
Dean Nelson929f9722006-06-23 02:03:21 -070042 * @pool: pool to add new memory chunk to
43 * @addr: starting address of memory chunk to add to pool
44 * @size: size in bytes of the memory chunk to add to pool
45 * @nid: node id of the node the chunk structure and bitmap should be
46 * allocated on, or -1
Dean Nelsona58cbd72006-10-02 02:17:01 -070047 *
48 * Add a new chunk of special memory to the specified pool.
Jes Sorensenf14f75b2005-06-21 17:15:02 -070049 */
Dean Nelson929f9722006-06-23 02:03:21 -070050int gen_pool_add(struct gen_pool *pool, unsigned long addr, size_t size,
51 int nid)
Jes Sorensenf14f75b2005-06-21 17:15:02 -070052{
Dean Nelson929f9722006-06-23 02:03:21 -070053 struct gen_pool_chunk *chunk;
54 int nbits = size >> pool->min_alloc_order;
55 int nbytes = sizeof(struct gen_pool_chunk) +
56 (nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
Jes Sorensenf14f75b2005-06-21 17:15:02 -070057
Christoph Lameter94f60302007-07-17 04:03:29 -070058 chunk = kmalloc_node(nbytes, GFP_KERNEL | __GFP_ZERO, nid);
Dean Nelson929f9722006-06-23 02:03:21 -070059 if (unlikely(chunk == NULL))
60 return -1;
Jes Sorensenf14f75b2005-06-21 17:15:02 -070061
Dean Nelson929f9722006-06-23 02:03:21 -070062 spin_lock_init(&chunk->lock);
63 chunk->start_addr = addr;
64 chunk->end_addr = addr + size;
65
66 write_lock(&pool->lock);
67 list_add(&chunk->next_chunk, &pool->chunks);
68 write_unlock(&pool->lock);
69
70 return 0;
71}
72EXPORT_SYMBOL(gen_pool_add);
73
Dean Nelsona58cbd72006-10-02 02:17:01 -070074/**
75 * gen_pool_destroy - destroy a special memory pool
Steve Wise322acc92006-10-02 02:17:00 -070076 * @pool: pool to destroy
Dean Nelsona58cbd72006-10-02 02:17:01 -070077 *
78 * Destroy the specified special memory pool. Verifies that there are no
79 * outstanding allocations.
Steve Wise322acc92006-10-02 02:17:00 -070080 */
81void gen_pool_destroy(struct gen_pool *pool)
82{
83 struct list_head *_chunk, *_next_chunk;
84 struct gen_pool_chunk *chunk;
85 int order = pool->min_alloc_order;
86 int bit, end_bit;
87
88
Steve Wise322acc92006-10-02 02:17:00 -070089 list_for_each_safe(_chunk, _next_chunk, &pool->chunks) {
90 chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
91 list_del(&chunk->next_chunk);
92
93 end_bit = (chunk->end_addr - chunk->start_addr) >> order;
94 bit = find_next_bit(chunk->bits, end_bit, 0);
95 BUG_ON(bit < end_bit);
96
97 kfree(chunk);
98 }
99 kfree(pool);
100 return;
101}
102EXPORT_SYMBOL(gen_pool_destroy);
103
Dean Nelsona58cbd72006-10-02 02:17:01 -0700104/**
105 * gen_pool_alloc - allocate special memory from the pool
Dean Nelson929f9722006-06-23 02:03:21 -0700106 * @pool: pool to allocate from
107 * @size: number of bytes to allocate from the pool
Dean Nelsona58cbd72006-10-02 02:17:01 -0700108 *
109 * Allocate the requested number of bytes from the specified pool.
110 * Uses a first-fit algorithm.
Dean Nelson929f9722006-06-23 02:03:21 -0700111 */
112unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
113{
114 struct list_head *_chunk;
115 struct gen_pool_chunk *chunk;
116 unsigned long addr, flags;
117 int order = pool->min_alloc_order;
Akinobu Mita243797f2009-12-15 16:48:31 -0800118 int nbits, start_bit, end_bit;
Dean Nelson929f9722006-06-23 02:03:21 -0700119
120 if (size == 0)
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700121 return 0;
122
Dean Nelson929f9722006-06-23 02:03:21 -0700123 nbits = (size + (1UL << order) - 1) >> order;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700124
Dean Nelson929f9722006-06-23 02:03:21 -0700125 read_lock(&pool->lock);
126 list_for_each(_chunk, &pool->chunks) {
127 chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
128
129 end_bit = (chunk->end_addr - chunk->start_addr) >> order;
130 end_bit -= nbits + 1;
131
132 spin_lock_irqsave(&chunk->lock, flags);
Akinobu Mita243797f2009-12-15 16:48:31 -0800133 start_bit = bitmap_find_next_zero_area(chunk->bits, end_bit, 0,
134 nbits, 0);
135 if (start_bit >= end_bit) {
Dean Nelson929f9722006-06-23 02:03:21 -0700136 spin_unlock_irqrestore(&chunk->lock, flags);
Akinobu Mita243797f2009-12-15 16:48:31 -0800137 continue;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700138 }
Akinobu Mita243797f2009-12-15 16:48:31 -0800139
140 addr = chunk->start_addr + ((unsigned long)start_bit << order);
141
142 bitmap_set(chunk->bits, start_bit, nbits);
Dean Nelson929f9722006-06-23 02:03:21 -0700143 spin_unlock_irqrestore(&chunk->lock, flags);
Akinobu Mita243797f2009-12-15 16:48:31 -0800144 read_unlock(&pool->lock);
145 return addr;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700146 }
Dean Nelson929f9722006-06-23 02:03:21 -0700147 read_unlock(&pool->lock);
148 return 0;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700149}
150EXPORT_SYMBOL(gen_pool_alloc);
151
Dean Nelsona58cbd72006-10-02 02:17:01 -0700152/**
153 * gen_pool_free - free allocated special memory back to the pool
Dean Nelson929f9722006-06-23 02:03:21 -0700154 * @pool: pool to free to
155 * @addr: starting address of memory to free back to pool
156 * @size: size in bytes of memory to free
Dean Nelsona58cbd72006-10-02 02:17:01 -0700157 *
158 * Free previously allocated special memory back to the specified pool.
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700159 */
Dean Nelson929f9722006-06-23 02:03:21 -0700160void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700161{
Dean Nelson929f9722006-06-23 02:03:21 -0700162 struct list_head *_chunk;
163 struct gen_pool_chunk *chunk;
164 unsigned long flags;
165 int order = pool->min_alloc_order;
166 int bit, nbits;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700167
Dean Nelson929f9722006-06-23 02:03:21 -0700168 nbits = (size + (1UL << order) - 1) >> order;
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700169
Dean Nelson929f9722006-06-23 02:03:21 -0700170 read_lock(&pool->lock);
171 list_for_each(_chunk, &pool->chunks) {
172 chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700173
Dean Nelson929f9722006-06-23 02:03:21 -0700174 if (addr >= chunk->start_addr && addr < chunk->end_addr) {
175 BUG_ON(addr + size > chunk->end_addr);
176 spin_lock_irqsave(&chunk->lock, flags);
177 bit = (addr - chunk->start_addr) >> order;
178 while (nbits--)
Andrew Morton96c62d52007-02-20 13:58:12 -0800179 __clear_bit(bit++, chunk->bits);
Dean Nelson929f9722006-06-23 02:03:21 -0700180 spin_unlock_irqrestore(&chunk->lock, flags);
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700181 break;
182 }
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700183 }
Dean Nelson929f9722006-06-23 02:03:21 -0700184 BUG_ON(nbits > 0);
185 read_unlock(&pool->lock);
Jes Sorensenf14f75b2005-06-21 17:15:02 -0700186}
187EXPORT_SYMBOL(gen_pool_free);