Showing error 1436

User: Jiri Slaby
Error type: Leaving function in locked state
Error type description: Some lock is not unlocked on all paths of a function, so it is leaked
File location: lib/genalloc.c
Line in file: 100
Project: Linux Kernel
Project version: 2.6.28
Tools: Stanse (1.2)
Entered: 2012-05-21 20:30:05 UTC

Source: 

  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 * 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>
 14#include <linux/genalloc.h>
 15
 16
 17/**
 18 * gen_pool_create - create a new special memory pool
 19 * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
 20 * @nid: node id of the node the pool structure should be allocated on, or -1
 21 *
 22 * Create a new special memory pool that can be used to manage special purpose
 23 * memory not managed by the regular kmalloc/kfree interface.
 24 */
 25struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
 26{
 27        struct gen_pool *pool;
 28
 29        pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
 30        if (pool != NULL) {
 31                rwlock_init(&pool->lock);
 32                INIT_LIST_HEAD(&pool->chunks);
 33                pool->min_alloc_order = min_alloc_order;
 34        }
 35        return pool;
 36}
 37EXPORT_SYMBOL(gen_pool_create);
 38
 39/**
 40 * gen_pool_add - add a new chunk of special memory to the 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
 45 *       allocated on, or -1
 46 *
 47 * Add a new chunk of special memory to the specified pool.
 48 */
 49int gen_pool_add(struct gen_pool *pool, unsigned long addr, size_t size,
 50                 int nid)
 51{
 52        struct gen_pool_chunk *chunk;
 53        int nbits = size >> pool->min_alloc_order;
 54        int nbytes = sizeof(struct gen_pool_chunk) +
 55                                (nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
 56
 57        chunk = kmalloc_node(nbytes, GFP_KERNEL | __GFP_ZERO, nid);
 58        if (unlikely(chunk == NULL))
 59                return -1;
 60
 61        spin_lock_init(&chunk->lock);
 62        chunk->start_addr = addr;
 63        chunk->end_addr = addr + size;
 64
 65        write_lock(&pool->lock);
 66        list_add(&chunk->next_chunk, &pool->chunks);
 67        write_unlock(&pool->lock);
 68
 69        return 0;
 70}
 71EXPORT_SYMBOL(gen_pool_add);
 72
 73/**
 74 * gen_pool_destroy - destroy a special memory pool
 75 * @pool: pool to destroy
 76 *
 77 * Destroy the specified special memory pool. Verifies that there are no
 78 * outstanding allocations.
 79 */
 80void gen_pool_destroy(struct gen_pool *pool)
 81{
 82        struct list_head *_chunk, *_next_chunk;
 83        struct gen_pool_chunk *chunk;
 84        int order = pool->min_alloc_order;
 85        int bit, end_bit;
 86
 87
 88        write_lock(&pool->lock);
 89        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
104/**
105 * gen_pool_alloc - allocate special memory from the pool
106 * @pool: pool to allocate from
107 * @size: number of bytes to allocate from the pool
108 *
109 * Allocate the requested number of bytes from the specified pool.
110 * Uses a first-fit algorithm.
111 */
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;
118        int nbits, bit, start_bit, end_bit;
119
120        if (size == 0)
121                return 0;
122
123        nbits = (size + (1UL << order) - 1) >> order;
124
125        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);
133                bit = -1;
134                while (bit + 1 < end_bit) {
135                        bit = find_next_zero_bit(chunk->bits, end_bit, bit + 1);
136                        if (bit >= end_bit)
137                                break;
138
139                        start_bit = bit;
140                        if (nbits > 1) {
141                                bit = find_next_bit(chunk->bits, bit + nbits,
142                                                        bit + 1);
143                                if (bit - start_bit < nbits)
144                                        continue;
145                        }
146
147                        addr = chunk->start_addr +
148                                            ((unsigned long)start_bit << order);
149                        while (nbits--)
150                                __set_bit(start_bit++, chunk->bits);
151                        spin_unlock_irqrestore(&chunk->lock, flags);
152                        read_unlock(&pool->lock);
153                        return addr;
154                }
155                spin_unlock_irqrestore(&chunk->lock, flags);
156        }
157        read_unlock(&pool->lock);
158        return 0;
159}
160EXPORT_SYMBOL(gen_pool_alloc);
161
162/**
163 * gen_pool_free - free allocated special memory back to the pool
164 * @pool: pool to free to
165 * @addr: starting address of memory to free back to pool
166 * @size: size in bytes of memory to free
167 *
168 * Free previously allocated special memory back to the specified pool.
169 */
170void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
171{
172        struct list_head *_chunk;
173        struct gen_pool_chunk *chunk;
174        unsigned long flags;
175        int order = pool->min_alloc_order;
176        int bit, nbits;
177
178        nbits = (size + (1UL << order) - 1) >> order;
179
180        read_lock(&pool->lock);
181        list_for_each(_chunk, &pool->chunks) {
182                chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
183
184                if (addr >= chunk->start_addr && addr < chunk->end_addr) {
185                        BUG_ON(addr + size > chunk->end_addr);
186                        spin_lock_irqsave(&chunk->lock, flags);
187                        bit = (addr - chunk->start_addr) >> order;
188                        while (nbits--)
189                                __clear_bit(bit++, chunk->bits);
190                        spin_unlock_irqrestore(&chunk->lock, flags);
191                        break;
192                }
193        }
194        BUG_ON(nbits > 0);
195        read_unlock(&pool->lock);
196}
197EXPORT_SYMBOL(gen_pool_free);
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