diff options
Diffstat (limited to 'lib/genalloc.c')
| -rw-r--r-- | lib/genalloc.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/lib/genalloc.c b/lib/genalloc.c new file mode 100644 index 000000000000..d6d30d2e7166 --- /dev/null +++ b/lib/genalloc.c @@ -0,0 +1,188 @@ +/* + * Basic general purpose allocator for managing special purpose memory + * not managed by the regular kmalloc/kfree interface. + * Uses for this includes on-device special memory, uncached memory + * etc. + * + * This code is based on the buddy allocator found in the sym53c8xx_2 + * driver Copyright (C) 1999-2001 Gerard Roudier <groudier@free.fr>, + * and adapted for general purpose use. + * + * Copyright 2005 (C) Jes Sorensen <jes@trained-monkey.org> + * + * This source code is licensed under the GNU General Public License, + * Version 2. See the file COPYING for more details. + */ + +#include <linux/module.h> +#include <linux/stddef.h> +#include <linux/kernel.h> +#include <linux/string.h> +#include <linux/slab.h> +#include <linux/init.h> +#include <linux/mm.h> +#include <linux/spinlock.h> +#include <linux/genalloc.h> + +#include <asm/page.h> + + +struct gen_pool *gen_pool_create(int nr_chunks, int max_chunk_shift, + unsigned long (*fp)(struct gen_pool *), + unsigned long data) +{ + struct gen_pool *poolp; + unsigned long tmp; + int i; + + /* + * This is really an arbitrary limit, +10 is enough for + * IA64_GRANULE_SHIFT, aka 16MB. If anyone needs a large limit + * this can be increased without problems. + */ + if ((max_chunk_shift > (PAGE_SHIFT + 10)) || + ((max_chunk_shift < ALLOC_MIN_SHIFT) && max_chunk_shift)) + return NULL; + + if (!max_chunk_shift) + max_chunk_shift = PAGE_SHIFT; + + poolp = kmalloc(sizeof(struct gen_pool), GFP_KERNEL); + if (!poolp) + return NULL; + memset(poolp, 0, sizeof(struct gen_pool)); + poolp->h = kmalloc(sizeof(struct gen_pool_link) * + (max_chunk_shift - ALLOC_MIN_SHIFT + 1), + GFP_KERNEL); + if (!poolp->h) { + printk(KERN_WARNING "gen_pool_alloc() failed to allocate\n"); + kfree(poolp); + return NULL; + } + memset(poolp->h, 0, sizeof(struct gen_pool_link) * + (max_chunk_shift - ALLOC_MIN_SHIFT + 1)); + + spin_lock_init(&poolp->lock); + poolp->get_new_chunk = fp; + poolp->max_chunk_shift = max_chunk_shift; + poolp->private = data; + + for (i = 0; i < nr_chunks; i++) { + tmp = poolp->get_new_chunk(poolp); + printk(KERN_INFO "allocated %lx\n", tmp); + if (!tmp) + break; + gen_pool_free(poolp, tmp, (1 << poolp->max_chunk_shift)); + } + + return poolp; +} +EXPORT_SYMBOL(gen_pool_create); + + +/* + * Simple power of two buddy-like generic allocator. + * Provides naturally aligned memory chunks. + */ +unsigned long gen_pool_alloc(struct gen_pool *poolp, int size) +{ + int j, i, s, max_chunk_size; + unsigned long a, flags; + struct gen_pool_link *h = poolp->h; + + max_chunk_size = 1 << poolp->max_chunk_shift; + + if (size > max_chunk_size) + return 0; + + i = 0; + + size = max(size, 1 << ALLOC_MIN_SHIFT); + s = roundup_pow_of_two(size); + + j = i; + + spin_lock_irqsave(&poolp->lock, flags); + while (!h[j].next) { + if (s == max_chunk_size) { + struct gen_pool_link *ptr; + spin_unlock_irqrestore(&poolp->lock, flags); + ptr = (struct gen_pool_link *)poolp->get_new_chunk(poolp); + spin_lock_irqsave(&poolp->lock, flags); + h[j].next = ptr; + if (h[j].next) + h[j].next->next = NULL; + break; + } + j++; + s <<= 1; + } + a = (unsigned long) h[j].next; + if (a) { + h[j].next = h[j].next->next; + /* + * This should be split into a seperate function doing + * the chunk split in order to support custom + * handling memory not physically accessible by host + */ + while (j > i) { + j -= 1; + s >>= 1; + h[j].next = (struct gen_pool_link *) (a + s); + h[j].next->next = NULL; + } + } + spin_unlock_irqrestore(&poolp->lock, flags); + return a; +} +EXPORT_SYMBOL(gen_pool_alloc); + + +/* + * Counter-part of the generic allocator. + */ +void gen_pool_free(struct gen_pool *poolp, unsigned long ptr, int size) +{ + struct gen_pool_link *q; + struct gen_pool_link *h = poolp->h; + unsigned long a, b, flags; + int i, s, max_chunk_size; + + max_chunk_size = 1 << poolp->max_chunk_shift; + + if (size > max_chunk_size) + return; + + i = 0; + + size = max(size, 1 << ALLOC_MIN_SHIFT); + s = roundup_pow_of_two(size); + + a = ptr; + + spin_lock_irqsave(&poolp->lock, flags); + while (1) { + if (s == max_chunk_size) { + ((struct gen_pool_link *)a)->next = h[i].next; + h[i].next = (struct gen_pool_link *)a; + break; + } + b = a ^ s; + q = &h[i]; + + while (q->next && q->next != (struct gen_pool_link *)b) + q = q->next; + + if (!q->next) { + ((struct gen_pool_link *)a)->next = h[i].next; + h[i].next = (struct gen_pool_link *)a; + break; + } + q->next = q->next->next; + a = a & b; + s <<= 1; + i++; + } + spin_unlock_irqrestore(&poolp->lock, flags); +} +EXPORT_SYMBOL(gen_pool_free); |