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/*
* 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;
size = max(size, 1 << ALLOC_MIN_SHIFT);
i = fls(size - 1);
s = 1 << i;
j = i -= ALLOC_MIN_SHIFT;
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;
size = max(size, 1 << ALLOC_MIN_SHIFT);
i = fls(size - 1);
s = 1 << i;
i -= ALLOC_MIN_SHIFT;
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);
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