X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=lib%2Fgenalloc.c;fp=lib%2Fgenalloc.c;h=9ce0a6a3b85ac49d2f160dda9c732ec65698f078;hb=64ba3f394c830ec48a1c31b53dcae312c56f1604;hp=71338b48e88919ab2a668ecf2ff9f1e25a91b0fa;hpb=be1e6109ac94a859551f8e1774eb9a8469fe055c;p=linux-2.6.git

diff --git a/lib/genalloc.c b/lib/genalloc.c
index 71338b48e..9ce0a6a3b 100644
--- a/lib/genalloc.c
+++ b/lib/genalloc.c
@@ -4,6 +4,10 @@
  * 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,
@@ -11,155 +15,172 @@
  */
 
 #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>
 
-/*
- * Create a new special memory pool.
- *
- * @min_alloc_order: log base 2 of number of bytes each bitmap bit represents
- * @nid: node id of the node the pool structure should be allocated on, or -1
- */
-struct gen_pool *gen_pool_create(int min_alloc_order, int nid)
-{
-	struct gen_pool *pool;
 
-	pool = kmalloc_node(sizeof(struct gen_pool), GFP_KERNEL, nid);
-	if (pool != NULL) {
-		rwlock_init(&pool->lock);
-		INIT_LIST_HEAD(&pool->chunks);
-		pool->min_alloc_order = min_alloc_order;
+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 pool;
+
+	return poolp;
 }
 EXPORT_SYMBOL(gen_pool_create);
 
 
 /*
- * Add a new chunk of memory to the specified pool.
- *
- * @pool: pool to add new memory chunk to
- * @addr: starting address of memory chunk to add to pool
- * @size: size in bytes of the memory chunk to add to pool
- * @nid: node id of the node the chunk structure and bitmap should be
- *       allocated on, or -1
+ *  Simple power of two buddy-like generic allocator.
+ *  Provides naturally aligned memory chunks.
  */
-int gen_pool_add(struct gen_pool *pool, unsigned long addr, size_t size,
-		 int nid)
+unsigned long gen_pool_alloc(struct gen_pool *poolp, int size)
 {
-	struct gen_pool_chunk *chunk;
-	int nbits = size >> pool->min_alloc_order;
-	int nbytes = sizeof(struct gen_pool_chunk) +
-				(nbits + BITS_PER_BYTE - 1) / BITS_PER_BYTE;
+	int j, i, s, max_chunk_size;
+	unsigned long a, flags;
+	struct gen_pool_link *h = poolp->h;
 
-	chunk = kmalloc_node(nbytes, GFP_KERNEL, nid);
-	if (unlikely(chunk == NULL))
-		return -1;
+	max_chunk_size = 1 << poolp->max_chunk_shift;
 
-	memset(chunk, 0, nbytes);
-	spin_lock_init(&chunk->lock);
-	chunk->start_addr = addr;
-	chunk->end_addr = addr + size;
-
-	write_lock(&pool->lock);
-	list_add(&chunk->next_chunk, &pool->chunks);
-	write_unlock(&pool->lock);
+	if (size > max_chunk_size)
+		return 0;
 
-	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_add);
+EXPORT_SYMBOL(gen_pool_alloc);
 
 
 /*
- * Allocate the requested number of bytes from the specified pool.
- * Uses a first-fit algorithm.
- *
- * @pool: pool to allocate from
- * @size: number of bytes to allocate from the pool
+ *  Counter-part of the generic allocator.
  */
-unsigned long gen_pool_alloc(struct gen_pool *pool, size_t size)
+void gen_pool_free(struct gen_pool *poolp, unsigned long ptr, int size)
 {
-	struct list_head *_chunk;
-	struct gen_pool_chunk *chunk;
-	unsigned long addr, flags;
-	int order = pool->min_alloc_order;
-	int nbits, bit, start_bit, end_bit;
+	struct gen_pool_link *q;
+	struct gen_pool_link *h = poolp->h;
+	unsigned long a, b, flags;
+	int i, s, max_chunk_size;
 
-	if (size == 0)
-		return 0;
+	max_chunk_size = 1 << poolp->max_chunk_shift;
 
-	nbits = (size + (1UL << order) - 1) >> order;
-
-	read_lock(&pool->lock);
-	list_for_each(_chunk, &pool->chunks) {
-		chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
-
-		end_bit = (chunk->end_addr - chunk->start_addr) >> order;
-		end_bit -= nbits + 1;
-
-		spin_lock_irqsave(&chunk->lock, flags);
-		bit = -1;
-		while (bit + 1 < end_bit) {
-			bit = find_next_zero_bit(chunk->bits, end_bit, bit + 1);
-			if (bit >= end_bit)
-				break;
-
-			start_bit = bit;
-			if (nbits > 1) {
-				bit = find_next_bit(chunk->bits, bit + nbits,
-							bit + 1);
-				if (bit - start_bit < nbits)
-					continue;
-			}
-
-			addr = chunk->start_addr +
-					    ((unsigned long)start_bit << order);
-			while (nbits--)
-				__set_bit(start_bit++, &chunk->bits);
-			spin_unlock_irqrestore(&chunk->lock, flags);
-			read_unlock(&pool->lock);
-			return addr;
+	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;
 		}
-		spin_unlock_irqrestore(&chunk->lock, flags);
-	}
-	read_unlock(&pool->lock);
-	return 0;
-}
-EXPORT_SYMBOL(gen_pool_alloc);
+		b = a ^ s;
+		q = &h[i];
 
+		while (q->next && q->next != (struct gen_pool_link *)b)
+			q = q->next;
 
-/*
- * Free the specified memory back to the specified pool.
- *
- * @pool: pool to free to
- * @addr: starting address of memory to free back to pool
- * @size: size in bytes of memory to free
- */
-void gen_pool_free(struct gen_pool *pool, unsigned long addr, size_t size)
-{
-	struct list_head *_chunk;
-	struct gen_pool_chunk *chunk;
-	unsigned long flags;
-	int order = pool->min_alloc_order;
-	int bit, nbits;
-
-	nbits = (size + (1UL << order) - 1) >> order;
-
-	read_lock(&pool->lock);
-	list_for_each(_chunk, &pool->chunks) {
-		chunk = list_entry(_chunk, struct gen_pool_chunk, next_chunk);
-
-		if (addr >= chunk->start_addr && addr < chunk->end_addr) {
-			BUG_ON(addr + size > chunk->end_addr);
-			spin_lock_irqsave(&chunk->lock, flags);
-			bit = (addr - chunk->start_addr) >> order;
-			while (nbits--)
-				__clear_bit(bit++, &chunk->bits);
-			spin_unlock_irqrestore(&chunk->lock, flags);
+		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++;
 	}
-	BUG_ON(nbits > 0);
-	read_unlock(&pool->lock);
+	spin_unlock_irqrestore(&poolp->lock, flags);
 }
 EXPORT_SYMBOL(gen_pool_free);