[fio.git] / smalloc.c

/*
 * simple memory allocator, backed by mmap() so that it hands out memory
 * that can be shared across processes and threads
 */
#include <sys/mman.h>
#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <unistd.h>
#include <inttypes.h>
#include <sys/types.h>
#include <limits.h>
#include <fcntl.h>

#include "mutex.h"
#include "arch/arch.h"
#include "os/os.h"
#include "smalloc.h"
#include "log.h"

#define SMALLOC_REDZONE		/* define to detect memory corruption */

#define SMALLOC_BPB	32	/* block size, bytes-per-bit in bitmap */
#define SMALLOC_BPI	(sizeof(unsigned int) * 8)
#define SMALLOC_BPL	(SMALLOC_BPB * SMALLOC_BPI)

#define INITIAL_SIZE	8192*1024	/* new pool size */
#define MAX_POOLS	128		/* maximum number of pools to setup */

#define SMALLOC_PRE_RED		0xdeadbeefU
#define SMALLOC_POST_RED	0x5aa55aa5U

unsigned int smalloc_pool_size = INITIAL_SIZE;
static const int int_mask = sizeof(int) - 1;

struct pool {
	struct fio_mutex *lock;			/* protects this pool */
	void *map;				/* map of blocks */
	unsigned int *bitmap;			/* blocks free/busy map */
	size_t free_blocks;		/* free blocks */
	size_t nr_blocks;			/* total blocks */
	size_t next_non_full;
	size_t mmap_size;
};

struct block_hdr {
	size_t size;
#ifdef SMALLOC_REDZONE
	unsigned int prered;
#endif
};

static struct pool mp[MAX_POOLS];
static unsigned int nr_pools;
static unsigned int last_pool;
static struct fio_rwlock *lock;

static inline void pool_lock(struct pool *pool)
{
	fio_mutex_down(pool->lock);
}

static inline void pool_unlock(struct pool *pool)
{
	fio_mutex_up(pool->lock);
}

static inline void global_read_lock(void)
{
	fio_rwlock_read(lock);
}

static inline void global_read_unlock(void)
{
	fio_rwlock_unlock(lock);
}

static inline void global_write_lock(void)
{
	fio_rwlock_write(lock);
}

static inline void global_write_unlock(void)
{
	fio_rwlock_unlock(lock);
}

static inline int ptr_valid(struct pool *pool, void *ptr)
{
	unsigned int pool_size = pool->nr_blocks * SMALLOC_BPL;

	return (ptr >= pool->map) && (ptr < pool->map + pool_size);
}

static inline size_t size_to_blocks(size_t size)
{
	return (size + SMALLOC_BPB - 1) / SMALLOC_BPB;
}

static int blocks_iter(struct pool *pool, unsigned int pool_idx,
		       unsigned int idx, size_t nr_blocks,
		       int (*func)(unsigned int *map, unsigned int mask))
{

	while (nr_blocks) {
		unsigned int this_blocks, mask;
		unsigned int *map;

		if (pool_idx >= pool->nr_blocks)
			return 0;

		map = &pool->bitmap[pool_idx];

		this_blocks = nr_blocks;
		if (this_blocks + idx > SMALLOC_BPI) {
			this_blocks = SMALLOC_BPI - idx;
			idx = SMALLOC_BPI - this_blocks;
		}

		if (this_blocks == SMALLOC_BPI)
			mask = -1U;
		else
			mask = ((1U << this_blocks) - 1) << idx;

		if (!func(map, mask))
			return 0;

		nr_blocks -= this_blocks;
		idx = 0;
		pool_idx++;
	}

	return 1;
}

static int mask_cmp(unsigned int *map, unsigned int mask)
{
	return !(*map & mask);
}

static int mask_clear(unsigned int *map, unsigned int mask)
{
	assert((*map & mask) == mask);
	*map &= ~mask;
	return 1;
}

static int mask_set(unsigned int *map, unsigned int mask)
{
	assert(!(*map & mask));
	*map |= mask;
	return 1;
}

static int blocks_free(struct pool *pool, unsigned int pool_idx,
		       unsigned int idx, size_t nr_blocks)
{
	return blocks_iter(pool, pool_idx, idx, nr_blocks, mask_cmp);
}

static void set_blocks(struct pool *pool, unsigned int pool_idx,
		       unsigned int idx, size_t nr_blocks)
{
	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_set);
}

static void clear_blocks(struct pool *pool, unsigned int pool_idx,
			 unsigned int idx, size_t nr_blocks)
{
	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_clear);
}

static int find_next_zero(int word, int start)
{
	assert(word != -1U);
	word >>= start;
	return ffz(word) + start;
}

static int add_pool(struct pool *pool, unsigned int alloc_size)
{
	int bitmap_blocks;
	int mmap_flags;
	void *ptr;

#ifdef SMALLOC_REDZONE
	alloc_size += sizeof(unsigned int);
#endif
	alloc_size += sizeof(struct block_hdr);
	if (alloc_size < INITIAL_SIZE)
		alloc_size = INITIAL_SIZE;

	/* round up to nearest full number of blocks */
	alloc_size = (alloc_size + SMALLOC_BPL - 1) & ~(SMALLOC_BPL - 1);
	bitmap_blocks = alloc_size / SMALLOC_BPL;
	alloc_size += bitmap_blocks * sizeof(unsigned int);
	pool->mmap_size = alloc_size;

	pool->nr_blocks = bitmap_blocks;
	pool->free_blocks = bitmap_blocks * SMALLOC_BPB;

	mmap_flags = OS_MAP_ANON;
#ifdef CONFIG_ESX
	mmap_flags |= MAP_PRIVATE;
#else
	mmap_flags |= MAP_SHARED;
#endif
	ptr = mmap(NULL, alloc_size, PROT_READ|PROT_WRITE, mmap_flags, -1, 0);

	if (ptr == MAP_FAILED)
		goto out_fail;

	memset(ptr, 0, alloc_size);
	pool->map = ptr;
	pool->bitmap = (void *) ptr + (pool->nr_blocks * SMALLOC_BPL);

	pool->lock = fio_mutex_init(FIO_MUTEX_UNLOCKED);
	if (!pool->lock)
		goto out_fail;

	nr_pools++;
	return 0;
out_fail:
	log_err("smalloc: failed adding pool\n");
	if (pool->map)
		munmap(pool->map, pool->mmap_size);
	return 1;
}

void sinit(void)
{
	int ret;

	lock = fio_rwlock_init();
	ret = add_pool(&mp[0], INITIAL_SIZE);
	assert(!ret);
}

static void cleanup_pool(struct pool *pool)
{
	/*
	 * This will also remove the temporary file we used as a backing
	 * store, it was already unlinked
	 */
	munmap(pool->map, pool->mmap_size);

	if (pool->lock)
		fio_mutex_remove(pool->lock);
}

void scleanup(void)
{
	unsigned int i;

	for (i = 0; i < nr_pools; i++)
		cleanup_pool(&mp[i]);

	if (lock)
		fio_rwlock_remove(lock);
}

#ifdef SMALLOC_REDZONE
static void *postred_ptr(struct block_hdr *hdr)
{
	uintptr_t ptr;

	ptr = (uintptr_t) hdr + hdr->size - sizeof(unsigned int);
	ptr = (ptr + int_mask) & ~int_mask;

	return (void *) ptr;
}

static void fill_redzone(struct block_hdr *hdr)
{
	unsigned int *postred = postred_ptr(hdr);

	hdr->prered = SMALLOC_PRE_RED;
	*postred = SMALLOC_POST_RED;
}

static void sfree_check_redzone(struct block_hdr *hdr)
{
	unsigned int *postred = postred_ptr(hdr);

	if (hdr->prered != SMALLOC_PRE_RED) {
		log_err("smalloc pre redzone destroyed!\n"
			" ptr=%p, prered=%x, expected %x\n",
				hdr, hdr->prered, SMALLOC_PRE_RED);
		assert(0);
	}
	if (*postred != SMALLOC_POST_RED) {
		log_err("smalloc post redzone destroyed!\n"
			"  ptr=%p, postred=%x, expected %x\n",
				hdr, *postred, SMALLOC_POST_RED);
		assert(0);
	}
}
#else
static void fill_redzone(struct block_hdr *hdr)
{
}

static void sfree_check_redzone(struct block_hdr *hdr)
{
}
#endif

static void sfree_pool(struct pool *pool, void *ptr)
{
	struct block_hdr *hdr;
	unsigned int i, idx;
	unsigned long offset;

	if (!ptr)
		return;

	ptr -= sizeof(*hdr);
	hdr = ptr;

	assert(ptr_valid(pool, ptr));

	sfree_check_redzone(hdr);

	offset = ptr - pool->map;
	i = offset / SMALLOC_BPL;
	idx = (offset % SMALLOC_BPL) / SMALLOC_BPB;

	pool_lock(pool);
	clear_blocks(pool, i, idx, size_to_blocks(hdr->size));
	if (i < pool->next_non_full)
		pool->next_non_full = i;
	pool->free_blocks += size_to_blocks(hdr->size);
	pool_unlock(pool);
}

void sfree(void *ptr)
{
	struct pool *pool = NULL;
	unsigned int i;

	if (!ptr)
		return;

	global_read_lock();

	for (i = 0; i < nr_pools; i++) {
		if (ptr_valid(&mp[i], ptr)) {
			pool = &mp[i];
			break;
		}
	}

	global_read_unlock();

	assert(pool);
	sfree_pool(pool, ptr);
}

static void *__smalloc_pool(struct pool *pool, size_t size)
{
	size_t nr_blocks;
	unsigned int i;
	unsigned int offset;
	unsigned int last_idx;
	void *ret = NULL;

	pool_lock(pool);

	nr_blocks = size_to_blocks(size);
	if (nr_blocks > pool->free_blocks)
		goto fail;

	i = pool->next_non_full;
	last_idx = 0;
	offset = -1U;
	while (i < pool->nr_blocks) {
		unsigned int idx;

		if (pool->bitmap[i] == -1U) {
			i++;
			pool->next_non_full = i;
			last_idx = 0;
			continue;
		}

		idx = find_next_zero(pool->bitmap[i], last_idx);
		if (!blocks_free(pool, i, idx, nr_blocks)) {
			idx += nr_blocks;
			if (idx < SMALLOC_BPI)
				last_idx = idx;
			else {
				last_idx = 0;
				while (idx >= SMALLOC_BPI) {
					i++;
					idx -= SMALLOC_BPI;
				}
			}
			continue;
		}
		set_blocks(pool, i, idx, nr_blocks);
		offset = i * SMALLOC_BPL + idx * SMALLOC_BPB;
		break;
	}

	if (i < pool->nr_blocks) {
		pool->free_blocks -= nr_blocks;
		ret = pool->map + offset;
	}
fail:
	pool_unlock(pool);
	return ret;
}

static void *smalloc_pool(struct pool *pool, size_t size)
{
	size_t alloc_size = size + sizeof(struct block_hdr);
	void *ptr;

	/*
	 * Round to int alignment, so that the postred pointer will
	 * be naturally aligned as well.
	 */
#ifdef SMALLOC_REDZONE
	alloc_size += sizeof(unsigned int);
	alloc_size = (alloc_size + int_mask) & ~int_mask;
#endif

	ptr = __smalloc_pool(pool, alloc_size);
	if (ptr) {
		struct block_hdr *hdr = ptr;

		hdr->size = alloc_size;
		fill_redzone(hdr);

		ptr += sizeof(*hdr);
		memset(ptr, 0, size);
	}

	return ptr;
}

void *smalloc(size_t size)
{
	unsigned int i;

	if (size != (unsigned int) size)
		return NULL;

	global_write_lock();
	i = last_pool;

	do {
		for (; i < nr_pools; i++) {
			void *ptr = smalloc_pool(&mp[i], size);

			if (ptr) {
				last_pool = i;
				global_write_unlock();
				return ptr;
			}
		}
		if (last_pool) {
			last_pool = 0;
			continue;
		}

		if (nr_pools + 1 > MAX_POOLS)
			break;
		else {
			i = nr_pools;
			if (add_pool(&mp[nr_pools], size))
				goto out;
		}
	} while (1);

out:
	global_write_unlock();
	return NULL;
}

char *smalloc_strdup(const char *str)
{
	char *ptr;

	ptr = smalloc(strlen(str) + 1);
	strcpy(ptr, str);
	return ptr;
}
Commit	Line	Data
	1	/*
	2	* simple memory allocator, backed by mmap() so that it hands out memory
	3	* that can be shared across processes and threads
	4	*/
	5	#include <sys/mman.h>
	6	#include <stdio.h>
	7	#include <stdlib.h>
	8	#include <assert.h>
	9	#include <string.h>
	10	#include <unistd.h>
	11	#include <inttypes.h>
	12	#include <sys/types.h>
	13	#include <limits.h>
	14	#include <fcntl.h>
	15
	16	#include "mutex.h"
	17	#include "arch/arch.h"
	18	#include "os/os.h"
	19	#include "smalloc.h"
	20	#include "log.h"
	21
	22	#define SMALLOC_REDZONE /* define to detect memory corruption */
	23
	24	#define SMALLOC_BPB 32 /* block size, bytes-per-bit in bitmap */
	25	#define SMALLOC_BPI (sizeof(unsigned int) * 8)
	26	#define SMALLOC_BPL (SMALLOC_BPB * SMALLOC_BPI)
	27
	28	#define INITIAL_SIZE 81921024 / new pool size */
	29	#define MAX_POOLS 128 /* maximum number of pools to setup */
	30
	31	#define SMALLOC_PRE_RED 0xdeadbeefU
	32	#define SMALLOC_POST_RED 0x5aa55aa5U
	33
	34	unsigned int smalloc_pool_size = INITIAL_SIZE;
	35	static const int int_mask = sizeof(int) - 1;
	36
	37	struct pool {
	38	struct fio_mutex lock; / protects this pool */
	39	void map; / map of blocks */
	40	unsigned int bitmap; / blocks free/busy map */
	41	size_t free_blocks; /* free blocks */
	42	size_t nr_blocks; /* total blocks */
	43	size_t next_non_full;
	44	size_t mmap_size;
	45	};
	46
	47	struct block_hdr {
	48	size_t size;
	49	#ifdef SMALLOC_REDZONE
	50	unsigned int prered;
	51	#endif
	52	};
	53
	54	static struct pool mp[MAX_POOLS];
	55	static unsigned int nr_pools;
	56	static unsigned int last_pool;
	57	static struct fio_rwlock *lock;
	58
	59	static inline void pool_lock(struct pool *pool)
	60	{
	61	fio_mutex_down(pool->lock);
	62	}
	63
	64	static inline void pool_unlock(struct pool *pool)
	65	{
	66	fio_mutex_up(pool->lock);
	67	}
	68
	69	static inline void global_read_lock(void)
	70	{
	71	fio_rwlock_read(lock);
	72	}
	73
	74	static inline void global_read_unlock(void)
	75	{
	76	fio_rwlock_unlock(lock);
	77	}
	78
	79	static inline void global_write_lock(void)
	80	{
	81	fio_rwlock_write(lock);
	82	}
	83
	84	static inline void global_write_unlock(void)
	85	{
	86	fio_rwlock_unlock(lock);
	87	}
	88
	89	static inline int ptr_valid(struct pool pool, void ptr)
	90	{
	91	unsigned int pool_size = pool->nr_blocks * SMALLOC_BPL;
	92
	93	return (ptr >= pool->map) && (ptr < pool->map + pool_size);
	94	}
	95
	96	static inline size_t size_to_blocks(size_t size)
	97	{
	98	return (size + SMALLOC_BPB - 1) / SMALLOC_BPB;
	99	}
	100
	101	static int blocks_iter(struct pool *pool, unsigned int pool_idx,
	102	unsigned int idx, size_t nr_blocks,
	103	int (func)(unsigned int map, unsigned int mask))
	104	{
	105
	106	while (nr_blocks) {
	107	unsigned int this_blocks, mask;
	108	unsigned int *map;
	109
	110	if (pool_idx >= pool->nr_blocks)
	111	return 0;
	112
	113	map = &pool->bitmap[pool_idx];
	114
	115	this_blocks = nr_blocks;
	116	if (this_blocks + idx > SMALLOC_BPI) {
	117	this_blocks = SMALLOC_BPI - idx;
	118	idx = SMALLOC_BPI - this_blocks;
	119	}
	120
	121	if (this_blocks == SMALLOC_BPI)
	122	mask = -1U;
	123	else
	124	mask = ((1U << this_blocks) - 1) << idx;
	125
	126	if (!func(map, mask))
	127	return 0;
	128
	129	nr_blocks -= this_blocks;
	130	idx = 0;
	131	pool_idx++;
	132	}
	133
	134	return 1;
	135	}
	136
	137	static int mask_cmp(unsigned int *map, unsigned int mask)
	138	{
	139	return !(*map & mask);
	140	}
	141
	142	static int mask_clear(unsigned int *map, unsigned int mask)
	143	{
	144	assert((*map & mask) == mask);
	145	*map &= ~mask;
	146	return 1;
	147	}
	148
	149	static int mask_set(unsigned int *map, unsigned int mask)
	150	{
	151	assert(!(*map & mask));
	152	*map \|= mask;
	153	return 1;
	154	}
	155
	156	static int blocks_free(struct pool *pool, unsigned int pool_idx,
	157	unsigned int idx, size_t nr_blocks)
	158	{
	159	return blocks_iter(pool, pool_idx, idx, nr_blocks, mask_cmp);
	160	}
	161
	162	static void set_blocks(struct pool *pool, unsigned int pool_idx,
	163	unsigned int idx, size_t nr_blocks)
	164	{
	165	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_set);
	166	}
	167
	168	static void clear_blocks(struct pool *pool, unsigned int pool_idx,
	169	unsigned int idx, size_t nr_blocks)
	170	{
	171	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_clear);
	172	}
	173
	174	static int find_next_zero(int word, int start)
	175	{
	176	assert(word != -1U);
	177	word >>= start;
	178	return ffz(word) + start;
	179	}
	180
	181	static int add_pool(struct pool *pool, unsigned int alloc_size)
	182	{
	183	int bitmap_blocks;
	184	int mmap_flags;
	185	void *ptr;
	186
	187	#ifdef SMALLOC_REDZONE
	188	alloc_size += sizeof(unsigned int);
	189	#endif
	190	alloc_size += sizeof(struct block_hdr);
	191	if (alloc_size < INITIAL_SIZE)
	192	alloc_size = INITIAL_SIZE;
	193
	194	/* round up to nearest full number of blocks */
	195	alloc_size = (alloc_size + SMALLOC_BPL - 1) & ~(SMALLOC_BPL - 1);
	196	bitmap_blocks = alloc_size / SMALLOC_BPL;
	197	alloc_size += bitmap_blocks * sizeof(unsigned int);
	198	pool->mmap_size = alloc_size;
	199
	200	pool->nr_blocks = bitmap_blocks;
	201	pool->free_blocks = bitmap_blocks * SMALLOC_BPB;
	202
	203	mmap_flags = OS_MAP_ANON;
	204	#ifdef CONFIG_ESX
	205	mmap_flags \|= MAP_PRIVATE;
	206	#else
	207	mmap_flags \|= MAP_SHARED;
	208	#endif
	209	ptr = mmap(NULL, alloc_size, PROT_READ\|PROT_WRITE, mmap_flags, -1, 0);
	210
	211	if (ptr == MAP_FAILED)
	212	goto out_fail;
	213
	214	memset(ptr, 0, alloc_size);
	215	pool->map = ptr;
	216	pool->bitmap = (void ) ptr + (pool->nr_blocks SMALLOC_BPL);
	217
	218	pool->lock = fio_mutex_init(FIO_MUTEX_UNLOCKED);
	219	if (!pool->lock)
	220	goto out_fail;
	221
	222	nr_pools++;
	223	return 0;
	224	out_fail:
	225	log_err("smalloc: failed adding pool\n");
	226	if (pool->map)
	227	munmap(pool->map, pool->mmap_size);
	228	return 1;
	229	}
	230
	231	void sinit(void)
	232	{
	233	int ret;
	234
	235	lock = fio_rwlock_init();
	236	ret = add_pool(&mp[0], INITIAL_SIZE);
	237	assert(!ret);
	238	}
	239
	240	static void cleanup_pool(struct pool *pool)
	241	{
	242	/*
	243	* This will also remove the temporary file we used as a backing
	244	* store, it was already unlinked
	245	*/
	246	munmap(pool->map, pool->mmap_size);
	247
	248	if (pool->lock)
	249	fio_mutex_remove(pool->lock);
	250	}
	251
	252	void scleanup(void)
	253	{
	254	unsigned int i;
	255
	256	for (i = 0; i < nr_pools; i++)
	257	cleanup_pool(&mp[i]);
	258
	259	if (lock)
	260	fio_rwlock_remove(lock);
	261	}
	262
	263	#ifdef SMALLOC_REDZONE
	264	static void postred_ptr(struct block_hdr hdr)
	265	{
	266	uintptr_t ptr;
	267
	268	ptr = (uintptr_t) hdr + hdr->size - sizeof(unsigned int);
	269	ptr = (ptr + int_mask) & ~int_mask;
	270
	271	return (void *) ptr;
	272	}
	273
	274	static void fill_redzone(struct block_hdr *hdr)
	275	{
	276	unsigned int *postred = postred_ptr(hdr);
	277
	278	hdr->prered = SMALLOC_PRE_RED;
	279	*postred = SMALLOC_POST_RED;
	280	}
	281
	282	static void sfree_check_redzone(struct block_hdr *hdr)
	283	{
	284	unsigned int *postred = postred_ptr(hdr);
	285
	286	if (hdr->prered != SMALLOC_PRE_RED) {
	287	log_err("smalloc pre redzone destroyed!\n"
	288	" ptr=%p, prered=%x, expected %x\n",
	289	hdr, hdr->prered, SMALLOC_PRE_RED);
	290	assert(0);
	291	}
	292	if (*postred != SMALLOC_POST_RED) {
	293	log_err("smalloc post redzone destroyed!\n"
	294	" ptr=%p, postred=%x, expected %x\n",
	295	hdr, *postred, SMALLOC_POST_RED);
	296	assert(0);
	297	}
	298	}
	299	#else
	300	static void fill_redzone(struct block_hdr *hdr)
	301	{
	302	}
	303
	304	static void sfree_check_redzone(struct block_hdr *hdr)
	305	{
	306	}
	307	#endif
	308
	309	static void sfree_pool(struct pool pool, void ptr)
	310	{
	311	struct block_hdr *hdr;
	312	unsigned int i, idx;
	313	unsigned long offset;
	314
	315	if (!ptr)
	316	return;
	317
	318	ptr -= sizeof(*hdr);
	319	hdr = ptr;
	320
	321	assert(ptr_valid(pool, ptr));
	322
	323	sfree_check_redzone(hdr);
	324
	325	offset = ptr - pool->map;
	326	i = offset / SMALLOC_BPL;
	327	idx = (offset % SMALLOC_BPL) / SMALLOC_BPB;
	328
	329	pool_lock(pool);
	330	clear_blocks(pool, i, idx, size_to_blocks(hdr->size));
	331	if (i < pool->next_non_full)
	332	pool->next_non_full = i;
	333	pool->free_blocks += size_to_blocks(hdr->size);
	334	pool_unlock(pool);
	335	}
	336
	337	void sfree(void *ptr)
	338	{
	339	struct pool *pool = NULL;
	340	unsigned int i;
	341
	342	if (!ptr)
	343	return;
	344
	345	global_read_lock();
	346
	347	for (i = 0; i < nr_pools; i++) {
	348	if (ptr_valid(&mp[i], ptr)) {
	349	pool = &mp[i];
	350	break;
	351	}
	352	}
	353
	354	global_read_unlock();
	355
	356	assert(pool);
	357	sfree_pool(pool, ptr);
	358	}
	359
	360	static void __smalloc_pool(struct pool pool, size_t size)
	361	{
	362	size_t nr_blocks;
	363	unsigned int i;
	364	unsigned int offset;
	365	unsigned int last_idx;
	366	void *ret = NULL;
	367
	368	pool_lock(pool);
	369
	370	nr_blocks = size_to_blocks(size);
	371	if (nr_blocks > pool->free_blocks)
	372	goto fail;
	373
	374	i = pool->next_non_full;
	375	last_idx = 0;
	376	offset = -1U;
	377	while (i < pool->nr_blocks) {
	378	unsigned int idx;
	379
	380	if (pool->bitmap[i] == -1U) {
	381	i++;
	382	pool->next_non_full = i;
	383	last_idx = 0;
	384	continue;
	385	}
	386
	387	idx = find_next_zero(pool->bitmap[i], last_idx);
	388	if (!blocks_free(pool, i, idx, nr_blocks)) {
	389	idx += nr_blocks;
	390	if (idx < SMALLOC_BPI)
	391	last_idx = idx;
	392	else {
	393	last_idx = 0;
	394	while (idx >= SMALLOC_BPI) {
	395	i++;
	396	idx -= SMALLOC_BPI;
	397	}
	398	}
	399	continue;
	400	}
	401	set_blocks(pool, i, idx, nr_blocks);
	402	offset = i * SMALLOC_BPL + idx * SMALLOC_BPB;
	403	break;
	404	}
	405
	406	if (i < pool->nr_blocks) {
	407	pool->free_blocks -= nr_blocks;
	408	ret = pool->map + offset;
	409	}
	410	fail:
	411	pool_unlock(pool);
	412	return ret;
	413	}
	414
	415	static void smalloc_pool(struct pool pool, size_t size)
	416	{
	417	size_t alloc_size = size + sizeof(struct block_hdr);
	418	void *ptr;
	419
	420	/*
	421	* Round to int alignment, so that the postred pointer will
	422	* be naturally aligned as well.
	423	*/
	424	#ifdef SMALLOC_REDZONE
	425	alloc_size += sizeof(unsigned int);
	426	alloc_size = (alloc_size + int_mask) & ~int_mask;
	427	#endif
	428
	429	ptr = __smalloc_pool(pool, alloc_size);
	430	if (ptr) {
	431	struct block_hdr *hdr = ptr;
	432
	433	hdr->size = alloc_size;
	434	fill_redzone(hdr);
	435
	436	ptr += sizeof(*hdr);
	437	memset(ptr, 0, size);
	438	}
	439
	440	return ptr;
	441	}
	442
	443	void *smalloc(size_t size)
	444	{
	445	unsigned int i;
	446
	447	if (size != (unsigned int) size)
	448	return NULL;
	449
	450	global_write_lock();
	451	i = last_pool;
	452
	453	do {
	454	for (; i < nr_pools; i++) {
	455	void *ptr = smalloc_pool(&mp[i], size);
	456
	457	if (ptr) {
	458	last_pool = i;
	459	global_write_unlock();
	460	return ptr;
	461	}
	462	}
	463	if (last_pool) {
	464	last_pool = 0;
	465	continue;
	466	}
	467
	468	if (nr_pools + 1 > MAX_POOLS)
	469	break;
	470	else {
	471	i = nr_pools;
	472	if (add_pool(&mp[nr_pools], size))
	473	goto out;
	474	}
	475	} while (1);
	476
	477	out:
	478	global_write_unlock();
	479	return NULL;
	480	}
	481
	482	char smalloc_strdup(const char str)
	483	{
	484	char *ptr;
	485
	486	ptr = smalloc(strlen(str) + 1);
	487	strcpy(ptr, str);
	488	return ptr;
	489	}