[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 <sys/types.h>
#include <limits.h>

#include "mutex.h"
#include "arch/arch.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;
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 */
	unsigned int free_blocks;		/* free blocks */
	unsigned int nr_blocks;			/* total blocks */
	unsigned int next_non_full;
	int fd;					/* memory backing fd */
	unsigned int mmap_size;
};

struct block_hdr {
	unsigned int 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_mutex *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_mutex_down_read(lock);
}

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

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

static inline void global_write_unlock(void)
{
	fio_mutex_up_write(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 unsigned int size_to_blocks(unsigned int size)
{
	return (size + SMALLOC_BPB - 1) / SMALLOC_BPB;
}

static int blocks_iter(struct pool *pool, unsigned int pool_idx,
		       unsigned int idx, unsigned int 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, unsigned int 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, unsigned int 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, unsigned int 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 + 1);
	return ffz(word) + start + 1;
}

static int add_pool(struct pool *pool, unsigned int alloc_size)
{
	int fd, bitmap_blocks;
	char file[] = "/tmp/.fio_smalloc.XXXXXX";
	void *ptr;

	fd = mkstemp(file);
	if (fd < 0)
		goto out_close;

#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;

	if (ftruncate(fd, alloc_size) < 0)
		goto out_unlink;

	ptr = mmap(NULL, alloc_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
	if (ptr == MAP_FAILED)
		goto out_unlink;

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

	pool->lock = fio_mutex_init(1);
	if (!pool->lock)
		goto out_unlink;

	/*
	 * Unlink pool file now. It wont get deleted until the fd is closed,
	 * which happens both for cleanup or unexpected quit. This way we
	 * don't leave temp files around in case of a crash.
	 */
	unlink(file);
	pool->fd = fd;

	nr_pools++;
	return 0;
out_unlink:
	fprintf(stderr, "smalloc: failed adding pool\n");
	if (pool->map)
		munmap(pool->map, pool->mmap_size);
	unlink(file);
out_close:
	close(fd);
	return 1;
}

void sinit(void)
{
	int ret;

	lock = fio_mutex_rw_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
	 */
	close(pool->fd);
	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_mutex_remove(lock);
}

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

	ptr = (unsigned long) 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) {
		fprintf(stderr, "smalloc pre redzone destroyed!\n");
		fprintf(stderr, "  ptr=%p, prered=%x, expected %x\n",
				hdr, hdr->prered, SMALLOC_PRE_RED);
		assert(0);
	}
	if (*postred != SMALLOC_POST_RED) {
		fprintf(stderr, "smalloc post redzone destroyed!\n");
		fprintf(stderr, "  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, unsigned int size)
{
	unsigned int 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, unsigned int size)
{
	unsigned int 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(unsigned int size)
{
	unsigned int i;

	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 <sys/types.h>
	12	#include <limits.h>
	13
	14	#include "mutex.h"
	15	#include "arch/arch.h"
	16
	17	#define SMALLOC_REDZONE /* define to detect memory corruption */
	18
	19	#define SMALLOC_BPB 32 /* block size, bytes-per-bit in bitmap */
	20	#define SMALLOC_BPI (sizeof(unsigned int) * 8)
	21	#define SMALLOC_BPL (SMALLOC_BPB * SMALLOC_BPI)
	22
	23	#define INITIAL_SIZE 81921024 / new pool size */
	24	#define MAX_POOLS 128 /* maximum number of pools to setup */
	25
	26	#define SMALLOC_PRE_RED 0xdeadbeefU
	27	#define SMALLOC_POST_RED 0x5aa55aa5U
	28
	29	unsigned int smalloc_pool_size = INITIAL_SIZE;
	30	const int int_mask = sizeof(int) - 1;
	31
	32	struct pool {
	33	struct fio_mutex lock; / protects this pool */
	34	void map; / map of blocks */
	35	unsigned int bitmap; / blocks free/busy map */
	36	unsigned int free_blocks; /* free blocks */
	37	unsigned int nr_blocks; /* total blocks */
	38	unsigned int next_non_full;
	39	int fd; /* memory backing fd */
	40	unsigned int mmap_size;
	41	};
	42
	43	struct block_hdr {
	44	unsigned int size;
	45	#ifdef SMALLOC_REDZONE
	46	unsigned int prered;
	47	#endif
	48	};
	49
	50	static struct pool mp[MAX_POOLS];
	51	static unsigned int nr_pools;
	52	static unsigned int last_pool;
	53	static struct fio_mutex *lock;
	54
	55	static inline void pool_lock(struct pool *pool)
	56	{
	57	fio_mutex_down(pool->lock);
	58	}
	59
	60	static inline void pool_unlock(struct pool *pool)
	61	{
	62	fio_mutex_up(pool->lock);
	63	}
	64
	65	static inline void global_read_lock(void)
	66	{
	67	fio_mutex_down_read(lock);
	68	}
	69
	70	static inline void global_read_unlock(void)
	71	{
	72	fio_mutex_up_read(lock);
	73	}
	74
	75	static inline void global_write_lock(void)
	76	{
	77	fio_mutex_down_write(lock);
	78	}
	79
	80	static inline void global_write_unlock(void)
	81	{
	82	fio_mutex_up_write(lock);
	83	}
	84
	85	static inline int ptr_valid(struct pool pool, void ptr)
	86	{
	87	unsigned int pool_size = pool->nr_blocks * SMALLOC_BPL;
	88
	89	return (ptr >= pool->map) && (ptr < pool->map + pool_size);
	90	}
	91
	92	static inline unsigned int size_to_blocks(unsigned int size)
	93	{
	94	return (size + SMALLOC_BPB - 1) / SMALLOC_BPB;
	95	}
	96
	97	static int blocks_iter(struct pool *pool, unsigned int pool_idx,
	98	unsigned int idx, unsigned int nr_blocks,
	99	int (func)(unsigned int map, unsigned int mask))
	100	{
	101
	102	while (nr_blocks) {
	103	unsigned int this_blocks, mask;
	104	unsigned int *map;
	105
	106	if (pool_idx >= pool->nr_blocks)
	107	return 0;
	108
	109	map = &pool->bitmap[pool_idx];
	110
	111	this_blocks = nr_blocks;
	112	if (this_blocks + idx > SMALLOC_BPI) {
	113	this_blocks = SMALLOC_BPI - idx;
	114	idx = SMALLOC_BPI - this_blocks;
	115	}
	116
	117	if (this_blocks == SMALLOC_BPI)
	118	mask = -1U;
	119	else
	120	mask = ((1U << this_blocks) - 1) << idx;
	121
	122	if (!func(map, mask))
	123	return 0;
	124
	125	nr_blocks -= this_blocks;
	126	idx = 0;
	127	pool_idx++;
	128	}
	129
	130	return 1;
	131	}
	132
	133	static int mask_cmp(unsigned int *map, unsigned int mask)
	134	{
	135	return !(*map & mask);
	136	}
	137
	138	static int mask_clear(unsigned int *map, unsigned int mask)
	139	{
	140	assert((*map & mask) == mask);
	141	*map &= ~mask;
	142	return 1;
	143	}
	144
	145	static int mask_set(unsigned int *map, unsigned int mask)
	146	{
	147	assert(!(*map & mask));
	148	*map \|= mask;
	149	return 1;
	150	}
	151
	152	static int blocks_free(struct pool *pool, unsigned int pool_idx,
	153	unsigned int idx, unsigned int nr_blocks)
	154	{
	155	return blocks_iter(pool, pool_idx, idx, nr_blocks, mask_cmp);
	156	}
	157
	158	static void set_blocks(struct pool *pool, unsigned int pool_idx,
	159	unsigned int idx, unsigned int nr_blocks)
	160	{
	161	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_set);
	162	}
	163
	164	static void clear_blocks(struct pool *pool, unsigned int pool_idx,
	165	unsigned int idx, unsigned int nr_blocks)
	166	{
	167	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_clear);
	168	}
	169
	170	static int find_next_zero(int word, int start)
	171	{
	172	assert(word != -1U);
	173	word >>= (start + 1);
	174	return ffz(word) + start + 1;
	175	}
	176
	177	static int add_pool(struct pool *pool, unsigned int alloc_size)
	178	{
	179	int fd, bitmap_blocks;
	180	char file[] = "/tmp/.fio_smalloc.XXXXXX";
	181	void *ptr;
	182
	183	fd = mkstemp(file);
	184	if (fd < 0)
	185	goto out_close;
	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	if (ftruncate(fd, alloc_size) < 0)
	204	goto out_unlink;
	205
	206	ptr = mmap(NULL, alloc_size, PROT_READ\|PROT_WRITE, MAP_SHARED, fd, 0);
	207	if (ptr == MAP_FAILED)
	208	goto out_unlink;
	209
	210	memset(ptr, 0, alloc_size);
	211	pool->map = ptr;
	212	pool->bitmap = (void ) ptr + (pool->nr_blocks SMALLOC_BPL);
	213
	214	pool->lock = fio_mutex_init(1);
	215	if (!pool->lock)
	216	goto out_unlink;
	217
	218	/*
	219	* Unlink pool file now. It wont get deleted until the fd is closed,
	220	* which happens both for cleanup or unexpected quit. This way we
	221	* don't leave temp files around in case of a crash.
	222	*/
	223	unlink(file);
	224	pool->fd = fd;
	225
	226	nr_pools++;
	227	return 0;
	228	out_unlink:
	229	fprintf(stderr, "smalloc: failed adding pool\n");
	230	if (pool->map)
	231	munmap(pool->map, pool->mmap_size);
	232	unlink(file);
	233	out_close:
	234	close(fd);
	235	return 1;
	236	}
	237
	238	void sinit(void)
	239	{
	240	int ret;
	241
	242	lock = fio_mutex_rw_init();
	243	ret = add_pool(&mp[0], INITIAL_SIZE);
	244	assert(!ret);
	245	}
	246
	247	static void cleanup_pool(struct pool *pool)
	248	{
	249	/*
	250	* This will also remove the temporary file we used as a backing
	251	* store, it was already unlinked
	252	*/
	253	close(pool->fd);
	254	munmap(pool->map, pool->mmap_size);
	255
	256	if (pool->lock)
	257	fio_mutex_remove(pool->lock);
	258	}
	259
	260	void scleanup(void)
	261	{
	262	unsigned int i;
	263
	264	for (i = 0; i < nr_pools; i++)
	265	cleanup_pool(&mp[i]);
	266
	267	if (lock)
	268	fio_mutex_remove(lock);
	269	}
	270
	271	#ifdef SMALLOC_REDZONE
	272	static void postred_ptr(struct block_hdr hdr)
	273	{
	274	unsigned long ptr;
	275
	276	ptr = (unsigned long) hdr + hdr->size - sizeof(unsigned int);
	277	ptr = (ptr + int_mask) & ~int_mask;
	278
	279	return (void *) ptr;
	280	}
	281
	282	static void fill_redzone(struct block_hdr *hdr)
	283	{
	284	unsigned int *postred = postred_ptr(hdr);
	285
	286	hdr->prered = SMALLOC_PRE_RED;
	287	*postred = SMALLOC_POST_RED;
	288	}
	289
	290	static void sfree_check_redzone(struct block_hdr *hdr)
	291	{
	292	unsigned int *postred = postred_ptr(hdr);
	293
	294	if (hdr->prered != SMALLOC_PRE_RED) {
	295	fprintf(stderr, "smalloc pre redzone destroyed!\n");
	296	fprintf(stderr, " ptr=%p, prered=%x, expected %x\n",
	297	hdr, hdr->prered, SMALLOC_PRE_RED);
	298	assert(0);
	299	}
	300	if (*postred != SMALLOC_POST_RED) {
	301	fprintf(stderr, "smalloc post redzone destroyed!\n");
	302	fprintf(stderr, " ptr=%p, postred=%x, expected %x\n",
	303	hdr, *postred, SMALLOC_POST_RED);
	304	assert(0);
	305	}
	306	}
	307	#else
	308	static void fill_redzone(struct block_hdr *hdr)
	309	{
	310	}
	311
	312	static void sfree_check_redzone(struct block_hdr *hdr)
	313	{
	314	}
	315	#endif
	316
	317	static void sfree_pool(struct pool pool, void ptr)
	318	{
	319	struct block_hdr *hdr;
	320	unsigned int i, idx;
	321	unsigned long offset;
	322
	323	if (!ptr)
	324	return;
	325
	326	ptr -= sizeof(*hdr);
	327	hdr = ptr;
	328
	329	assert(ptr_valid(pool, ptr));
	330
	331	sfree_check_redzone(hdr);
	332
	333	offset = ptr - pool->map;
	334	i = offset / SMALLOC_BPL;
	335	idx = (offset % SMALLOC_BPL) / SMALLOC_BPB;
	336
	337	pool_lock(pool);
	338	clear_blocks(pool, i, idx, size_to_blocks(hdr->size));
	339	if (i < pool->next_non_full)
	340	pool->next_non_full = i;
	341	pool->free_blocks += size_to_blocks(hdr->size);
	342	pool_unlock(pool);
	343	}
	344
	345	void sfree(void *ptr)
	346	{
	347	struct pool *pool = NULL;
	348	unsigned int i;
	349
	350	if (!ptr)
	351	return;
	352
	353	global_read_lock();
	354
	355	for (i = 0; i < nr_pools; i++) {
	356	if (ptr_valid(&mp[i], ptr)) {
	357	pool = &mp[i];
	358	break;
	359	}
	360	}
	361
	362	global_read_unlock();
	363
	364	assert(pool);
	365	sfree_pool(pool, ptr);
	366	}
	367
	368	static void __smalloc_pool(struct pool pool, unsigned int size)
	369	{
	370	unsigned int nr_blocks;
	371	unsigned int i;
	372	unsigned int offset;
	373	unsigned int last_idx;
	374	void *ret = NULL;
	375
	376	pool_lock(pool);
	377
	378	nr_blocks = size_to_blocks(size);
	379	if (nr_blocks > pool->free_blocks)
	380	goto fail;
	381
	382	i = pool->next_non_full;
	383	last_idx = 0;
	384	offset = -1U;
	385	while (i < pool->nr_blocks) {
	386	unsigned int idx;
	387
	388	if (pool->bitmap[i] == -1U) {
	389	i++;
	390	pool->next_non_full = i;
	391	last_idx = 0;
	392	continue;
	393	}
	394
	395	idx = find_next_zero(pool->bitmap[i], last_idx);
	396	if (!blocks_free(pool, i, idx, nr_blocks)) {
	397	idx += nr_blocks;
	398	if (idx < SMALLOC_BPI)
	399	last_idx = idx;
	400	else {
	401	last_idx = 0;
	402	while (idx >= SMALLOC_BPI) {
	403	i++;
	404	idx -= SMALLOC_BPI;
	405	}
	406	}
	407	continue;
	408	}
	409	set_blocks(pool, i, idx, nr_blocks);
	410	offset = i * SMALLOC_BPL + idx * SMALLOC_BPB;
	411	break;
	412	}
	413
	414	if (i < pool->nr_blocks) {
	415	pool->free_blocks -= nr_blocks;
	416	ret = pool->map + offset;
	417	}
	418	fail:
	419	pool_unlock(pool);
	420	return ret;
	421	}
	422
	423	static void smalloc_pool(struct pool pool, unsigned int size)
	424	{
	425	unsigned int alloc_size = size + sizeof(struct block_hdr);
	426	void *ptr;
	427
	428	/*
	429	* Round to int alignment, so that the postred pointer will
	430	* be naturally aligned as well.
	431	*/
	432	#ifdef SMALLOC_REDZONE
	433	alloc_size += sizeof(unsigned int);
	434	alloc_size = (alloc_size + int_mask) & ~int_mask;
	435	#endif
	436
	437	ptr = __smalloc_pool(pool, alloc_size);
	438	if (ptr) {
	439	struct block_hdr *hdr = ptr;
	440
	441	hdr->size = alloc_size;
	442	fill_redzone(hdr);
	443
	444	ptr += sizeof(*hdr);
	445	memset(ptr, 0, size);
	446	}
	447
	448	return ptr;
	449	}
	450
	451	void *smalloc(unsigned int size)
	452	{
	453	unsigned int i;
	454
	455	global_write_lock();
	456	i = last_pool;
	457
	458	do {
	459	for (; i < nr_pools; i++) {
	460	void *ptr = smalloc_pool(&mp[i], size);
	461
	462	if (ptr) {
	463	last_pool = i;
	464	global_write_unlock();
	465	return ptr;
	466	}
	467	}
	468	if (last_pool) {
	469	last_pool = 0;
	470	continue;
	471	}
	472
	473	if (nr_pools + 1 > MAX_POOLS)
	474	break;
	475	else {
	476	i = nr_pools;
	477	if (add_pool(&mp[nr_pools], size))
	478	goto out;
	479	}
	480	} while (1);
	481
	482	out:
	483	global_write_unlock();
	484	return NULL;
	485	}
	486
	487	char smalloc_strdup(const char str)
	488	{
	489	char *ptr;
	490
	491	ptr = smalloc(strlen(str) + 1);
	492	strcpy(ptr, str);
	493	return ptr;
	494	}