[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	16*1024*1024	/* new pool size */
#define MAX_POOLS	8		/* 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 i, ret;

	lock = fio_rwlock_init();

	for (i = 0; i < MAX_POOLS; i++) {
		ret = add_pool(&mp[i], INITIAL_SIZE);
		if (ret)
			break;
	}

	/*
	 * If we added at least one pool, we should be OK for most
	 * cases.
	 */
	assert(i);
}

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();

	if (pool) {
		sfree_pool(pool, ptr);
		return;
	}

	log_err("smalloc: ptr %p not from smalloc pool\n", 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, end_pool;

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

	global_write_lock();
	i = last_pool;
	end_pool = nr_pools;

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

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

		break;
	} while (1);

	global_write_unlock();
	return NULL;
}

void *scalloc(size_t nmemb, size_t size)
{
	void *ret;

	ret = smalloc(nmemb * size);
	if (ret)
		memset(ret, 0, nmemb * size);

	return ret;
}

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

	ptr = smalloc(strlen(str) + 1);
	if (ptr)
		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 1610241024 /* new pool size */
	29	#define MAX_POOLS 8 /* 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 i, ret;
	234
	235	lock = fio_rwlock_init();
	236
	237	for (i = 0; i < MAX_POOLS; i++) {
	238	ret = add_pool(&mp[i], INITIAL_SIZE);
	239	if (ret)
	240	break;
	241	}
	242
	243	/*
	244	* If we added at least one pool, we should be OK for most
	245	* cases.
	246	*/
	247	assert(i);
	248	}
	249
	250	static void cleanup_pool(struct pool *pool)
	251	{
	252	/*
	253	* This will also remove the temporary file we used as a backing
	254	* store, it was already unlinked
	255	*/
	256	munmap(pool->map, pool->mmap_size);
	257
	258	if (pool->lock)
	259	fio_mutex_remove(pool->lock);
	260	}
	261
	262	void scleanup(void)
	263	{
	264	unsigned int i;
	265
	266	for (i = 0; i < nr_pools; i++)
	267	cleanup_pool(&mp[i]);
	268
	269	if (lock)
	270	fio_rwlock_remove(lock);
	271	}
	272
	273	#ifdef SMALLOC_REDZONE
	274	static void postred_ptr(struct block_hdr hdr)
	275	{
	276	uintptr_t ptr;
	277
	278	ptr = (uintptr_t) hdr + hdr->size - sizeof(unsigned int);
	279	ptr = (ptr + int_mask) & ~int_mask;
	280
	281	return (void *) ptr;
	282	}
	283
	284	static void fill_redzone(struct block_hdr *hdr)
	285	{
	286	unsigned int *postred = postred_ptr(hdr);
	287
	288	hdr->prered = SMALLOC_PRE_RED;
	289	*postred = SMALLOC_POST_RED;
	290	}
	291
	292	static void sfree_check_redzone(struct block_hdr *hdr)
	293	{
	294	unsigned int *postred = postred_ptr(hdr);
	295
	296	if (hdr->prered != SMALLOC_PRE_RED) {
	297	log_err("smalloc pre redzone destroyed!\n"
	298	" ptr=%p, prered=%x, expected %x\n",
	299	hdr, hdr->prered, SMALLOC_PRE_RED);
	300	assert(0);
	301	}
	302	if (*postred != SMALLOC_POST_RED) {
	303	log_err("smalloc post redzone destroyed!\n"
	304	" ptr=%p, postred=%x, expected %x\n",
	305	hdr, *postred, SMALLOC_POST_RED);
	306	assert(0);
	307	}
	308	}
	309	#else
	310	static void fill_redzone(struct block_hdr *hdr)
	311	{
	312	}
	313
	314	static void sfree_check_redzone(struct block_hdr *hdr)
	315	{
	316	}
	317	#endif
	318
	319	static void sfree_pool(struct pool pool, void ptr)
	320	{
	321	struct block_hdr *hdr;
	322	unsigned int i, idx;
	323	unsigned long offset;
	324
	325	if (!ptr)
	326	return;
	327
	328	ptr -= sizeof(*hdr);
	329	hdr = ptr;
	330
	331	assert(ptr_valid(pool, ptr));
	332
	333	sfree_check_redzone(hdr);
	334
	335	offset = ptr - pool->map;
	336	i = offset / SMALLOC_BPL;
	337	idx = (offset % SMALLOC_BPL) / SMALLOC_BPB;
	338
	339	pool_lock(pool);
	340	clear_blocks(pool, i, idx, size_to_blocks(hdr->size));
	341	if (i < pool->next_non_full)
	342	pool->next_non_full = i;
	343	pool->free_blocks += size_to_blocks(hdr->size);
	344	pool_unlock(pool);
	345	}
	346
	347	void sfree(void *ptr)
	348	{
	349	struct pool *pool = NULL;
	350	unsigned int i;
	351
	352	if (!ptr)
	353	return;
	354
	355	global_read_lock();
	356
	357	for (i = 0; i < nr_pools; i++) {
	358	if (ptr_valid(&mp[i], ptr)) {
	359	pool = &mp[i];
	360	break;
	361	}
	362	}
	363
	364	global_read_unlock();
	365
	366	if (pool) {
	367	sfree_pool(pool, ptr);
	368	return;
	369	}
	370
	371	log_err("smalloc: ptr %p not from smalloc pool\n", ptr);
	372	}
	373
	374	static void __smalloc_pool(struct pool pool, size_t size)
	375	{
	376	size_t nr_blocks;
	377	unsigned int i;
	378	unsigned int offset;
	379	unsigned int last_idx;
	380	void *ret = NULL;
	381
	382	pool_lock(pool);
	383
	384	nr_blocks = size_to_blocks(size);
	385	if (nr_blocks > pool->free_blocks)
	386	goto fail;
	387
	388	i = pool->next_non_full;
	389	last_idx = 0;
	390	offset = -1U;
	391	while (i < pool->nr_blocks) {
	392	unsigned int idx;
	393
	394	if (pool->bitmap[i] == -1U) {
	395	i++;
	396	pool->next_non_full = i;
	397	last_idx = 0;
	398	continue;
	399	}
	400
	401	idx = find_next_zero(pool->bitmap[i], last_idx);
	402	if (!blocks_free(pool, i, idx, nr_blocks)) {
	403	idx += nr_blocks;
	404	if (idx < SMALLOC_BPI)
	405	last_idx = idx;
	406	else {
	407	last_idx = 0;
	408	while (idx >= SMALLOC_BPI) {
	409	i++;
	410	idx -= SMALLOC_BPI;
	411	}
	412	}
	413	continue;
	414	}
	415	set_blocks(pool, i, idx, nr_blocks);
	416	offset = i * SMALLOC_BPL + idx * SMALLOC_BPB;
	417	break;
	418	}
	419
	420	if (i < pool->nr_blocks) {
	421	pool->free_blocks -= nr_blocks;
	422	ret = pool->map + offset;
	423	}
	424	fail:
	425	pool_unlock(pool);
	426	return ret;
	427	}
	428
	429	static void smalloc_pool(struct pool pool, size_t size)
	430	{
	431	size_t alloc_size = size + sizeof(struct block_hdr);
	432	void *ptr;
	433
	434	/*
	435	* Round to int alignment, so that the postred pointer will
	436	* be naturally aligned as well.
	437	*/
	438	#ifdef SMALLOC_REDZONE
	439	alloc_size += sizeof(unsigned int);
	440	alloc_size = (alloc_size + int_mask) & ~int_mask;
	441	#endif
	442
	443	ptr = __smalloc_pool(pool, alloc_size);
	444	if (ptr) {
	445	struct block_hdr *hdr = ptr;
	446
	447	hdr->size = alloc_size;
	448	fill_redzone(hdr);
	449
	450	ptr += sizeof(*hdr);
	451	memset(ptr, 0, size);
	452	}
	453
	454	return ptr;
	455	}
	456
	457	void *smalloc(size_t size)
	458	{
	459	unsigned int i, end_pool;
	460
	461	if (size != (unsigned int) size)
	462	return NULL;
	463
	464	global_write_lock();
	465	i = last_pool;
	466	end_pool = nr_pools;
	467
	468	do {
	469	for (; i < end_pool; i++) {
	470	void *ptr = smalloc_pool(&mp[i], size);
	471
	472	if (ptr) {
	473	last_pool = i;
	474	global_write_unlock();
	475	return ptr;
	476	}
	477	}
	478	if (last_pool) {
	479	end_pool = last_pool;
	480	last_pool = i = 0;
	481	continue;
	482	}
	483
	484	break;
	485	} while (1);
	486
	487	global_write_unlock();
	488	return NULL;
	489	}
	490
	491	void *scalloc(size_t nmemb, size_t size)
	492	{
	493	void *ret;
	494
	495	ret = smalloc(nmemb * size);
	496	if (ret)
	497	memset(ret, 0, nmemb * size);
	498
	499	return ret;
	500	}
	501
	502	char smalloc_strdup(const char str)
	503	{
	504	char *ptr = NULL;
	505
	506	ptr = smalloc(strlen(str) + 1);
	507	if (ptr)
	508	strcpy(ptr, str);
	509	return ptr;
	510	}