[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;
#ifdef SMALLOC_REDZONE
static const int int_mask = sizeof(int) - 1;
#endif

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)
{
	return smalloc(nmemb * size);
}

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	#ifdef SMALLOC_REDZONE
	36	static const int int_mask = sizeof(int) - 1;
	37	#endif
	38
	39	struct pool {
	40	struct fio_mutex lock; / protects this pool */
	41	void map; / map of blocks */
	42	unsigned int bitmap; / blocks free/busy map */
	43	size_t free_blocks; /* free blocks */
	44	size_t nr_blocks; /* total blocks */
	45	size_t next_non_full;
	46	size_t mmap_size;
	47	};
	48
	49	struct block_hdr {
	50	size_t size;
	51	#ifdef SMALLOC_REDZONE
	52	unsigned int prered;
	53	#endif
	54	};
	55
	56	static struct pool mp[MAX_POOLS];
	57	static unsigned int nr_pools;
	58	static unsigned int last_pool;
	59	static struct fio_rwlock *lock;
	60
	61	static inline void pool_lock(struct pool *pool)
	62	{
	63	fio_mutex_down(pool->lock);
	64	}
	65
	66	static inline void pool_unlock(struct pool *pool)
	67	{
	68	fio_mutex_up(pool->lock);
	69	}
	70
	71	static inline void global_read_lock(void)
	72	{
	73	fio_rwlock_read(lock);
	74	}
	75
	76	static inline void global_read_unlock(void)
	77	{
	78	fio_rwlock_unlock(lock);
	79	}
	80
	81	static inline void global_write_lock(void)
	82	{
	83	fio_rwlock_write(lock);
	84	}
	85
	86	static inline void global_write_unlock(void)
	87	{
	88	fio_rwlock_unlock(lock);
	89	}
	90
	91	static inline int ptr_valid(struct pool pool, void ptr)
	92	{
	93	unsigned int pool_size = pool->nr_blocks * SMALLOC_BPL;
	94
	95	return (ptr >= pool->map) && (ptr < pool->map + pool_size);
	96	}
	97
	98	static inline size_t size_to_blocks(size_t size)
	99	{
	100	return (size + SMALLOC_BPB - 1) / SMALLOC_BPB;
	101	}
	102
	103	static int blocks_iter(struct pool *pool, unsigned int pool_idx,
	104	unsigned int idx, size_t nr_blocks,
	105	int (func)(unsigned int map, unsigned int mask))
	106	{
	107
	108	while (nr_blocks) {
	109	unsigned int this_blocks, mask;
	110	unsigned int *map;
	111
	112	if (pool_idx >= pool->nr_blocks)
	113	return 0;
	114
	115	map = &pool->bitmap[pool_idx];
	116
	117	this_blocks = nr_blocks;
	118	if (this_blocks + idx > SMALLOC_BPI) {
	119	this_blocks = SMALLOC_BPI - idx;
	120	idx = SMALLOC_BPI - this_blocks;
	121	}
	122
	123	if (this_blocks == SMALLOC_BPI)
	124	mask = -1U;
	125	else
	126	mask = ((1U << this_blocks) - 1) << idx;
	127
	128	if (!func(map, mask))
	129	return 0;
	130
	131	nr_blocks -= this_blocks;
	132	idx = 0;
	133	pool_idx++;
	134	}
	135
	136	return 1;
	137	}
	138
	139	static int mask_cmp(unsigned int *map, unsigned int mask)
	140	{
	141	return !(*map & mask);
	142	}
	143
	144	static int mask_clear(unsigned int *map, unsigned int mask)
	145	{
	146	assert((*map & mask) == mask);
	147	*map &= ~mask;
	148	return 1;
	149	}
	150
	151	static int mask_set(unsigned int *map, unsigned int mask)
	152	{
	153	assert(!(*map & mask));
	154	*map \|= mask;
	155	return 1;
	156	}
	157
	158	static int blocks_free(struct pool *pool, unsigned int pool_idx,
	159	unsigned int idx, size_t nr_blocks)
	160	{
	161	return blocks_iter(pool, pool_idx, idx, nr_blocks, mask_cmp);
	162	}
	163
	164	static void set_blocks(struct pool *pool, unsigned int pool_idx,
	165	unsigned int idx, size_t nr_blocks)
	166	{
	167	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_set);
	168	}
	169
	170	static void clear_blocks(struct pool *pool, unsigned int pool_idx,
	171	unsigned int idx, size_t nr_blocks)
	172	{
	173	blocks_iter(pool, pool_idx, idx, nr_blocks, mask_clear);
	174	}
	175
	176	static int find_next_zero(int word, int start)
	177	{
	178	assert(word != -1U);
	179	word >>= start;
	180	return ffz(word) + start;
	181	}
	182
	183	static int add_pool(struct pool *pool, unsigned int alloc_size)
	184	{
	185	int bitmap_blocks;
	186	int mmap_flags;
	187	void *ptr;
	188
	189	#ifdef SMALLOC_REDZONE
	190	alloc_size += sizeof(unsigned int);
	191	#endif
	192	alloc_size += sizeof(struct block_hdr);
	193	if (alloc_size < INITIAL_SIZE)
	194	alloc_size = INITIAL_SIZE;
	195
	196	/* round up to nearest full number of blocks */
	197	alloc_size = (alloc_size + SMALLOC_BPL - 1) & ~(SMALLOC_BPL - 1);
	198	bitmap_blocks = alloc_size / SMALLOC_BPL;
	199	alloc_size += bitmap_blocks * sizeof(unsigned int);
	200	pool->mmap_size = alloc_size;
	201
	202	pool->nr_blocks = bitmap_blocks;
	203	pool->free_blocks = bitmap_blocks * SMALLOC_BPB;
	204
	205	mmap_flags = OS_MAP_ANON;
	206	#ifdef CONFIG_ESX
	207	mmap_flags \|= MAP_PRIVATE;
	208	#else
	209	mmap_flags \|= MAP_SHARED;
	210	#endif
	211	ptr = mmap(NULL, alloc_size, PROT_READ\|PROT_WRITE, mmap_flags, -1, 0);
	212
	213	if (ptr == MAP_FAILED)
	214	goto out_fail;
	215
	216	memset(ptr, 0, alloc_size);
	217	pool->map = ptr;
	218	pool->bitmap = (void ) ptr + (pool->nr_blocks SMALLOC_BPL);
	219
	220	pool->lock = fio_mutex_init(FIO_MUTEX_UNLOCKED);
	221	if (!pool->lock)
	222	goto out_fail;
	223
	224	nr_pools++;
	225	return 0;
	226	out_fail:
	227	log_err("smalloc: failed adding pool\n");
	228	if (pool->map)
	229	munmap(pool->map, pool->mmap_size);
	230	return 1;
	231	}
	232
	233	void sinit(void)
	234	{
	235	int i, ret;
	236
	237	lock = fio_rwlock_init();
	238
	239	for (i = 0; i < MAX_POOLS; i++) {
	240	ret = add_pool(&mp[i], INITIAL_SIZE);
	241	if (ret)
	242	break;
	243	}
	244
	245	/*
	246	* If we added at least one pool, we should be OK for most
	247	* cases.
	248	*/
	249	assert(i);
	250	}
	251
	252	static void cleanup_pool(struct pool *pool)
	253	{
	254	/*
	255	* This will also remove the temporary file we used as a backing
	256	* store, it was already unlinked
	257	*/
	258	munmap(pool->map, pool->mmap_size);
	259
	260	if (pool->lock)
	261	fio_mutex_remove(pool->lock);
	262	}
	263
	264	void scleanup(void)
	265	{
	266	unsigned int i;
	267
	268	for (i = 0; i < nr_pools; i++)
	269	cleanup_pool(&mp[i]);
	270
	271	if (lock)
	272	fio_rwlock_remove(lock);
	273	}
	274
	275	#ifdef SMALLOC_REDZONE
	276	static void postred_ptr(struct block_hdr hdr)
	277	{
	278	uintptr_t ptr;
	279
	280	ptr = (uintptr_t) hdr + hdr->size - sizeof(unsigned int);
	281	ptr = (ptr + int_mask) & ~int_mask;
	282
	283	return (void *) ptr;
	284	}
	285
	286	static void fill_redzone(struct block_hdr *hdr)
	287	{
	288	unsigned int *postred = postred_ptr(hdr);
	289
	290	hdr->prered = SMALLOC_PRE_RED;
	291	*postred = SMALLOC_POST_RED;
	292	}
	293
	294	static void sfree_check_redzone(struct block_hdr *hdr)
	295	{
	296	unsigned int *postred = postred_ptr(hdr);
	297
	298	if (hdr->prered != SMALLOC_PRE_RED) {
	299	log_err("smalloc pre redzone destroyed!\n"
	300	" ptr=%p, prered=%x, expected %x\n",
	301	hdr, hdr->prered, SMALLOC_PRE_RED);
	302	assert(0);
	303	}
	304	if (*postred != SMALLOC_POST_RED) {
	305	log_err("smalloc post redzone destroyed!\n"
	306	" ptr=%p, postred=%x, expected %x\n",
	307	hdr, *postred, SMALLOC_POST_RED);
	308	assert(0);
	309	}
	310	}
	311	#else
	312	static void fill_redzone(struct block_hdr *hdr)
	313	{
	314	}
	315
	316	static void sfree_check_redzone(struct block_hdr *hdr)
	317	{
	318	}
	319	#endif
	320
	321	static void sfree_pool(struct pool pool, void ptr)
	322	{
	323	struct block_hdr *hdr;
	324	unsigned int i, idx;
	325	unsigned long offset;
	326
	327	if (!ptr)
	328	return;
	329
	330	ptr -= sizeof(*hdr);
	331	hdr = ptr;
	332
	333	assert(ptr_valid(pool, ptr));
	334
	335	sfree_check_redzone(hdr);
	336
	337	offset = ptr - pool->map;
	338	i = offset / SMALLOC_BPL;
	339	idx = (offset % SMALLOC_BPL) / SMALLOC_BPB;
	340
	341	pool_lock(pool);
	342	clear_blocks(pool, i, idx, size_to_blocks(hdr->size));
	343	if (i < pool->next_non_full)
	344	pool->next_non_full = i;
	345	pool->free_blocks += size_to_blocks(hdr->size);
	346	pool_unlock(pool);
	347	}
	348
	349	void sfree(void *ptr)
	350	{
	351	struct pool *pool = NULL;
	352	unsigned int i;
	353
	354	if (!ptr)
	355	return;
	356
	357	global_read_lock();
	358
	359	for (i = 0; i < nr_pools; i++) {
	360	if (ptr_valid(&mp[i], ptr)) {
	361	pool = &mp[i];
	362	break;
	363	}
	364	}
	365
	366	global_read_unlock();
	367
	368	if (pool) {
	369	sfree_pool(pool, ptr);
	370	return;
	371	}
	372
	373	log_err("smalloc: ptr %p not from smalloc pool\n", ptr);
	374	}
	375
	376	static void __smalloc_pool(struct pool pool, size_t size)
	377	{
	378	size_t nr_blocks;
	379	unsigned int i;
	380	unsigned int offset;
	381	unsigned int last_idx;
	382	void *ret = NULL;
	383
	384	pool_lock(pool);
	385
	386	nr_blocks = size_to_blocks(size);
	387	if (nr_blocks > pool->free_blocks)
	388	goto fail;
	389
	390	i = pool->next_non_full;
	391	last_idx = 0;
	392	offset = -1U;
	393	while (i < pool->nr_blocks) {
	394	unsigned int idx;
	395
	396	if (pool->bitmap[i] == -1U) {
	397	i++;
	398	pool->next_non_full = i;
	399	last_idx = 0;
	400	continue;
	401	}
	402
	403	idx = find_next_zero(pool->bitmap[i], last_idx);
	404	if (!blocks_free(pool, i, idx, nr_blocks)) {
	405	idx += nr_blocks;
	406	if (idx < SMALLOC_BPI)
	407	last_idx = idx;
	408	else {
	409	last_idx = 0;
	410	while (idx >= SMALLOC_BPI) {
	411	i++;
	412	idx -= SMALLOC_BPI;
	413	}
	414	}
	415	continue;
	416	}
	417	set_blocks(pool, i, idx, nr_blocks);
	418	offset = i * SMALLOC_BPL + idx * SMALLOC_BPB;
	419	break;
	420	}
	421
	422	if (i < pool->nr_blocks) {
	423	pool->free_blocks -= nr_blocks;
	424	ret = pool->map + offset;
	425	}
	426	fail:
	427	pool_unlock(pool);
	428	return ret;
	429	}
	430
	431	static void smalloc_pool(struct pool pool, size_t size)
	432	{
	433	size_t alloc_size = size + sizeof(struct block_hdr);
	434	void *ptr;
	435
	436	/*
	437	* Round to int alignment, so that the postred pointer will
	438	* be naturally aligned as well.
	439	*/
	440	#ifdef SMALLOC_REDZONE
	441	alloc_size += sizeof(unsigned int);
	442	alloc_size = (alloc_size + int_mask) & ~int_mask;
	443	#endif
	444
	445	ptr = __smalloc_pool(pool, alloc_size);
	446	if (ptr) {
	447	struct block_hdr *hdr = ptr;
	448
	449	hdr->size = alloc_size;
	450	fill_redzone(hdr);
	451
	452	ptr += sizeof(*hdr);
	453	memset(ptr, 0, size);
	454	}
	455
	456	return ptr;
	457	}
	458
	459	void *smalloc(size_t size)
	460	{
	461	unsigned int i, end_pool;
	462
	463	if (size != (unsigned int) size)
	464	return NULL;
	465
	466	global_write_lock();
	467	i = last_pool;
	468	end_pool = nr_pools;
	469
	470	do {
	471	for (; i < end_pool; i++) {
	472	void *ptr = smalloc_pool(&mp[i], size);
	473
	474	if (ptr) {
	475	last_pool = i;
	476	global_write_unlock();
	477	return ptr;
	478	}
	479	}
	480	if (last_pool) {
	481	end_pool = last_pool;
	482	last_pool = i = 0;
	483	continue;
	484	}
	485
	486	break;
	487	} while (1);
	488
	489	global_write_unlock();
	490	return NULL;
	491	}
	492
	493	void *scalloc(size_t nmemb, size_t size)
	494	{
	495	return smalloc(nmemb * size);
	496	}
	497
	498	char smalloc_strdup(const char str)
	499	{
	500	char *ptr = NULL;
	501
	502	ptr = smalloc(strlen(str) + 1);
	503	if (ptr)
	504	strcpy(ptr, str);
	505	return ptr;
	506	}