[linux-2.6-block.git] / lib / sg_pool.c

#include <linux/module.h>
#include <linux/scatterlist.h>
#include <linux/mempool.h>
#include <linux/slab.h>

#define SG_MEMPOOL_NR		ARRAY_SIZE(sg_pools)
#define SG_MEMPOOL_SIZE		2

struct sg_pool {
	size_t		size;
	char		*name;
	struct kmem_cache	*slab;
	mempool_t	*pool;
};

#define SP(x) { .size = x, "sgpool-" __stringify(x) }
#if (SG_CHUNK_SIZE < 32)
#error SG_CHUNK_SIZE is too small (must be 32 or greater)
#endif
static struct sg_pool sg_pools[] = {
	SP(8),
	SP(16),
#if (SG_CHUNK_SIZE > 32)
	SP(32),
#if (SG_CHUNK_SIZE > 64)
	SP(64),
#if (SG_CHUNK_SIZE > 128)
	SP(128),
#if (SG_CHUNK_SIZE > 256)
#error SG_CHUNK_SIZE is too large (256 MAX)
#endif
#endif
#endif
#endif
	SP(SG_CHUNK_SIZE)
};
#undef SP

static inline unsigned int sg_pool_index(unsigned short nents)
{
	unsigned int index;

	BUG_ON(nents > SG_CHUNK_SIZE);

	if (nents <= 8)
		index = 0;
	else
		index = get_count_order(nents) - 3;

	return index;
}

static void sg_pool_free(struct scatterlist *sgl, unsigned int nents)
{
	struct sg_pool *sgp;

	sgp = sg_pools + sg_pool_index(nents);
	mempool_free(sgl, sgp->pool);
}

static struct scatterlist *sg_pool_alloc(unsigned int nents, gfp_t gfp_mask)
{
	struct sg_pool *sgp;

	sgp = sg_pools + sg_pool_index(nents);
	return mempool_alloc(sgp->pool, gfp_mask);
}

/**
 * sg_free_table_chained - Free a previously mapped sg table
 * @table:	The sg table header to use
 * @nents_first_chunk: size of the first_chunk SGL passed to
 *		sg_alloc_table_chained
 *
 *  Description:
 *    Free an sg table previously allocated and setup with
 *    sg_alloc_table_chained().
 *
 *    @nents_first_chunk has to be same with that same parameter passed
 *    to sg_alloc_table_chained().
 *
 **/
void sg_free_table_chained(struct sg_table *table,
		unsigned nents_first_chunk)
{
	if (table->orig_nents <= nents_first_chunk)
		return;

	if (nents_first_chunk == 1)
		nents_first_chunk = 0;

	__sg_free_table(table, SG_CHUNK_SIZE, nents_first_chunk, sg_pool_free);
}
EXPORT_SYMBOL_GPL(sg_free_table_chained);

/**
 * sg_alloc_table_chained - Allocate and chain SGLs in an sg table
 * @table:	The sg table header to use
 * @nents:	Number of entries in sg list
 * @first_chunk: first SGL
 * @nents_first_chunk: number of the SGL of @first_chunk
 *
 *  Description:
 *    Allocate and chain SGLs in an sg table. If @nents@ is larger than
 *    @nents_first_chunk a chained sg table will be setup.
 *
 **/
int sg_alloc_table_chained(struct sg_table *table, int nents,
		struct scatterlist *first_chunk, unsigned nents_first_chunk)
{
	int ret;

	BUG_ON(!nents);

	if (first_chunk && nents_first_chunk) {
		if (nents <= nents_first_chunk) {
			table->nents = table->orig_nents = nents;
			sg_init_table(table->sgl, nents);
			return 0;
		}
	}

	/* User supposes that the 1st SGL includes real entry */
	if (nents_first_chunk == 1) {
		first_chunk = NULL;
		nents_first_chunk = 0;
	}

	ret = __sg_alloc_table(table, nents, SG_CHUNK_SIZE,
			       first_chunk, nents_first_chunk,
			       GFP_ATOMIC, sg_pool_alloc);
	if (unlikely(ret))
		sg_free_table_chained(table, nents_first_chunk);
	return ret;
}
EXPORT_SYMBOL_GPL(sg_alloc_table_chained);

static __init int sg_pool_init(void)
{
	int i;

	for (i = 0; i < SG_MEMPOOL_NR; i++) {
		struct sg_pool *sgp = sg_pools + i;
		int size = sgp->size * sizeof(struct scatterlist);

		sgp->slab = kmem_cache_create(sgp->name, size, 0,
				SLAB_HWCACHE_ALIGN, NULL);
		if (!sgp->slab) {
			printk(KERN_ERR "SG_POOL: can't init sg slab %s\n",
					sgp->name);
			goto cleanup_sdb;
		}

		sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
						     sgp->slab);
		if (!sgp->pool) {
			printk(KERN_ERR "SG_POOL: can't init sg mempool %s\n",
					sgp->name);
			goto cleanup_sdb;
		}
	}

	return 0;

cleanup_sdb:
	for (i = 0; i < SG_MEMPOOL_NR; i++) {
		struct sg_pool *sgp = sg_pools + i;

		mempool_destroy(sgp->pool);
		kmem_cache_destroy(sgp->slab);
	}

	return -ENOMEM;
}

static __exit void sg_pool_exit(void)
{
	int i;

	for (i = 0; i < SG_MEMPOOL_NR; i++) {
		struct sg_pool *sgp = sg_pools + i;
		mempool_destroy(sgp->pool);
		kmem_cache_destroy(sgp->slab);
	}
}

module_init(sg_pool_init);
module_exit(sg_pool_exit);
Commit	Line	Data
9b1d6c89 ML	1	#include <linux/module.h>
	2	#include <linux/scatterlist.h>
	3	#include <linux/mempool.h>
	4	#include <linux/slab.h>
	5
	6	#define SG_MEMPOOL_NR ARRAY_SIZE(sg_pools)
	7	#define SG_MEMPOOL_SIZE 2
	8
	9	struct sg_pool {
	10	size_t size;
	11	char *name;
	12	struct kmem_cache *slab;
	13	mempool_t *pool;
	14	};
	15
	16	#define SP(x) { .size = x, "sgpool-" __stringify(x) }
	17	#if (SG_CHUNK_SIZE < 32)
	18	#error SG_CHUNK_SIZE is too small (must be 32 or greater)
	19	#endif
	20	static struct sg_pool sg_pools[] = {
	21	SP(8),
	22	SP(16),
	23	#if (SG_CHUNK_SIZE > 32)
	24	SP(32),
	25	#if (SG_CHUNK_SIZE > 64)
	26	SP(64),
	27	#if (SG_CHUNK_SIZE > 128)
	28	SP(128),
	29	#if (SG_CHUNK_SIZE > 256)
	30	#error SG_CHUNK_SIZE is too large (256 MAX)
	31	#endif
	32	#endif
	33	#endif
	34	#endif
	35	SP(SG_CHUNK_SIZE)
	36	};
	37	#undef SP
	38
	39	static inline unsigned int sg_pool_index(unsigned short nents)
	40	{
	41	unsigned int index;
	42
	43	BUG_ON(nents > SG_CHUNK_SIZE);
	44
	45	if (nents <= 8)
	46	index = 0;
	47	else
	48	index = get_count_order(nents) - 3;
	49
	50	return index;
	51	}
	52
	53	static void sg_pool_free(struct scatterlist *sgl, unsigned int nents)
	54	{
	55	struct sg_pool *sgp;
	56
	57	sgp = sg_pools + sg_pool_index(nents);
	58	mempool_free(sgl, sgp->pool);
	59	}
	60
	61	static struct scatterlist *sg_pool_alloc(unsigned int nents, gfp_t gfp_mask)
	62	{
	63	struct sg_pool *sgp;
	64
65	sgp = sg_pools + sg_pool_index(nents);
66	return mempool_alloc(sgp->pool, gfp_mask);
67	}
68
69	/**
70	* sg_free_table_chained - Free a previously mapped sg table
71	* @table: The sg table header to use
4635873c ML	72	* @nents_first_chunk: size of the first_chunk SGL passed to
4635873c ML	73	* sg_alloc_table_chained
9b1d6c89 ML	74	*
	75	* Description:
	76	* Free an sg table previously allocated and setup with
	77	* sg_alloc_table_chained().
	78	*
4635873c ML	79	* @nents_first_chunk has to be same with that same parameter passed
	80	* to sg_alloc_table_chained().
	81	*
9b1d6c89	82	**/
4635873c ML	83	void sg_free_table_chained(struct sg_table *table,
4635873c ML	84	unsigned nents_first_chunk)
9b1d6c89	85	{
4635873c	86	if (table->orig_nents <= nents_first_chunk)
9b1d6c89	87	return;
4635873c ML	88
	89	if (nents_first_chunk == 1)
	90	nents_first_chunk = 0;
	91
	92	__sg_free_table(table, SG_CHUNK_SIZE, nents_first_chunk, sg_pool_free);
9b1d6c89 ML	93	}
	94	EXPORT_SYMBOL_GPL(sg_free_table_chained);
	95
	96	/**
	97	* sg_alloc_table_chained - Allocate and chain SGLs in an sg table
	98	* @table: The sg table header to use
	99	* @nents: Number of entries in sg list
	100	* @first_chunk: first SGL
4635873c	101	* @nents_first_chunk: number of the SGL of @first_chunk
9b1d6c89 ML	102	*
	103	* Description:
	104	* Allocate and chain SGLs in an sg table. If @nents@ is larger than
4635873c	105	* @nents_first_chunk a chained sg table will be setup.
9b1d6c89 ML	106	*
	107	**/
	108	int sg_alloc_table_chained(struct sg_table *table, int nents,
4635873c	109	struct scatterlist *first_chunk, unsigned nents_first_chunk)
9b1d6c89 ML	110	{
	111	int ret;
	112
	113	BUG_ON(!nents);
	114
4635873c ML	115	if (first_chunk && nents_first_chunk) {
4635873c ML	116	if (nents <= nents_first_chunk) {
9b1d6c89 ML	117	table->nents = table->orig_nents = nents;
	118	sg_init_table(table->sgl, nents);
	119	return 0;
	120	}
	121	}
	122
4635873c ML	123	/* User supposes that the 1st SGL includes real entry */
	124	if (nents_first_chunk == 1) {
	125	first_chunk = NULL;
	126	nents_first_chunk = 0;
	127	}
	128
9b1d6c89	129	ret = __sg_alloc_table(table, nents, SG_CHUNK_SIZE,
4635873c ML	130	first_chunk, nents_first_chunk,
4635873c ML	131	GFP_ATOMIC, sg_pool_alloc);
9b1d6c89	132	if (unlikely(ret))
4635873c	133	sg_free_table_chained(table, nents_first_chunk);
9b1d6c89 ML	134	return ret;
	135	}
	136	EXPORT_SYMBOL_GPL(sg_alloc_table_chained);
	137
	138	static __init int sg_pool_init(void)
	139	{
	140	int i;
	141
	142	for (i = 0; i < SG_MEMPOOL_NR; i++) {
	143	struct sg_pool *sgp = sg_pools + i;
	144	int size = sgp->size * sizeof(struct scatterlist);
	145
	146	sgp->slab = kmem_cache_create(sgp->name, size, 0,
	147	SLAB_HWCACHE_ALIGN, NULL);
	148	if (!sgp->slab) {
	149	printk(KERN_ERR "SG_POOL: can't init sg slab %s\n",
	150	sgp->name);
	151	goto cleanup_sdb;
	152	}
	153
	154	sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
	155	sgp->slab);
	156	if (!sgp->pool) {
	157	printk(KERN_ERR "SG_POOL: can't init sg mempool %s\n",
	158	sgp->name);
	159	goto cleanup_sdb;
	160	}
	161	}
	162
	163	return 0;
	164
	165	cleanup_sdb:
	166	for (i = 0; i < SG_MEMPOOL_NR; i++) {
	167	struct sg_pool *sgp = sg_pools + i;
7f476715	168
	169	mempool_destroy(sgp->pool);
	170	kmem_cache_destroy(sgp->slab);
9b1d6c89 ML	171	}
	172
	173	return -ENOMEM;
	174	}
	175
	176	static __exit void sg_pool_exit(void)
	177	{
	178	int i;
	179
	180	for (i = 0; i < SG_MEMPOOL_NR; i++) {
	181	struct sg_pool *sgp = sg_pools + i;
	182	mempool_destroy(sgp->pool);
	183	kmem_cache_destroy(sgp->slab);
	184	}
	185	}
	186
	187	module_init(sg_pool_init);
	188	module_exit(sg_pool_exit);