[linux.git] / lib / sg_pool.c

// SPDX-License-Identifier: GPL-2.0-only
#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,
			table->orig_nents);
}
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. @first_chunk is
 *    ignored if nents_first_chunk <= 1 because user expects the SGL points
 *    non-chain SGL.
 *
 **/
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
457c8996	1	// SPDX-License-Identifier: GPL-2.0-only
9b1d6c89 ML	2	#include <linux/module.h>
	3	#include <linux/scatterlist.h>
	4	#include <linux/mempool.h>
	5	#include <linux/slab.h>
	6
	7	#define SG_MEMPOOL_NR ARRAY_SIZE(sg_pools)
	8	#define SG_MEMPOOL_SIZE 2
	9
	10	struct sg_pool {
	11	size_t size;
	12	char *name;
	13	struct kmem_cache *slab;
	14	mempool_t *pool;
	15	};
	16
	17	#define SP(x) { .size = x, "sgpool-" __stringify(x) }
	18	#if (SG_CHUNK_SIZE < 32)
	19	#error SG_CHUNK_SIZE is too small (must be 32 or greater)
	20	#endif
	21	static struct sg_pool sg_pools[] = {
	22	SP(8),
	23	SP(16),
	24	#if (SG_CHUNK_SIZE > 32)
	25	SP(32),
	26	#if (SG_CHUNK_SIZE > 64)
	27	SP(64),
	28	#if (SG_CHUNK_SIZE > 128)
	29	SP(128),
	30	#if (SG_CHUNK_SIZE > 256)
	31	#error SG_CHUNK_SIZE is too large (256 MAX)
	32	#endif
	33	#endif
	34	#endif
	35	#endif
	36	SP(SG_CHUNK_SIZE)
	37	};
	38	#undef SP
	39
	40	static inline unsigned int sg_pool_index(unsigned short nents)
	41	{
	42	unsigned int index;
	43
	44	BUG_ON(nents > SG_CHUNK_SIZE);
	45
	46	if (nents <= 8)
	47	index = 0;
	48	else
	49	index = get_count_order(nents) - 3;
	50
	51	return index;
	52	}
	53
	54	static void sg_pool_free(struct scatterlist *sgl, unsigned int nents)
	55	{
	56	struct sg_pool *sgp;
	57
	58	sgp = sg_pools + sg_pool_index(nents);
	59	mempool_free(sgl, sgp->pool);
	60	}
	61
	62	static struct scatterlist *sg_pool_alloc(unsigned int nents, gfp_t gfp_mask)
	63	{
	64	struct sg_pool *sgp;
	65
66	sgp = sg_pools + sg_pool_index(nents);
67	return mempool_alloc(sgp->pool, gfp_mask);
68	}
69
70	/**
71	* sg_free_table_chained - Free a previously mapped sg table
72	* @table: The sg table header to use
4635873c ML	73	* @nents_first_chunk: size of the first_chunk SGL passed to
4635873c ML	74	* sg_alloc_table_chained
9b1d6c89 ML	75	*
	76	* Description:
	77	* Free an sg table previously allocated and setup with
	78	* sg_alloc_table_chained().
	79	*
4635873c ML	80	* @nents_first_chunk has to be same with that same parameter passed
	81	* to sg_alloc_table_chained().
	82	*
9b1d6c89	83	**/
4635873c ML	84	void sg_free_table_chained(struct sg_table *table,
4635873c ML	85	unsigned nents_first_chunk)
9b1d6c89	86	{
4635873c	87	if (table->orig_nents <= nents_first_chunk)
9b1d6c89	88	return;
4635873c ML	89
	90	if (nents_first_chunk == 1)
	91	nents_first_chunk = 0;
	92
3e302dbc MG	93	__sg_free_table(table, SG_CHUNK_SIZE, nents_first_chunk, sg_pool_free,
3e302dbc MG	94	table->orig_nents);
9b1d6c89 ML	95	}
	96	EXPORT_SYMBOL_GPL(sg_free_table_chained);
	97
	98	/**
	99	* sg_alloc_table_chained - Allocate and chain SGLs in an sg table
	100	* @table: The sg table header to use
	101	* @nents: Number of entries in sg list
	102	* @first_chunk: first SGL
4635873c	103	* @nents_first_chunk: number of the SGL of @first_chunk
9b1d6c89 ML	104	*
	105	* Description:
	106	* Allocate and chain SGLs in an sg table. If @nents@ is larger than
b79d9a09 ML	107	* @nents_first_chunk a chained sg table will be setup. @first_chunk is
	108	* ignored if nents_first_chunk <= 1 because user expects the SGL points
	109	* non-chain SGL.
9b1d6c89 ML	110	*
	111	**/
	112	int sg_alloc_table_chained(struct sg_table *table, int nents,
4635873c	113	struct scatterlist *first_chunk, unsigned nents_first_chunk)
9b1d6c89 ML	114	{
	115	int ret;
	116
	117	BUG_ON(!nents);
	118
4635873c ML	119	if (first_chunk && nents_first_chunk) {
4635873c ML	120	if (nents <= nents_first_chunk) {
9b1d6c89 ML	121	table->nents = table->orig_nents = nents;
	122	sg_init_table(table->sgl, nents);
	123	return 0;
	124	}
	125	}
	126
4635873c	127	/* User supposes that the 1st SGL includes real entry */
b79d9a09	128	if (nents_first_chunk <= 1) {
4635873c ML	129	first_chunk = NULL;
	130	nents_first_chunk = 0;
	131	}
	132
9b1d6c89	133	ret = __sg_alloc_table(table, nents, SG_CHUNK_SIZE,
4635873c ML	134	first_chunk, nents_first_chunk,
4635873c ML	135	GFP_ATOMIC, sg_pool_alloc);
9b1d6c89	136	if (unlikely(ret))
4635873c	137	sg_free_table_chained(table, nents_first_chunk);
9b1d6c89 ML	138	return ret;
	139	}
	140	EXPORT_SYMBOL_GPL(sg_alloc_table_chained);
	141
	142	static __init int sg_pool_init(void)
	143	{
	144	int i;
	145
	146	for (i = 0; i < SG_MEMPOOL_NR; i++) {
	147	struct sg_pool *sgp = sg_pools + i;
	148	int size = sgp->size * sizeof(struct scatterlist);
	149
	150	sgp->slab = kmem_cache_create(sgp->name, size, 0,
	151	SLAB_HWCACHE_ALIGN, NULL);
	152	if (!sgp->slab) {
	153	printk(KERN_ERR "SG_POOL: can't init sg slab %s\n",
	154	sgp->name);
	155	goto cleanup_sdb;
	156	}
	157
	158	sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
	159	sgp->slab);
	160	if (!sgp->pool) {
	161	printk(KERN_ERR "SG_POOL: can't init sg mempool %s\n",
	162	sgp->name);
	163	goto cleanup_sdb;
	164	}
	165	}
	166
	167	return 0;
	168
	169	cleanup_sdb:
	170	for (i = 0; i < SG_MEMPOOL_NR; i++) {
	171	struct sg_pool *sgp = sg_pools + i;
7f476715	172
	173	mempool_destroy(sgp->pool);
	174	kmem_cache_destroy(sgp->slab);
9b1d6c89 ML	175	}
	176
	177	return -ENOMEM;
	178	}
	179
	180	static __exit void sg_pool_exit(void)
	181	{
	182	int i;
	183
	184	for (i = 0; i < SG_MEMPOOL_NR; i++) {
	185	struct sg_pool *sgp = sg_pools + i;
	186	mempool_destroy(sgp->pool);
	187	kmem_cache_destroy(sgp->slab);
	188	}
	189	}
	190
	191	module_init(sg_pool_init);
	192	module_exit(sg_pool_exit);