mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2024-08-27 19:29:37 +00:00
![Ming Lin](/assets/img/avatar_default.png)
Now it's ready to move the mempool based SG chained allocator code from SCSI driver to lib/sg_pool.c, which will be compiled only based on a Kconfig symbol CONFIG_SG_POOL. SCSI selects CONFIG_SG_POOL. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Ming Lin <ming.l@ssi.samsung.com> Reviewed-by: Sagi Grimberg <sagi@grimberg.me> Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
172 lines
3.6 KiB
C
172 lines
3.6 KiB
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
|
|
* @first_chunk: was first_chunk not NULL in sg_alloc_table_chained?
|
|
*
|
|
* Description:
|
|
* Free an sg table previously allocated and setup with
|
|
* sg_alloc_table_chained().
|
|
*
|
|
**/
|
|
void sg_free_table_chained(struct sg_table *table, bool first_chunk)
|
|
{
|
|
if (first_chunk && table->orig_nents <= SG_CHUNK_SIZE)
|
|
return;
|
|
__sg_free_table(table, SG_CHUNK_SIZE, 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
|
|
*
|
|
* Description:
|
|
* Allocate and chain SGLs in an sg table. If @nents@ is larger than
|
|
* SG_CHUNK_SIZE a chained sg table will be setup.
|
|
*
|
|
**/
|
|
int sg_alloc_table_chained(struct sg_table *table, int nents,
|
|
struct scatterlist *first_chunk)
|
|
{
|
|
int ret;
|
|
|
|
BUG_ON(!nents);
|
|
|
|
if (first_chunk) {
|
|
if (nents <= SG_CHUNK_SIZE) {
|
|
table->nents = table->orig_nents = nents;
|
|
sg_init_table(table->sgl, nents);
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
ret = __sg_alloc_table(table, nents, SG_CHUNK_SIZE,
|
|
first_chunk, GFP_ATOMIC, sg_pool_alloc);
|
|
if (unlikely(ret))
|
|
sg_free_table_chained(table, (bool)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;
|
|
if (sgp->pool)
|
|
mempool_destroy(sgp->pool);
|
|
if (sgp->slab)
|
|
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);
|