lib: scatterlist: move SG pool code from SCSI driver to lib/sg_pool.c
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>
This commit is contained in:
Ming Lin
Martin K. Petersen
parent
65e8617fba
commit
9b1d6c8950
7 changed files with 206 additions and 156 deletions
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@ -17,6 +17,7 @@ config SCSI
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tristate "SCSI device support"
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depends on BLOCK
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select SCSI_DMA if HAS_DMA
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select SG_POOL
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---help---
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If you want to use a SCSI hard disk, SCSI tape drive, SCSI CD-ROM or
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any other SCSI device under Linux, say Y and make sure that you know
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@ -14,8 +14,6 @@
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#include <linux/completion.h>
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#include <linux/kernel.h>
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#include <linux/export.h>
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#include <linux/mempool.h>
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#include <linux/slab.h>
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#include <linux/init.h>
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#include <linux/pci.h>
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#include <linux/delay.h>
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@ -40,39 +38,6 @@
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#include "scsi_logging.h"
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#define SG_MEMPOOL_NR ARRAY_SIZE(sg_pools)
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#define SG_MEMPOOL_SIZE 2
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struct sg_pool {
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size_t size;
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char *name;
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struct kmem_cache *slab;
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mempool_t *pool;
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};
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#define SP(x) { .size = x, "sgpool-" __stringify(x) }
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#if (SG_CHUNK_SIZE < 32)
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#error SG_CHUNK_SIZE is too small (must be 32 or greater)
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#endif
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static struct sg_pool sg_pools[] = {
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SP(8),
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SP(16),
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#if (SG_CHUNK_SIZE > 32)
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SP(32),
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#if (SG_CHUNK_SIZE > 64)
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SP(64),
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#if (SG_CHUNK_SIZE > 128)
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SP(128),
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#if (SG_CHUNK_SIZE > 256)
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#error SG_CHUNK_SIZE is too large (256 MAX)
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#endif
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#endif
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#endif
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#endif
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SP(SG_CHUNK_SIZE)
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};
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#undef SP
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struct kmem_cache *scsi_sdb_cache;
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/*
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@ -553,65 +518,6 @@ void scsi_run_host_queues(struct Scsi_Host *shost)
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scsi_run_queue(sdev->request_queue);
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}
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static inline unsigned int sg_pool_index(unsigned short nents)
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{
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unsigned int index;
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BUG_ON(nents > SG_CHUNK_SIZE);
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if (nents <= 8)
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index = 0;
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else
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index = get_count_order(nents) - 3;
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return index;
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}
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static void sg_pool_free(struct scatterlist *sgl, unsigned int nents)
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{
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struct sg_pool *sgp;
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sgp = sg_pools + sg_pool_index(nents);
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mempool_free(sgl, sgp->pool);
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}
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static struct scatterlist *sg_pool_alloc(unsigned int nents, gfp_t gfp_mask)
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{
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struct sg_pool *sgp;
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sgp = sg_pools + sg_pool_index(nents);
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return mempool_alloc(sgp->pool, gfp_mask);
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}
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static void sg_free_table_chained(struct sg_table *table, bool first_chunk)
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{
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if (first_chunk && table->orig_nents <= SG_CHUNK_SIZE)
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return;
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__sg_free_table(table, SG_CHUNK_SIZE, first_chunk, sg_pool_free);
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}
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static int sg_alloc_table_chained(struct sg_table *table, int nents,
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struct scatterlist *first_chunk)
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{
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int ret;
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BUG_ON(!nents);
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if (first_chunk) {
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if (nents <= SG_CHUNK_SIZE) {
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table->nents = table->orig_nents = nents;
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sg_init_table(table->sgl, nents);
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return 0;
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}
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}
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ret = __sg_alloc_table(table, nents, SG_CHUNK_SIZE,
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first_chunk, GFP_ATOMIC, sg_pool_alloc);
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if (unlikely(ret))
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sg_free_table_chained(table, (bool)first_chunk);
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return ret;
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}
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static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
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{
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if (cmd->request->cmd_type == REQ_TYPE_FS) {
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@ -2269,8 +2175,6 @@ EXPORT_SYMBOL(scsi_unblock_requests);
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int __init scsi_init_queue(void)
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{
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int i;
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scsi_sdb_cache = kmem_cache_create("scsi_data_buffer",
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sizeof(struct scsi_data_buffer),
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0, 0, NULL);
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@ -2279,53 +2183,12 @@ int __init scsi_init_queue(void)
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return -ENOMEM;
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}
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for (i = 0; i < SG_MEMPOOL_NR; i++) {
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struct sg_pool *sgp = sg_pools + i;
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int size = sgp->size * sizeof(struct scatterlist);
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sgp->slab = kmem_cache_create(sgp->name, size, 0,
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SLAB_HWCACHE_ALIGN, NULL);
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if (!sgp->slab) {
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printk(KERN_ERR "SCSI: can't init sg slab %s\n",
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sgp->name);
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goto cleanup_sdb;
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}
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sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
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sgp->slab);
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if (!sgp->pool) {
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printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
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sgp->name);
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goto cleanup_sdb;
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}
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}
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return 0;
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cleanup_sdb:
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for (i = 0; i < SG_MEMPOOL_NR; i++) {
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struct sg_pool *sgp = sg_pools + i;
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if (sgp->pool)
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mempool_destroy(sgp->pool);
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if (sgp->slab)
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kmem_cache_destroy(sgp->slab);
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}
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kmem_cache_destroy(scsi_sdb_cache);
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return -ENOMEM;
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}
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void scsi_exit_queue(void)
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{
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int i;
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kmem_cache_destroy(scsi_sdb_cache);
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for (i = 0; i < SG_MEMPOOL_NR; i++) {
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struct sg_pool *sgp = sg_pools + i;
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mempool_destroy(sgp->pool);
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kmem_cache_destroy(sgp->slab);
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}
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}
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/**
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@ -285,6 +285,31 @@ size_t sg_pcopy_to_buffer(struct scatterlist *sgl, unsigned int nents,
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*/
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#define SG_MAX_SINGLE_ALLOC (PAGE_SIZE / sizeof(struct scatterlist))
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/*
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* The maximum number of SG segments that we will put inside a
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* scatterlist (unless chaining is used). Should ideally fit inside a
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* single page, to avoid a higher order allocation. We could define this
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* to SG_MAX_SINGLE_ALLOC to pack correctly at the highest order. The
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* minimum value is 32
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*/
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#define SG_CHUNK_SIZE 128
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/*
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* Like SG_CHUNK_SIZE, but for archs that have sg chaining. This limit
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* is totally arbitrary, a setting of 2048 will get you at least 8mb ios.
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*/
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#ifdef CONFIG_ARCH_HAS_SG_CHAIN
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#define SG_MAX_SEGMENTS 2048
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#else
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#define SG_MAX_SEGMENTS SG_CHUNK_SIZE
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#endif
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#ifdef CONFIG_SG_POOL
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void sg_free_table_chained(struct sg_table *table, bool first_chunk);
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int sg_alloc_table_chained(struct sg_table *table, int nents,
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struct scatterlist *first_chunk);
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#endif
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/*
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* sg page iterator
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*
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@ -17,25 +17,6 @@ enum scsi_timeouts {
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SCSI_DEFAULT_EH_TIMEOUT = 10 * HZ,
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};
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/*
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* The maximum number of SG segments that we will put inside a
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* scatterlist (unless chaining is used). Should ideally fit inside a
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* single page, to avoid a higher order allocation. We could define this
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* to SG_MAX_SINGLE_ALLOC to pack correctly at the highest order. The
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* minimum value is 32
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*/
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#define SG_CHUNK_SIZE 128
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/*
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* Like SG_CHUNK_SIZE, but for archs that have sg chaining. This limit
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* is totally arbitrary, a setting of 2048 will get you at least 8mb ios.
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*/
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#ifdef CONFIG_ARCH_HAS_SG_CHAIN
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#define SG_MAX_SEGMENTS 2048
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#else
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#define SG_MAX_SEGMENTS SG_CHUNK_SIZE
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#endif
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/*
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* DIX-capable adapters effectively support infinite chaining for the
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* protection information scatterlist
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@ -523,6 +523,13 @@ config SG_SPLIT
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a scatterlist. This should be selected by a driver or an API which
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whishes to split a scatterlist amongst multiple DMA channels.
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config SG_POOL
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def_bool n
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help
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Provides a helper to allocate chained scatterlists. This should be
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selected by a driver or an API which whishes to allocate chained
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scatterlist.
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#
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# sg chaining option
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#
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@ -178,6 +178,7 @@ obj-$(CONFIG_GENERIC_STRNLEN_USER) += strnlen_user.o
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obj-$(CONFIG_GENERIC_NET_UTILS) += net_utils.o
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obj-$(CONFIG_SG_SPLIT) += sg_split.o
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obj-$(CONFIG_SG_POOL) += sg_pool.o
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obj-$(CONFIG_STMP_DEVICE) += stmp_device.o
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obj-$(CONFIG_IRQ_POLL) += irq_poll.o
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172
lib/sg_pool.c
Normal file
172
lib/sg_pool.c
Normal file
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@ -0,0 +1,172 @@
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#include <linux/module.h>
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#include <linux/scatterlist.h>
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#include <linux/mempool.h>
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#include <linux/slab.h>
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#define SG_MEMPOOL_NR ARRAY_SIZE(sg_pools)
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#define SG_MEMPOOL_SIZE 2
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struct sg_pool {
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size_t size;
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char *name;
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struct kmem_cache *slab;
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mempool_t *pool;
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};
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#define SP(x) { .size = x, "sgpool-" __stringify(x) }
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#if (SG_CHUNK_SIZE < 32)
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#error SG_CHUNK_SIZE is too small (must be 32 or greater)
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#endif
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static struct sg_pool sg_pools[] = {
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SP(8),
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SP(16),
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#if (SG_CHUNK_SIZE > 32)
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SP(32),
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#if (SG_CHUNK_SIZE > 64)
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SP(64),
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#if (SG_CHUNK_SIZE > 128)
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SP(128),
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#if (SG_CHUNK_SIZE > 256)
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#error SG_CHUNK_SIZE is too large (256 MAX)
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#endif
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#endif
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#endif
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#endif
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SP(SG_CHUNK_SIZE)
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};
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#undef SP
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static inline unsigned int sg_pool_index(unsigned short nents)
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{
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unsigned int index;
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BUG_ON(nents > SG_CHUNK_SIZE);
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if (nents <= 8)
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index = 0;
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else
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index = get_count_order(nents) - 3;
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return index;
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}
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static void sg_pool_free(struct scatterlist *sgl, unsigned int nents)
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{
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struct sg_pool *sgp;
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sgp = sg_pools + sg_pool_index(nents);
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mempool_free(sgl, sgp->pool);
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}
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static struct scatterlist *sg_pool_alloc(unsigned int nents, gfp_t gfp_mask)
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{
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struct sg_pool *sgp;
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sgp = sg_pools + sg_pool_index(nents);
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return mempool_alloc(sgp->pool, gfp_mask);
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}
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/**
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* sg_free_table_chained - Free a previously mapped sg table
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* @table: The sg table header to use
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* @first_chunk: was first_chunk not NULL in sg_alloc_table_chained?
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*
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* Description:
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* Free an sg table previously allocated and setup with
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* sg_alloc_table_chained().
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*
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**/
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void sg_free_table_chained(struct sg_table *table, bool first_chunk)
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{
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if (first_chunk && table->orig_nents <= SG_CHUNK_SIZE)
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return;
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__sg_free_table(table, SG_CHUNK_SIZE, first_chunk, sg_pool_free);
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}
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EXPORT_SYMBOL_GPL(sg_free_table_chained);
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/**
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* sg_alloc_table_chained - Allocate and chain SGLs in an sg table
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* @table: The sg table header to use
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* @nents: Number of entries in sg list
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* @first_chunk: first SGL
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*
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* Description:
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* Allocate and chain SGLs in an sg table. If @nents@ is larger than
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* SG_CHUNK_SIZE a chained sg table will be setup.
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*
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**/
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int sg_alloc_table_chained(struct sg_table *table, int nents,
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struct scatterlist *first_chunk)
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{
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int ret;
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BUG_ON(!nents);
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if (first_chunk) {
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if (nents <= SG_CHUNK_SIZE) {
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table->nents = table->orig_nents = nents;
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sg_init_table(table->sgl, nents);
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return 0;
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}
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}
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ret = __sg_alloc_table(table, nents, SG_CHUNK_SIZE,
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first_chunk, GFP_ATOMIC, sg_pool_alloc);
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if (unlikely(ret))
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sg_free_table_chained(table, (bool)first_chunk);
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return ret;
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}
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EXPORT_SYMBOL_GPL(sg_alloc_table_chained);
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static __init int sg_pool_init(void)
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{
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int i;
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for (i = 0; i < SG_MEMPOOL_NR; i++) {
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struct sg_pool *sgp = sg_pools + i;
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int size = sgp->size * sizeof(struct scatterlist);
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sgp->slab = kmem_cache_create(sgp->name, size, 0,
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SLAB_HWCACHE_ALIGN, NULL);
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if (!sgp->slab) {
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printk(KERN_ERR "SG_POOL: can't init sg slab %s\n",
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sgp->name);
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goto cleanup_sdb;
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}
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sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
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sgp->slab);
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if (!sgp->pool) {
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printk(KERN_ERR "SG_POOL: can't init sg mempool %s\n",
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sgp->name);
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goto cleanup_sdb;
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}
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}
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return 0;
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cleanup_sdb:
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for (i = 0; i < SG_MEMPOOL_NR; i++) {
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struct sg_pool *sgp = sg_pools + i;
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if (sgp->pool)
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mempool_destroy(sgp->pool);
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if (sgp->slab)
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kmem_cache_destroy(sgp->slab);
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}
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return -ENOMEM;
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}
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static __exit void sg_pool_exit(void)
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{
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int i;
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for (i = 0; i < SG_MEMPOOL_NR; i++) {
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struct sg_pool *sgp = sg_pools + i;
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mempool_destroy(sgp->pool);
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kmem_cache_destroy(sgp->slab);
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}
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}
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module_init(sg_pool_init);
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module_exit(sg_pool_exit);
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