From 89d9a567952baec13e26ada3e438f1b642d66b6e Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 20 Feb 2014 14:21:01 -0800 Subject: [PATCH] [SCSI] add support for per-host cmd pools This allows drivers to specify the size of their per-command private data in the host template and then get extra memory allocated for each command instead of needing another allocation in ->queuecommand. With the current SCSI code that already does multiple allocations for each command this probably doesn't make a big performance impact, but it allows to clean up the drivers, and prepare them for using the blk-mq infrastructure where the common allocation will make a difference. Signed-off-by: Christoph Hellwig Reviewed-by: Paolo Bonzini Signed-off-by: James Bottomley --- drivers/scsi/scsi.c | 96 ++++++++++++++++++++++++++++++++-------- include/scsi/scsi_host.h | 7 +++ 2 files changed, 84 insertions(+), 19 deletions(-) diff --git a/drivers/scsi/scsi.c b/drivers/scsi/scsi.c index 586c241c941e..c4d632c27a3e 100644 --- a/drivers/scsi/scsi.c +++ b/drivers/scsi/scsi.c @@ -331,46 +331,103 @@ void scsi_put_command(struct scsi_cmnd *cmd) } EXPORT_SYMBOL(scsi_put_command); -static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask) +static struct scsi_host_cmd_pool * +scsi_find_host_cmd_pool(struct Scsi_Host *shost) { + if (shost->hostt->cmd_size) + return shost->hostt->cmd_pool; + if (shost->unchecked_isa_dma) + return &scsi_cmd_dma_pool; + return &scsi_cmd_pool; +} + +static void +scsi_free_host_cmd_pool(struct scsi_host_cmd_pool *pool) +{ + kfree(pool->sense_name); + kfree(pool->cmd_name); + kfree(pool); +} + +static struct scsi_host_cmd_pool * +scsi_alloc_host_cmd_pool(struct Scsi_Host *shost) +{ + struct scsi_host_template *hostt = shost->hostt; + struct scsi_host_cmd_pool *pool; + + pool = kzalloc(sizeof(*pool), GFP_KERNEL); + if (!pool) + return NULL; + + pool->cmd_name = kasprintf(GFP_KERNEL, "%s_cmd", hostt->name); + pool->sense_name = kasprintf(GFP_KERNEL, "%s_sense", hostt->name); + if (!pool->cmd_name || !pool->sense_name) { + scsi_free_host_cmd_pool(pool); + return NULL; + } + + pool->slab_flags = SLAB_HWCACHE_ALIGN; + if (shost->unchecked_isa_dma) { + pool->slab_flags |= SLAB_CACHE_DMA; + pool->gfp_mask = __GFP_DMA; + } + return pool; +} + +static struct scsi_host_cmd_pool * +scsi_get_host_cmd_pool(struct Scsi_Host *shost) +{ + struct scsi_host_template *hostt = shost->hostt; struct scsi_host_cmd_pool *retval = NULL, *pool; + size_t cmd_size = sizeof(struct scsi_cmnd) + hostt->cmd_size; + /* * Select a command slab for this host and create it if not * yet existent. */ mutex_lock(&host_cmd_pool_mutex); - pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool : - &scsi_cmd_pool; + pool = scsi_find_host_cmd_pool(shost); + if (!pool) { + pool = scsi_alloc_host_cmd_pool(shost); + if (!pool) + goto out; + } + if (!pool->users) { - pool->cmd_slab = kmem_cache_create(pool->cmd_name, - sizeof(struct scsi_cmnd), 0, + pool->cmd_slab = kmem_cache_create(pool->cmd_name, cmd_size, 0, pool->slab_flags, NULL); if (!pool->cmd_slab) - goto fail; + goto out_free_pool; pool->sense_slab = kmem_cache_create(pool->sense_name, SCSI_SENSE_BUFFERSIZE, 0, pool->slab_flags, NULL); - if (!pool->sense_slab) { - kmem_cache_destroy(pool->cmd_slab); - goto fail; - } + if (!pool->sense_slab) + goto out_free_slab; } pool->users++; retval = pool; - fail: +out: mutex_unlock(&host_cmd_pool_mutex); return retval; + +out_free_slab: + kmem_cache_destroy(pool->cmd_slab); +out_free_pool: + if (hostt->cmd_size) + scsi_free_host_cmd_pool(pool); + goto out; } -static void scsi_put_host_cmd_pool(gfp_t gfp_mask) +static void scsi_put_host_cmd_pool(struct Scsi_Host *shost) { + struct scsi_host_template *hostt = shost->hostt; struct scsi_host_cmd_pool *pool; mutex_lock(&host_cmd_pool_mutex); - pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool : - &scsi_cmd_pool; + pool = scsi_find_host_cmd_pool(shost); + /* * This may happen if a driver has a mismatched get and put * of the command pool; the driver should be implicated in @@ -381,6 +438,8 @@ static void scsi_put_host_cmd_pool(gfp_t gfp_mask) if (!--pool->users) { kmem_cache_destroy(pool->cmd_slab); kmem_cache_destroy(pool->sense_slab); + if (hostt->cmd_size) + scsi_free_host_cmd_pool(pool); } mutex_unlock(&host_cmd_pool_mutex); } @@ -397,14 +456,13 @@ static void scsi_put_host_cmd_pool(gfp_t gfp_mask) */ int scsi_setup_command_freelist(struct Scsi_Host *shost) { - struct scsi_cmnd *cmd; const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL; + struct scsi_cmnd *cmd; spin_lock_init(&shost->free_list_lock); INIT_LIST_HEAD(&shost->free_list); - shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask); - + shost->cmd_pool = scsi_get_host_cmd_pool(shost); if (!shost->cmd_pool) return -ENOMEM; @@ -413,7 +471,7 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost) */ cmd = scsi_host_alloc_command(shost, gfp_mask); if (!cmd) { - scsi_put_host_cmd_pool(gfp_mask); + scsi_put_host_cmd_pool(shost); shost->cmd_pool = NULL; return -ENOMEM; } @@ -442,7 +500,7 @@ void scsi_destroy_command_freelist(struct Scsi_Host *shost) scsi_host_free_command(shost, cmd); } shost->cmd_pool = NULL; - scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL); + scsi_put_host_cmd_pool(shost); } #ifdef CONFIG_SCSI_LOGGING diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 53075e5039e6..94844fc77b97 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -15,6 +15,7 @@ struct completion; struct module; struct scsi_cmnd; struct scsi_device; +struct scsi_host_cmd_pool; struct scsi_target; struct Scsi_Host; struct scsi_host_cmd_pool; @@ -524,6 +525,12 @@ struct scsi_host_template { * scsi_netlink.h */ u64 vendor_id; + + /* + * Additional per-command data allocated for the driver. + */ + unsigned int cmd_size; + struct scsi_host_cmd_pool *cmd_pool; }; /* -- 2.20.1