[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 <hch@lst.de> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: James Bottomley <JBottomley@Parallels.com>
This commit is contained in:
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7c28334122
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89d9a56795
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@ -331,46 +331,103 @@ void scsi_put_command(struct scsi_cmnd *cmd)
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}
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}
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EXPORT_SYMBOL(scsi_put_command);
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EXPORT_SYMBOL(scsi_put_command);
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static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
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static struct scsi_host_cmd_pool *
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scsi_find_host_cmd_pool(struct Scsi_Host *shost)
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{
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{
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if (shost->hostt->cmd_size)
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return shost->hostt->cmd_pool;
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if (shost->unchecked_isa_dma)
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return &scsi_cmd_dma_pool;
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return &scsi_cmd_pool;
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}
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static void
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scsi_free_host_cmd_pool(struct scsi_host_cmd_pool *pool)
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{
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kfree(pool->sense_name);
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kfree(pool->cmd_name);
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kfree(pool);
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}
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static struct scsi_host_cmd_pool *
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scsi_alloc_host_cmd_pool(struct Scsi_Host *shost)
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{
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struct scsi_host_template *hostt = shost->hostt;
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struct scsi_host_cmd_pool *pool;
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pool = kzalloc(sizeof(*pool), GFP_KERNEL);
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if (!pool)
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return NULL;
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pool->cmd_name = kasprintf(GFP_KERNEL, "%s_cmd", hostt->name);
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pool->sense_name = kasprintf(GFP_KERNEL, "%s_sense", hostt->name);
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if (!pool->cmd_name || !pool->sense_name) {
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scsi_free_host_cmd_pool(pool);
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return NULL;
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}
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pool->slab_flags = SLAB_HWCACHE_ALIGN;
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if (shost->unchecked_isa_dma) {
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pool->slab_flags |= SLAB_CACHE_DMA;
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pool->gfp_mask = __GFP_DMA;
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}
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return pool;
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}
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static struct scsi_host_cmd_pool *
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scsi_get_host_cmd_pool(struct Scsi_Host *shost)
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{
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struct scsi_host_template *hostt = shost->hostt;
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struct scsi_host_cmd_pool *retval = NULL, *pool;
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struct scsi_host_cmd_pool *retval = NULL, *pool;
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size_t cmd_size = sizeof(struct scsi_cmnd) + hostt->cmd_size;
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/*
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/*
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* Select a command slab for this host and create it if not
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* Select a command slab for this host and create it if not
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* yet existent.
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* yet existent.
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*/
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*/
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mutex_lock(&host_cmd_pool_mutex);
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mutex_lock(&host_cmd_pool_mutex);
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pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
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pool = scsi_find_host_cmd_pool(shost);
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&scsi_cmd_pool;
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if (!pool) {
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pool = scsi_alloc_host_cmd_pool(shost);
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if (!pool)
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goto out;
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}
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if (!pool->users) {
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if (!pool->users) {
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pool->cmd_slab = kmem_cache_create(pool->cmd_name,
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pool->cmd_slab = kmem_cache_create(pool->cmd_name, cmd_size, 0,
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sizeof(struct scsi_cmnd), 0,
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pool->slab_flags, NULL);
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pool->slab_flags, NULL);
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if (!pool->cmd_slab)
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if (!pool->cmd_slab)
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goto fail;
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goto out_free_pool;
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pool->sense_slab = kmem_cache_create(pool->sense_name,
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pool->sense_slab = kmem_cache_create(pool->sense_name,
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SCSI_SENSE_BUFFERSIZE, 0,
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SCSI_SENSE_BUFFERSIZE, 0,
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pool->slab_flags, NULL);
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pool->slab_flags, NULL);
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if (!pool->sense_slab) {
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if (!pool->sense_slab)
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kmem_cache_destroy(pool->cmd_slab);
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goto out_free_slab;
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goto fail;
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}
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}
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}
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pool->users++;
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pool->users++;
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retval = pool;
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retval = pool;
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fail:
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out:
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mutex_unlock(&host_cmd_pool_mutex);
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mutex_unlock(&host_cmd_pool_mutex);
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return retval;
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return retval;
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out_free_slab:
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kmem_cache_destroy(pool->cmd_slab);
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out_free_pool:
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if (hostt->cmd_size)
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scsi_free_host_cmd_pool(pool);
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goto out;
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}
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}
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static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
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static void scsi_put_host_cmd_pool(struct Scsi_Host *shost)
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{
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{
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struct scsi_host_template *hostt = shost->hostt;
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struct scsi_host_cmd_pool *pool;
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struct scsi_host_cmd_pool *pool;
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mutex_lock(&host_cmd_pool_mutex);
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mutex_lock(&host_cmd_pool_mutex);
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pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
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pool = scsi_find_host_cmd_pool(shost);
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&scsi_cmd_pool;
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/*
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/*
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* This may happen if a driver has a mismatched get and put
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* This may happen if a driver has a mismatched get and put
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* of the command pool; the driver should be implicated in
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* of the command pool; the driver should be implicated in
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@ -381,6 +438,8 @@ static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
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if (!--pool->users) {
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if (!--pool->users) {
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kmem_cache_destroy(pool->cmd_slab);
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kmem_cache_destroy(pool->cmd_slab);
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kmem_cache_destroy(pool->sense_slab);
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kmem_cache_destroy(pool->sense_slab);
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if (hostt->cmd_size)
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scsi_free_host_cmd_pool(pool);
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}
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}
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mutex_unlock(&host_cmd_pool_mutex);
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mutex_unlock(&host_cmd_pool_mutex);
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}
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}
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@ -397,14 +456,13 @@ static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
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*/
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*/
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int scsi_setup_command_freelist(struct Scsi_Host *shost)
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int scsi_setup_command_freelist(struct Scsi_Host *shost)
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{
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{
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struct scsi_cmnd *cmd;
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const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
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const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
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struct scsi_cmnd *cmd;
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spin_lock_init(&shost->free_list_lock);
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spin_lock_init(&shost->free_list_lock);
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INIT_LIST_HEAD(&shost->free_list);
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INIT_LIST_HEAD(&shost->free_list);
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shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
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shost->cmd_pool = scsi_get_host_cmd_pool(shost);
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if (!shost->cmd_pool)
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if (!shost->cmd_pool)
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return -ENOMEM;
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return -ENOMEM;
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@ -413,7 +471,7 @@ int scsi_setup_command_freelist(struct Scsi_Host *shost)
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*/
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*/
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cmd = scsi_host_alloc_command(shost, gfp_mask);
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cmd = scsi_host_alloc_command(shost, gfp_mask);
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if (!cmd) {
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if (!cmd) {
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scsi_put_host_cmd_pool(gfp_mask);
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scsi_put_host_cmd_pool(shost);
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shost->cmd_pool = NULL;
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shost->cmd_pool = NULL;
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return -ENOMEM;
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return -ENOMEM;
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}
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}
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@ -442,7 +500,7 @@ void scsi_destroy_command_freelist(struct Scsi_Host *shost)
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scsi_host_free_command(shost, cmd);
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scsi_host_free_command(shost, cmd);
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}
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}
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shost->cmd_pool = NULL;
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shost->cmd_pool = NULL;
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scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
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scsi_put_host_cmd_pool(shost);
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}
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}
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#ifdef CONFIG_SCSI_LOGGING
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#ifdef CONFIG_SCSI_LOGGING
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@ -15,6 +15,7 @@ struct completion;
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struct module;
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struct module;
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struct scsi_cmnd;
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struct scsi_cmnd;
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struct scsi_device;
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struct scsi_device;
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struct scsi_host_cmd_pool;
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struct scsi_target;
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struct scsi_target;
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struct Scsi_Host;
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struct Scsi_Host;
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struct scsi_host_cmd_pool;
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struct scsi_host_cmd_pool;
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@ -524,6 +525,12 @@ struct scsi_host_template {
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* scsi_netlink.h
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* scsi_netlink.h
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*/
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*/
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u64 vendor_id;
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u64 vendor_id;
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/*
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* Additional per-command data allocated for the driver.
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*/
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unsigned int cmd_size;
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struct scsi_host_cmd_pool *cmd_pool;
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};
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};
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/*
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/*
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