Re: [PATCH-v5 2/6] target: Add transport_init_session_tags using per-cpu ida

[Asias He <asias@redhat.com>]

On Sat, Aug 31, 2013 at 02:52:32AM +0000, Nicholas A. Bellinger wrote:
> From: Nicholas Bellinger <nab@linux-iscsi.org>
> 
> This patch adds lib/idr.c based transport_init_session_tags() logic
> that allows fabric drivers to setup a per-cpu se_sess->sess_tag_pool
> and associated se_sess->sess_cmd_map for basic tagged pre-allocation
> of fabric descriptor sized memory.
> 
> v5 changes:
>   - Convert to percpu_ida.h include
> 
> v4 changes:
>   - Add transport_alloc_session_tags() for fabrics that need early
>     transport_init_session()
> 
> v3 changes:
>   - Update to percpu-ida usage
> 
> Cc: Kent Overstreet <kmo@daterainc.com>
> Cc: Asias He <asias@redhat.com>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Reviewed-by: Asias He <asias@redhat.com>

> ---
>  drivers/target/target_core_transport.c |   48 ++++++++++++++++++++++++++++++++
>  include/target/target_core_base.h      |    5 +++
>  include/target/target_core_fabric.h    |    3 ++
>  3 files changed, 56 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
> index 7172d00..98ec711 100644
> --- a/drivers/target/target_core_transport.c
> +++ b/drivers/target/target_core_transport.c
> @@ -232,6 +232,50 @@ struct se_session *transport_init_session(void)
>  }
>  EXPORT_SYMBOL(transport_init_session);
>  
> +int transport_alloc_session_tags(struct se_session *se_sess,
> +			         unsigned int tag_num, unsigned int tag_size)
> +{
> +	int rc;
> +
> +	se_sess->sess_cmd_map = kzalloc(tag_num * tag_size, GFP_KERNEL);
> +	if (!se_sess->sess_cmd_map) {
> +		pr_err("Unable to allocate se_sess->sess_cmd_map\n");
> +		return -ENOMEM;
> +	}
> +
> +	rc = percpu_ida_init(&se_sess->sess_tag_pool, tag_num);
> +	if (rc < 0) {
> +		pr_err("Unable to init se_sess->sess_tag_pool,"
> +			" tag_num: %u\n", tag_num);
> +		kfree(se_sess->sess_cmd_map);
> +		se_sess->sess_cmd_map = NULL;
> +		return -ENOMEM;
> +	}
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL(transport_alloc_session_tags);
> +
> +struct se_session *transport_init_session_tags(unsigned int tag_num,
> +					       unsigned int tag_size)
> +{
> +	struct se_session *se_sess;
> +	int rc;
> +
> +	se_sess = transport_init_session();
> +	if (IS_ERR(se_sess))
> +		return se_sess;
> +
> +	rc = transport_alloc_session_tags(se_sess, tag_num, tag_size);
> +	if (rc < 0) {
> +		transport_free_session(se_sess);
> +		return ERR_PTR(-ENOMEM);
> +	}
> +
> +	return se_sess;
> +}
> +EXPORT_SYMBOL(transport_init_session_tags);
> +
>  /*
>   * Called with spin_lock_irqsave(&struct se_portal_group->session_lock called.
>   */
> @@ -367,6 +411,10 @@ EXPORT_SYMBOL(transport_deregister_session_configfs);
>  
>  void transport_free_session(struct se_session *se_sess)
>  {
> +	if (se_sess->sess_cmd_map) {
> +		percpu_ida_destroy(&se_sess->sess_tag_pool);
> +		kfree(se_sess->sess_cmd_map);
> +	}
>  	kmem_cache_free(se_sess_cache, se_sess);
>  }
>  EXPORT_SYMBOL(transport_free_session);
> diff --git a/include/target/target_core_base.h b/include/target/target_core_base.h
> index e34fc90..bd55acd 100644
> --- a/include/target/target_core_base.h
> +++ b/include/target/target_core_base.h
> @@ -5,6 +5,7 @@
>  #include <linux/configfs.h>
>  #include <linux/dma-mapping.h>
>  #include <linux/blkdev.h>
> +#include <linux/percpu_ida.h>
>  #include <scsi/scsi_cmnd.h>
>  #include <net/sock.h>
>  #include <net/tcp.h>
> @@ -415,6 +416,8 @@ struct se_cmd {
>  	enum dma_data_direction	data_direction;
>  	/* For SAM Task Attribute */
>  	int			sam_task_attr;
> +	/* Used for se_sess->sess_tag_pool */
> +	unsigned int		map_tag;
>  	/* Transport protocol dependent state, see transport_state_table */
>  	enum transport_state_table t_state;
>  	unsigned		cmd_wait_set:1;
> @@ -536,6 +539,8 @@ struct se_session {
>  	struct list_head	sess_wait_list;
>  	spinlock_t		sess_cmd_lock;
>  	struct kref		sess_kref;
> +	void			*sess_cmd_map;
> +	struct percpu_ida	sess_tag_pool;
>  };
>  
>  struct se_device;
> diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
> index 7a16178..d559c36 100644
> --- a/include/target/target_core_fabric.h
> +++ b/include/target/target_core_fabric.h
> @@ -84,6 +84,9 @@ struct target_core_fabric_ops {
>  };
>  
>  struct se_session *transport_init_session(void);
> +int transport_alloc_session_tags(struct se_session *, unsigned int,
> +		unsigned int);
> +struct se_session *transport_init_session_tags(unsigned int, unsigned int);
>  void	__transport_register_session(struct se_portal_group *,
>  		struct se_node_acl *, struct se_session *, void *);
>  void	transport_register_session(struct se_portal_group *,
> -- 
> 1.7.2.5
> 

-- 
Asias