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

Nicholas A. Bellinger
2013-08-31T03:08:53Z

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>
---
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