target: Add transport_init_session_tags using per-cpu ida

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>
Reviewed-by: Asias He <asias@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

diff --git a/drivers/target/target_core_transport.c b/drivers/target/target_core_transport.c
index 7172d005d063439999ddaa619ef0a96877b42cec..98ec7110873b1eff31de260d287ad9854cc606d9 100644 (file)
--- 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 e34fc904f2e153f8bd6e1c3162fa914ca0bfb189..bd55acd430056fbb6c48c8f460806faa46b960ef 100644 (file)
--- 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 7a16178424f9af3e9ac57eceb1629eda100fb0b9..d559c36692afab023fe197fbbe513023e3f58477 100644 (file)
--- 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 *,