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>

1 files changed, 3 insertions, 0 deletions

diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index 7a16178424f9..d559c36692af 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 *,