target: Fix se_tpg_tfo->tf_subsys regression + remove tf_subsystem

There is just one configfs subsystem in the target code, so we might as
well add two helpers to reference / unreference it from the core code
instead of passing pointers to it around.

This fixes a regression introduced for v4.1-rc1 with commit 9ac8928e6,
where configfs_depend_item() callers using se_tpg_tfo->tf_subsys would
fail, because the assignment from the original target_core_subsystem[]
is no longer happening at target_register_template() time.

(Fix target_core_exit_configfs pointer dereference - Sagi)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reported-by: Himanshu Madhani <himanshu.madhani@qlogic.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index 17c7f5ac7ea0..0f4dc3768587 100644
--- a/include/target/target_core_fabric.h
+++ b/include/target/target_core_fabric.h
@@ -4,7 +4,6 @@
 struct target_core_fabric_ops {
 	struct module *module;
 	const char *name;
-	struct configfs_subsystem *tf_subsys;
 	char *(*get_fabric_name)(void);
 	u8 (*get_fabric_proto_ident)(struct se_portal_group *);
 	char *(*tpg_get_wwn)(struct se_portal_group *);
@@ -109,6 +108,9 @@ struct target_core_fabric_ops {
 int target_register_template(const struct target_core_fabric_ops *fo);
 void target_unregister_template(const struct target_core_fabric_ops *fo);
 
+int target_depend_item(struct config_item *item);
+void target_undepend_item(struct config_item *item);
+
 struct se_session *transport_init_session(enum target_prot_op);
 int transport_alloc_session_tags(struct se_session *, unsigned int,
 		unsigned int);