target: Drop unnecessary core_tpg_register TFO parameter

This patch drops unnecessary target_core_fabric_ops parameter usage
for core_tpg_register() during fabric driver TFO->fabric_make_tpg()
se_portal_group creation callback execution.

Instead, use the existing se_wwn->wwn_tf->tf_ops pointer to ensure
fabric driver is really using the same TFO provided at module_init
time.

Also go ahead and drop the forward TFO declarations tree-wide, and
handling the special case for iscsi-target discovery TPG.

Cc: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

6 files changed, 35 insertions, 18 deletions

diff --git a/drivers/target/iscsi/iscsi_target_configfs.c b/drivers/target/iscsi/iscsi_target_configfs.c
index 523ae556e22c..c1898c84b3d2 100644
--- a/drivers/target/iscsi/iscsi_target_configfs.c
+++ b/drivers/target/iscsi/iscsi_target_configfs.c
@@ -1419,8 +1419,7 @@ static struct se_portal_group *lio_target_tiqn_addtpg(
 	if (!tpg)
 		return NULL;
 
-	ret = core_tpg_register(&iscsi_ops, wwn, &tpg->tpg_se_tpg,
-				SCSI_PROTOCOL_ISCSI);
+	ret = core_tpg_register(wwn, &tpg->tpg_se_tpg, SCSI_PROTOCOL_ISCSI);
 	if (ret < 0)
 		return NULL;
 
diff --git a/drivers/target/iscsi/iscsi_target_tpg.c b/drivers/target/iscsi/iscsi_target_tpg.c
index de8829102ab4..968068ffcb1c 100644
--- a/drivers/target/iscsi/iscsi_target_tpg.c
+++ b/drivers/target/iscsi/iscsi_target_tpg.c
@@ -66,8 +66,12 @@ int iscsit_load_discovery_tpg(void)
 		pr_err("Unable to allocate struct iscsi_portal_group\n");
 		return -1;
 	}
-
-	ret = core_tpg_register(&iscsi_ops, NULL, &tpg->tpg_se_tpg, -1);
+	/*
+	 * Save iscsi_ops pointer for special case discovery TPG that
+	 * doesn't exist as se_wwn->wwn_group within configfs.
+	 */
+	tpg->tpg_se_tpg.se_tpg_tfo = &iscsi_ops;
+	ret = core_tpg_register(NULL, &tpg->tpg_se_tpg, -1);
 	if (ret < 0) {
 		kfree(tpg);
 		return -1;
diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index b0c17614493e..bd9d11a6f823 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -40,8 +40,6 @@
 
 #define to_tcm_loop_hba(hba)	container_of(hba, struct tcm_loop_hba, dev)
 
-static const struct target_core_fabric_ops loop_ops;
-
 static struct workqueue_struct *tcm_loop_workqueue;
 static struct kmem_cache *tcm_loop_cmd_cache;
 
@@ -1081,8 +1079,7 @@ static struct se_portal_group *tcm_loop_make_naa_tpg(
 	/*
 	 * Register the tl_tpg as a emulated SAS TCM Target Endpoint
 	 */
-	ret = core_tpg_register(&loop_ops, wwn, &tl_tpg->tl_se_tpg,
-				tl_hba->tl_proto_id);
+	ret = core_tpg_register(wwn, &tl_tpg->tl_se_tpg, tl_hba->tl_proto_id);
 	if (ret < 0)
 		return ERR_PTR(-ENOMEM);
 
diff --git a/drivers/target/sbp/sbp_target.c b/drivers/target/sbp/sbp_target.c
index 28e3adf1eb85..42f82d32ca85 100644
--- a/drivers/target/sbp/sbp_target.c
+++ b/drivers/target/sbp/sbp_target.c
@@ -2055,7 +2055,7 @@ static struct se_portal_group *sbp_make_tpg(
 		goto out_free_tpg;
 	}
 
-	ret = core_tpg_register(&sbp_ops, wwn, &tpg->se_tpg, SCSI_PROTOCOL_SBP);
+	ret = core_tpg_register(wwn, &tpg->se_tpg, SCSI_PROTOCOL_SBP);
 	if (ret < 0)
 		goto out_unreg_mgt_agt;
 
diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index b9fcf2c4898e..2e77eebe1671 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -37,6 +37,7 @@
 
 #include <target/target_core_base.h>
 #include <target/target_core_backend.h>
+#include <target/target_core_configfs.h>
 #include <target/target_core_fabric.h>
 
 #include "target_core_internal.h"
@@ -487,16 +488,34 @@ static void core_tpg_lun_ref_release(struct percpu_ref *ref)
 }
 
 int core_tpg_register(
-	const struct target_core_fabric_ops *tfo,
 	struct se_wwn *se_wwn,
 	struct se_portal_group *se_tpg,
 	int proto_id)
 {
 	int ret;
 
+	if (!se_tpg)
+		return -EINVAL;
+	/*
+	 * For the typical case where core_tpg_register() is called by a
+	 * fabric driver from target_core_fabric_ops->fabric_make_tpg()
+	 * configfs context, use the original tf_ops pointer already saved
+	 * by target-core in target_fabric_make_wwn().
+	 *
+	 * Otherwise, for special cases like iscsi-target discovery TPGs
+	 * the caller is responsible for setting ->se_tpg_tfo ahead of
+	 * calling core_tpg_register().
+	 */
+	if (se_wwn)
+		se_tpg->se_tpg_tfo = se_wwn->wwn_tf->tf_ops;
+
+	if (!se_tpg->se_tpg_tfo) {
+		pr_err("Unable to locate se_tpg->se_tpg_tfo pointer\n");
+		return -EINVAL;
+	}
+
 	INIT_HLIST_HEAD(&se_tpg->tpg_lun_hlist);
 	se_tpg->proto_id = proto_id;
-	se_tpg->se_tpg_tfo = tfo;
 	se_tpg->se_tpg_wwn = se_wwn;
 	atomic_set(&se_tpg->tpg_pr_ref_count, 0);
 	INIT_LIST_HEAD(&se_tpg->acl_node_list);
@@ -524,9 +543,10 @@ int core_tpg_register(
 	spin_unlock_bh(&tpg_lock);
 
 	pr_debug("TARGET_CORE[%s]: Allocated portal_group for endpoint: %s, "
-		 "Proto: %d, Portal Tag: %u\n", tfo->get_fabric_name(),
-		tfo->tpg_get_wwn(se_tpg) ? tfo->tpg_get_wwn(se_tpg) : NULL,
-		se_tpg->proto_id, tfo->tpg_get_tag(se_tpg));
+		 "Proto: %d, Portal Tag: %u\n", se_tpg->se_tpg_tfo->get_fabric_name(),
+		se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) ?
+		se_tpg->se_tpg_tfo->tpg_get_wwn(se_tpg) : NULL,
+		se_tpg->proto_id, se_tpg->se_tpg_tfo->tpg_get_tag(se_tpg));
 
 	return 0;
 }
diff --git a/drivers/target/tcm_fc/tfc_conf.c b/drivers/target/tcm_fc/tfc_conf.c
index 8e1a54f2642c..80a4477fa7ee 100644
--- a/drivers/target/tcm_fc/tfc_conf.c
+++ b/drivers/target/tcm_fc/tfc_conf.c
@@ -47,8 +47,6 @@
 
 #include "tcm_fc.h"
 
-static const struct target_core_fabric_ops ft_fabric_ops;
-
 static LIST_HEAD(ft_wwn_list);
 DEFINE_MUTEX(ft_lport_lock);
 
@@ -282,8 +280,7 @@ static struct se_portal_group *ft_add_tpg(
 		return NULL;
 	}
 
-	ret = core_tpg_register(&ft_fabric_ops, wwn, &tpg->se_tpg,
-				SCSI_PROTOCOL_FCP);
+	ret = core_tpg_register(wwn, &tpg->se_tpg, SCSI_PROTOCOL_FCP);
 	if (ret < 0) {
 		destroy_workqueue(wq);
 		kfree(tpg);