tcm_loop: Send I_T_NEXUS_LOSS_OCCURRED UA

If the virtual SAS link is set to 'offline' we should be
queueing an I_T_NEXUS_LOSS_OCCURRED UA.

Signed-off-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
diff --git a/drivers/target/loopback/tcm_loop.c b/drivers/target/loopback/tcm_loop.c
index b179d93..5bc85ff 100644
--- a/drivers/target/loopback/tcm_loop.c
+++ b/drivers/target/loopback/tcm_loop.c
@@ -1034,6 +1034,11 @@
 	}
 	if (!strncmp(page, "offline", 7)) {
 		tl_tpg->tl_transport_status = TCM_TRANSPORT_OFFLINE;
+		if (tl_tpg->tl_nexus) {
+			struct se_session *tl_sess = tl_tpg->tl_nexus->se_sess;
+
+			core_allocate_nexus_loss_ua(tl_sess->se_node_acl);
+		}
 		return count;
 	}
 	return -EINVAL;
diff --git a/drivers/target/target_core_tpg.c b/drivers/target/target_core_tpg.c
index babde4a..2d0381d 100644
--- a/drivers/target/target_core_tpg.c
+++ b/drivers/target/target_core_tpg.c
@@ -41,6 +41,7 @@
 #include "target_core_internal.h"
 #include "target_core_alua.h"
 #include "target_core_pr.h"
+#include "target_core_ua.h"
 
 extern struct se_device *g_lun0_dev;
 
@@ -83,6 +84,22 @@
 }
 EXPORT_SYMBOL(core_tpg_get_initiator_node_acl);
 
+void core_allocate_nexus_loss_ua(
+	struct se_node_acl *nacl)
+{
+	struct se_dev_entry *deve;
+
+	if (!nacl)
+		return;
+
+	rcu_read_lock();
+	hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link)
+		core_scsi3_ua_allocate(deve, 0x29,
+			ASCQ_29H_NEXUS_LOSS_OCCURRED);
+	rcu_read_unlock();
+}
+EXPORT_SYMBOL(core_allocate_nexus_loss_ua);
+
 /*	core_tpg_add_node_to_devs():
  *
  *
diff --git a/include/target/target_core_fabric.h b/include/target/target_core_fabric.h
index 18afef9..69355fe 100644
--- a/include/target/target_core_fabric.h
+++ b/include/target/target_core_fabric.h
@@ -152,6 +152,7 @@
 void	transport_generic_request_failure(struct se_cmd *, sense_reason_t);
 void	__target_execute_cmd(struct se_cmd *);
 int	transport_lookup_tmr_lun(struct se_cmd *, u64);
+void	core_allocate_nexus_loss_ua(struct se_node_acl *acl);
 
 struct se_node_acl *core_tpg_get_initiator_node_acl(struct se_portal_group *tpg,
 		unsigned char *);