lib/iscsi: Exit related connections at the start of target node destruction

When any iSCSI target is destructed, if the target exits all corresponding
connections first, destructing SCSI device will be easier.

Hence, iscsi_tgt_node_destruct() starts exiting all corresponding
connections. Then it destructs SCSI device immediately if no active
active connections, or waits for the completion if there is any
active connection for the target.

Change-Id: Ibd4a29789faecfefccefa1153a519c43d040a00d
Signed-off-by: Shuhei Matsumoto <shuhei.matsumoto.xt@hitachi.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/450737
Tested-by: SPDK CI Jenkins <sys_sgci@intel.com>
Reviewed-by: Jim Harris <james.r.harris@intel.com>
Reviewed-by: Changpeng Liu <changpeng.liu@intel.com>

lib/iscsi/tgt_node.c

@@ -624,6 +624,37 @@ iscsi_tgt_node_delete_all_pg_maps(struct spdk_iscsi_tgt_node *target)
 	}
 }
 
+static void
+_iscsi_tgt_node_destruct(struct spdk_iscsi_tgt_node *target)
+{
+	free(target->name);
+	free(target->alias);
+
+	pthread_mutex_lock(&g_spdk_iscsi.mutex);
+	iscsi_tgt_node_delete_all_pg_maps(target);
+	pthread_mutex_unlock(&g_spdk_iscsi.mutex);
+
+	pthread_mutex_destroy(&target->mutex);
+	free(target);
+}
+
+static int
+iscsi_tgt_node_check_active_conns(void *arg)
+{
+	struct spdk_iscsi_tgt_node *target = arg;
+
+	if (spdk_iscsi_get_active_conns(target) != 0) {
+		return 1;
+	}
+
+	spdk_poller_unregister(&target->destruct_poller);
+
+	spdk_scsi_dev_destruct(target->dev);
+	_iscsi_tgt_node_destruct(target);
+
+	return 1;
+}
+
 static void
 iscsi_tgt_node_destruct(struct spdk_iscsi_tgt_node *target)
 {
@@ -638,17 +669,16 @@ iscsi_tgt_node_destruct(struct spdk_iscsi_tgt_node *target)
 
 	target->destructed = true;
 
-	spdk_scsi_dev_destruct(target->dev);
+	spdk_iscsi_conns_start_exit(target);
 
-	free(target->name);
-	free(target->alias);
+	if (spdk_iscsi_get_active_conns(target) != 0) {
+		target->destruct_poller = spdk_poller_register(iscsi_tgt_node_check_active_conns,
+					  target, 10);
+	} else {
+		spdk_scsi_dev_destruct(target->dev);
+		_iscsi_tgt_node_destruct(target);
+	}
 
-	pthread_mutex_lock(&g_spdk_iscsi.mutex);
-	iscsi_tgt_node_delete_all_pg_maps(target);
-	pthread_mutex_unlock(&g_spdk_iscsi.mutex);
-
-	pthread_mutex_destroy(&target->mutex);
-	free(target);
 }
 
 static int

lib/iscsi/tgt_node.h

@@ -88,6 +88,7 @@ struct spdk_iscsi_tgt_node {
 	TAILQ_ENTRY(spdk_iscsi_tgt_node) tailq;
 
 	bool destructed;
+	struct spdk_poller *destruct_poller;
 };
 
 int spdk_iscsi_parse_tgt_nodes(void);

test/unit/lib/iscsi/tgt_node.c/tgt_node_ut.c

@@ -42,6 +42,7 @@
 #include "iscsi/tgt_node.c"
 #include "scsi/scsi_internal.h"
 #include "unit/lib/json_mock.c"
+#include "common/lib/test_env.c"
 
 struct spdk_iscsi_globals g_spdk_iscsi;