iscsi-target: Add explicit set of cache_dynamic_acls=1 for TPG demo-mode

We've had reports in the past about this specific case, so it's time to
go ahead and explicitly set cache_dynamic_acls=1 for generate_node_acls=1
(TPG demo-mode) operation.

During normal generate_node_acls=0 operation with explicit NodeACLs ->
se_node_acl memory is persistent to the configfs group located at
/sys/kernel/config/target/$TARGETNAME/$TPGT/acls/$INITIATORNAME, so in
the generate_node_acls=1 case we want the reservation logic to reference
existing per initiator IQN se_node_acl memory (not to generate a new
se_node_acl), so go ahead and always set cache_dynamic_acls=1 when
TPG demo-mode is enabled.

Reported-by: Ronnie Sahlberg <ronniesahlberg@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/iscsi_target_tpg.c

@@ -677,6 +677,12 @@ int iscsit_ta_generate_node_acls(
 	pr_debug("iSCSI_TPG[%hu] - Generate Initiator Portal Group ACLs: %s\n",
 		tpg->tpgt, (a->generate_node_acls) ? "Enabled" : "Disabled");
 
+	if (flag == 1 && a->cache_dynamic_acls == 0) {
+		pr_debug("Explicitly setting cache_dynamic_acls=1 when "
+			"generate_node_acls=1\n");
+		a->cache_dynamic_acls = 1;
+	}
+
 	return 0;
 }
 
@@ -716,6 +722,12 @@ int iscsit_ta_cache_dynamic_acls(
 		return -EINVAL;
 	}
 
+	if (a->generate_node_acls == 1 && flag == 0) {
+		pr_debug("Skipping cache_dynamic_acls=0 when"
+			" generate_node_acls=1\n");
+		return 0;
+	}
+
 	a->cache_dynamic_acls = flag;
 	pr_debug("iSCSI_TPG[%hu] - Cache Dynamic Initiator Portal Group"
 		" ACLs %s\n", tpg->tpgt, (a->cache_dynamic_acls) ?