iscsi-target: Fix sess allocation leak in iscsi_login_zero_tsih_s1

This patch adds missing kfree() for an allocation in iscsi_login_zero_tsih_s1()
code, and make transport_init_session() check for IS_ERR() returns.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/iscsi/iscsi_target_login.c

@@ -224,7 +224,7 @@ static int iscsi_login_zero_tsih_s1(
 		iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
 				ISCSI_LOGIN_STATUS_NO_RESOURCES);
 		pr_err("Could not allocate memory for session\n");
-		return -1;
+		return -ENOMEM;
 	}
 
 	iscsi_login_set_conn_values(sess, conn, pdu->cid);
@@ -250,7 +250,8 @@ static int iscsi_login_zero_tsih_s1(
 		pr_err("idr_pre_get() for sess_idr failed\n");
 		iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
 				ISCSI_LOGIN_STATUS_NO_RESOURCES);
-		return -1;
+		kfree(sess);
+		return -ENOMEM;
 	}
 	spin_lock(&sess_idr_lock);
 	idr_get_new(&sess_idr, NULL, &sess->session_index);
@@ -270,14 +271,16 @@ static int iscsi_login_zero_tsih_s1(
 				ISCSI_LOGIN_STATUS_NO_RESOURCES);
 		pr_err("Unable to allocate memory for"
 				" struct iscsi_sess_ops.\n");
-		return -1;
+		kfree(sess);
+		return -ENOMEM;
 	}
 
 	sess->se_sess = transport_init_session();
-	if (!sess->se_sess) {
+	if (IS_ERR(sess->se_sess)) {
 		iscsit_tx_login_rsp(conn, ISCSI_STATUS_CLS_TARGET_ERR,
 				ISCSI_LOGIN_STATUS_NO_RESOURCES);
-		return -1;
+		kfree(sess);
+		return -ENOMEM;
 	}
 
 	return 0;