From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B911AC43334 for ; Mon, 13 Jun 2022 12:11:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237969AbiFMMLz (ORCPT ); Mon, 13 Jun 2022 08:11:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54056 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1359354AbiFMMFo (ORCPT ); Mon, 13 Jun 2022 08:05:44 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A0B862B18E; Mon, 13 Jun 2022 04:00:00 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id D3082B80D3A; Mon, 13 Jun 2022 10:59:58 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3BC3FC3411C; Mon, 13 Jun 2022 10:59:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1655117997; bh=ZRMaL50SIMEkO456BZqAREZjkYPymIv0UKEaPWvWl6k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=SCX3pogYX0usIGppDFICuFkjqk81OWONS34b893uL6UoOFRqhP9soRH2YMkBE5b/I kDkIBinnV/rXqF23GG5PhQwPUmeasv2lX1nG9UDXybhL06AP6r9sTFpzyhA9deQ+ct rAPYso1aKc2XZQIzTviLmtM1ExhPvcX4QqGtsw+k= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ricardo Ribalda Delgado , =?UTF-8?q?Ilpo=20J=C3=A4rvinen?= , Sasha Levin Subject: [PATCH 4.19 206/287] serial: 8250_fintek: Check SER_RS485_RTS_* only with RS485 Date: Mon, 13 Jun 2022 12:10:30 +0200 Message-Id: <20220613094930.109269076@linuxfoundation.org> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220613094923.832156175@linuxfoundation.org> References: <20220613094923.832156175@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Ilpo Järvinen [ Upstream commit af0179270977508df6986b51242825d7edd59caf ] SER_RS485_RTS_ON_SEND and SER_RS485_RTS_AFTER_SEND relate to behavior within RS485 operation. The driver checks if they have the same value which is not possible to realize with the hardware. The check is taken regardless of SER_RS485_ENABLED flag and -EINVAL is returned when the check fails, which creates problems. This check makes it unnecessarily complicated to turn RS485 mode off as simple zeroed serial_rs485 struct will trigger that equal values check. In addition, the driver itself memsets its rs485 structure to zero when RS485 is disabled but if userspace would try to make an TIOCSRS485 ioctl() call with the very same struct, it would end up failing with -EINVAL which doesn't make much sense. Resolve the problem by moving the check inside SER_RS485_ENABLED block. Fixes: 7ecc77011c6f ("serial: 8250_fintek: Return -EINVAL on invalid configuration") Cc: Ricardo Ribalda Delgado Signed-off-by: Ilpo Järvinen Link: https://lore.kernel.org/r/035c738-8ea5-8b17-b1d7-84a7b3aeaa51@linux.intel.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin --- drivers/tty/serial/8250/8250_fintek.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/drivers/tty/serial/8250/8250_fintek.c b/drivers/tty/serial/8250/8250_fintek.c index 79a4958b3f5c..440023069f4f 100644 --- a/drivers/tty/serial/8250/8250_fintek.c +++ b/drivers/tty/serial/8250/8250_fintek.c @@ -197,12 +197,12 @@ static int fintek_8250_rs485_config(struct uart_port *port, if (!pdata) return -EINVAL; - /* Hardware do not support same RTS level on send and receive */ - if (!(rs485->flags & SER_RS485_RTS_ON_SEND) == - !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) - return -EINVAL; if (rs485->flags & SER_RS485_ENABLED) { + /* Hardware do not support same RTS level on send and receive */ + if (!(rs485->flags & SER_RS485_RTS_ON_SEND) == + !(rs485->flags & SER_RS485_RTS_AFTER_SEND)) + return -EINVAL; memset(rs485->padding, 0, sizeof(rs485->padding)); config |= RS485_URA; } else { -- 2.35.1