From patchwork Tue Nov 29 14:18:19 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Johan Hovold X-Patchwork-Id: 13058626 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 BA38DC46467 for ; Tue, 29 Nov 2022 14:20:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235427AbiK2OU5 (ORCPT ); Tue, 29 Nov 2022 09:20:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235383AbiK2OUl (ORCPT ); Tue, 29 Nov 2022 09:20:41 -0500 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4A7C268694; Tue, 29 Nov 2022 06:18:32 -0800 (PST) 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 dfw.source.kernel.org (Postfix) with ESMTPS id DB1E46176F; Tue, 29 Nov 2022 14:18:31 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 304C1C433C1; Tue, 29 Nov 2022 14:18:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1669731511; bh=ksilrIsLtIQNg+osJth3VSYezKbX/p5M2jGxv4Rz5jI=; h=From:To:Cc:Subject:Date:From; b=qtIhwVsxalVdPYtedK9PL8Z/2RUeeu1MHWuY51ZuO07+r9MJfE/xPnDTXCD+uwNTY vdh4fl9WRfdeLj0G47t5BIjwvzmV/lz8206QMFl6mriKYXf8H1hyCJS3SsGpaRTVEV P28suXZ1DoUMavy4TXzpSHsYKnW8eO9oNcogDO0eI7IUo/TytKzdY7RB9Wf6qXkxi+ psobVmV510vaDkOt60TKlkNYYoVu/uStMui1Mkl5vABgHO8Q8EU+8LmSje1+mOrqk3 4f9H53m045TlFIgxMSzpdX4ODNpdZqaH9Y6Gyzq+eGz4scM3L0rFeXA6MypRnNzG2l VdebTS6tG4IYA== Received: from johan by xi.lan with local (Exim 4.94.2) (envelope-from ) id 1p01RP-0003z9-RF; Tue, 29 Nov 2022 15:18:31 +0100 From: Johan Hovold To: Johan Hovold Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Ji-Ze Hong Subject: [PATCH] USB: serial: f81534: fix division by zero on line-speed change Date: Tue, 29 Nov 2022 15:18:19 +0100 Message-Id: <20221129141819.15310-1-johan@kernel.org> X-Mailer: git-send-email 2.37.4 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-usb@vger.kernel.org The driver leaves the line speed unchanged in case a requested speed is not supported. Make sure to handle the case where the current speed is B0 (hangup) without dividing by zero when determining the clock source. Fixes: 3aacac02f385 ("USB: serial: f81534: add high baud rate support") Cc: stable@vger.kernel.org # 4.16 Cc: Ji-Ze Hong (Peter Hong) Signed-off-by: Johan Hovold Reviewed-by: Greg Kroah-Hartman --- drivers/usb/serial/f81534.c | 12 +++++++----- 1 file changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/usb/serial/f81534.c b/drivers/usb/serial/f81534.c index ddfcd72eb0ae..4083ae961be4 100644 --- a/drivers/usb/serial/f81534.c +++ b/drivers/usb/serial/f81534.c @@ -536,9 +536,6 @@ static int f81534_submit_writer(struct usb_serial_port *port, gfp_t mem_flags) static u32 f81534_calc_baud_divisor(u32 baudrate, u32 clockrate) { - if (!baudrate) - return 0; - /* Round to nearest divisor */ return DIV_ROUND_CLOSEST(clockrate, baudrate); } @@ -568,9 +565,14 @@ static int f81534_set_port_config(struct usb_serial_port *port, u32 baud_list[] = {baudrate, old_baudrate, F81534_DEFAULT_BAUD_RATE}; for (i = 0; i < ARRAY_SIZE(baud_list); ++i) { - idx = f81534_find_clk(baud_list[i]); + baudrate = baud_list[i]; + if (baudrate == 0) { + tty_encode_baud_rate(tty, 0, 0); + return 0; + } + + idx = f81534_find_clk(baudrate); if (idx >= 0) { - baudrate = baud_list[i]; tty_encode_baud_rate(tty, baudrate, baudrate); break; }