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 X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id A63C3C433E0 for ; Wed, 30 Dec 2020 12:48:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 658392220B for ; Wed, 30 Dec 2020 12:48:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726791AbgL3Ms3 (ORCPT ); Wed, 30 Dec 2020 07:48:29 -0500 Received: from mail.kernel.org ([198.145.29.99]:50550 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726619AbgL3Ms2 (ORCPT ); Wed, 30 Dec 2020 07:48:28 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2837B2220B; Wed, 30 Dec 2020 12:47:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609332467; bh=+Vj4AXEbOGEO2HVS8Wk6KVWRPCQg4+wEXVUndvahp30=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=zA38ZEK6j8WGb/Pn/FdwSM/8Q1gZDhxVkijFp29XO3IPnW8XTyfGjXOI7e81eNzbZ 95MP0cZJ4qMet5iwrnwcUkj3QJhM6Bj4hSLPwORR6epoKvYNhONYV0Law4FxBTmyUG sIMdCBIdodFZKY5ZHyiIvnxxN/je4528+E0LfJl0= Date: Wed, 30 Dec 2020 13:49:14 +0100 From: Greg KH To: zhangqiumiao1@huawei.com Cc: jirislaby@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] tty: resolve loopback wait problem for aging serial port Message-ID: References: <1609331946-10165-1-git-send-email-zhangqiumiao1@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1609331946-10165-1-git-send-email-zhangqiumiao1@huawei.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 30, 2020 at 08:39:06PM +0800, zhangqiumiao1@huawei.com wrote: > From: Qiumiao Zhang > > Because serial port is low-speed device, serial port writing will be suspended > when the buffer of driver layer is full due to serial port aging. The concrete > representation is n_tty_write blocking in the process of wait_woken, the process > of writing serial port exists without feedback, and becomes a zombie process. > So for serial port, set the timeout value of wait_woken function to 60s. Wake up > and flush the buffer after timeout. > > Signed-off-by: Qiumiao Zhang > --- > drivers/tty/n_tty.c | 15 ++++++++++++++- > 1 file changed, 14 insertions(+), 1 deletion(-) What changed from v1? Always put that below the --- line as the documentation asks you to do so. Please fix up and submit a v3. thanks, greg k-h