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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 243D3C433E0 for ; Thu, 21 May 2020 02:09:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F3002206D4 for ; Thu, 21 May 2020 02:09:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727882AbgEUCJc (ORCPT ); Wed, 20 May 2020 22:09:32 -0400 Received: from smtprelay0134.hostedemail.com ([216.40.44.134]:38168 "EHLO smtprelay.hostedemail.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726840AbgEUCJb (ORCPT ); Wed, 20 May 2020 22:09:31 -0400 Received: from filter.hostedemail.com (clb03-v110.bra.tucows.net [216.40.38.60]) by smtprelay05.hostedemail.com (Postfix) with ESMTP id 9A46C1802E8BC; Thu, 21 May 2020 02:09:30 +0000 (UTC) X-Session-Marker: 6A6F6540706572636865732E636F6D X-HE-Tag: ducks22_401036126d1a X-Filterd-Recvd-Size: 2806 Received: from XPS-9350.home (unknown [47.151.136.130]) (Authenticated sender: joe@perches.com) by omf05.hostedemail.com (Postfix) with ESMTPA; Thu, 21 May 2020 02:09:29 +0000 (UTC) Message-ID: <032f1e9eec231e230781931ca8525ab2d29ae206.camel@perches.com> Subject: Re: [RFC PATCH 2/2] init: Allow multi-line output of kernel command line From: Joe Perches To: Andrew Morton Cc: Sergey Senozhatsky , Chenggang Wang , linux-kernel@vger.kernel.org, Petr Mladek , Steven Rostedt Date: Wed, 20 May 2020 19:09:27 -0700 In-Reply-To: <20200520180028.8fc1b7890774c6f92a6c2623@linux-foundation.org> References: <2b3832fed9370f0f8dfd1ea33dddb1d05a36e265.1589916689.git.joe@perches.com> <20200520044127.GB938@jagdpanzerIV.localdomain> <20200520121000.GF520@jagdpanzerIV.localdomain> <19a8c717f8d9dc76f2b09e6dd19f3fbb71bf29c5.camel@perches.com> <20200520180028.8fc1b7890774c6f92a6c2623@linux-foundation.org> Content-Type: text/plain; charset="ISO-8859-1" User-Agent: Evolution 3.36.1-2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2020-05-20 at 18:00 -0700, Andrew Morton wrote: > On Wed, 20 May 2020 13:36:45 -0700 Joe Perches wrote: > > > On Wed, 2020-05-20 at 21:10 +0900, Sergey Senozhatsky wrote: > > > On (20/05/19 21:58), Joe Perches wrote: > > > [..] > > > > > Maybe we can > > > > > use here something rather random and much shorter instead. E.g. > > > > > 256 chars. Hmm. How > > > > > > > > min(some_max like 132/256, PRINTK_LOG_LINE_MAX) > > > > > > > > would work. > > > > > > An alternative approach would be to do what we do in the > > > print_modules() (the list of modules which can definitely > > > be longer than 1K chars). > > > > > > We can split command line in a loop - memchr(pos, ' ') - and > > > pr_cont() parts of the command line. pr_cont() has overflow > > > control and it flushes cont buffer before it overflows, so > > > we should not lose anything. > > > > It doesn't matter much here, but I believe > > there's an 8k max buffer for pr_cont output. > > > > include/linux/printk.h:#define CONSOLE_EXT_LOG_MAX 8192 > > > > Anyway, no worries, it simplifies the loop if > > done that way. > > I'm wondering if we shold add a kernel puts() (putsk()? yuk) which can > puts() a string of any length. > > I'm counting around 150 instances of printk("%s", ...) and pr_foo("%s", > ...) which could perhaps be converted, thus saving an argument. I'd expect that it hardly matters. printk(KERN_CONT "string") works.