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=-0.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 32CD4C433DF for ; Thu, 21 May 2020 12:49:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F24DE2070A for ; Thu, 21 May 2020 12:49:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="nRekUtaW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729296AbgEUMtB (ORCPT ); Thu, 21 May 2020 08:49:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39116 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729077AbgEUMtA (ORCPT ); Thu, 21 May 2020 08:49:00 -0400 Received: from mail-pj1-x1044.google.com (mail-pj1-x1044.google.com [IPv6:2607:f8b0:4864:20::1044]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A0B08C061A0E for ; Thu, 21 May 2020 05:49:00 -0700 (PDT) Received: by mail-pj1-x1044.google.com with SMTP id q9so2981464pjm.2 for ; Thu, 21 May 2020 05:49:00 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=ThicM2MINEcLmZzXQZhlZBSaO4KVfv3Uo4/fCOM5QbM=; b=nRekUtaW1++FK1DM8dhcPPdCGdgFZMRJQshCPLZ1SbxcqEzPFkK6IIaRe6CHJuhj0V c3X9OdUqHHn9T75yReCLaYm2z/NY9bmNplKLhDj5YQxXw851VQZULFxU1DbJQW365BSH s0xzs6LKpqORMynObYwnRUNbXcbmImuw3AWgooyozs1Agne5cMm6WTUzN8iW7FnJBPOk VHlzl2WAQZ2X1ebO3BJ2YzrSS0ulaov9j/c64miMmH3HwdrGdP+1VKP0oR2rHwJ4Qyev ZhtVaN3gCebGT10uiXLE3yp/LBv6jdLbHcItA5MTAmnKSRC3sb7MHTt3bvKB3IkA3i8k pMbQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:date:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=ThicM2MINEcLmZzXQZhlZBSaO4KVfv3Uo4/fCOM5QbM=; b=f/BEcuEtCBHUo5DrnJ6bcuJStAnl2xBaDMOGecqTCjRFlxO5ToLWy7e8fPzd2sQYVN hR56jI+ZofYHlTdHpBdv2YBJ/7ULhA6JVzcokip7sMIAEKwDxYSjv7UuK45EOXZ3ynpN jL3p0XOauRWDZuAo1GsWHl3G8fsKh2NkpiFi1SsoWQIb6MQAlXfTZJ+asuDKcSRL7L6g jiGmdkltEd4k3zDAViygFxMqcP7d4rd6/vvDWqaeHabWftDIi2z6+0Y6taMSt3Ai7mpV N6DNWBV6/gstyn+PN0RXZCa9FtJLOCY0FNXBkp95EpedS/SYKlKRpundPp05HfDjQCXf DMjg== X-Gm-Message-State: AOAM5307wwnANZYCf5V6bYH2a+x7q9II+ly89mxJJXDC3gN51skCPYWg qOHnJYmF8gLuqetLwb5bB44= X-Google-Smtp-Source: ABdhPJygYBJKYJFujhKJtGYj/sIM/7VF9BtAYwJyYx2TAp9yLJhnpvaLsSTl3wqkiacMVMNw2Kp/zQ== X-Received: by 2002:a17:90a:734b:: with SMTP id j11mr10996145pjs.108.1590065339983; Thu, 21 May 2020 05:48:59 -0700 (PDT) Received: from localhost ([2409:10:2e40:5100:6e29:95ff:fe2d:8f34]) by smtp.gmail.com with ESMTPSA id q189sm4680196pfc.112.2020.05.21.05.48.58 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 21 May 2020 05:48:59 -0700 (PDT) From: Sergey Senozhatsky X-Google-Original-From: Sergey Senozhatsky Date: Thu, 21 May 2020 21:48:56 +0900 To: Andrew Morton Cc: Sergey Senozhatsky , Joe Perches , Chenggang Wang , linux-kernel@vger.kernel.org, Petr Mladek , Steven Rostedt Subject: Re: [RFC PATCH 2/2] init: Allow multi-line output of kernel command line Message-ID: <20200521124856.GC755@jagdpanzerIV.localdomain> References: <2b3832fed9370f0f8dfd1ea33dddb1d05a36e265.1589916689.git.joe@perches.com> <20200520044127.GB938@jagdpanzerIV.localdomain> <20200520121000.GF520@jagdpanzerIV.localdomain> <19a8c717f8d9dc76f2b09e6dd19f3fbb71bf29c5.camel@perches.com> <20200520180028.8fc1b7890774c6f92a6c2623@linux-foundation.org> <20200521043628.GB755@jagdpanzerIV.localdomain> <20200520214007.86f36f61e1fc0329b66758ed@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200520214007.86f36f61e1fc0329b66758ed@linux-foundation.org> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On (20/05/20 21:40), Andrew Morton wrote: > > On (20/05/20 18:00), Andrew Morton wrote: > > [..] > > > 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. > > > > Can you point me at some examples? > > > > ./arch/powerpc/kernel/udbg.c: printk("%s", s); > ./arch/powerpc/xmon/nonstdio.c: printk("%s", xmon_outbuf); > ./arch/um/os-Linux/drivers/ethertap_user.c: printk("%s", output); > ./arch/um/os-Linux/drivers/ethertap_user.c: printk("%s", output); > ./arch/um/os-Linux/drivers/tuntap_user.c: printk("%s", out Hmm, interesting. output = uml_kmalloc(UM_KERN_PAGE_SIZE, UM_GFP_KERNEL); read_output(fd, output, UM_KERN_PAGE_SIZE); printk("%s", output); kfree(output); > etc. > > My point is, if we created a length-unlimited puts() function for printing the > kernel command line, it could be reused in such places A function that prints the kernel command line is a bit different in the way that we can split command line arguments - they are space separated, which is very convenient - so we would pr_cont() parts of command line individually. This has an advantage that we won't \r\n in the middle of the parameter. Looking at examples, it seems that most of them simply do a single printk() with arbitrary sized buffers that contain random data, not necessarily space separated. So same problem - we truncate messages (maybe?), but needs a slightly different solution (?). -ss