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=-5.4 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 BCD80C4363A for ; Fri, 23 Oct 2020 15:27:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6359421D47 for ; Fri, 23 Oct 2020 15:27:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S465806AbgJWP1Q (ORCPT ); Fri, 23 Oct 2020 11:27:16 -0400 Received: from mail-pg1-f196.google.com ([209.85.215.196]:43595 "EHLO mail-pg1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S462196AbgJWP1Q (ORCPT ); Fri, 23 Oct 2020 11:27:16 -0400 Received: by mail-pg1-f196.google.com with SMTP id r10so1505942pgb.10; Fri, 23 Oct 2020 08:27:15 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=BLVFBML2Vwax1XyDeMppx9C3lOBX85F9Q67T1CeljKY=; b=PW7flJX+qlxsMTWjY8G8NIIrIK34rAfZdykbHO3sgOht/xqz678v2jiPwLqHDgSnwY WuBYNtZCVdTHlvLqUB8yhJkcXTc/LsSZHUDtU7TyVdz6JMsb5nhBV6F9m/Xel+TkQ3j5 d+Gj2pWOr24Rnsylx6FB0A2hqRI3oephUxKE2kPN/PwaUf/TU9Nxs8yy/hLNQcckKdbP pw14y4nGg8Fss320J1DzKuY866UlSBJ9VfZGulCian5EaHnZo0moL13tz5vyw5QzWBAR tn0qi29TrBaqYSAn9VAB0iMgxFmTe/Qdg+VOLMwP7NX6ylFPWfsXgGBESwodNCsSLzmp 0gmg== X-Gm-Message-State: AOAM530F7pTzSMc2ZGovDX5V2q8hC2FCALIz/1P6r0UhXnpNppnTE8Ko gF9eBgVruTrs76vmyO5azxSdE8NAxV1KPw== X-Google-Smtp-Source: ABdhPJxKO0uOkptR8CUzV7g074wD+rgIs0xpvIRLo8ZQpNiEBUz3XTXUQ4A03M1xKLM9YaBFCJL6oA== X-Received: by 2002:a17:90a:e997:: with SMTP id v23mr3037101pjy.195.1603466834441; Fri, 23 Oct 2020 08:27:14 -0700 (PDT) Received: from [192.168.50.110] (c-73-241-217-19.hsd1.ca.comcast.net. [73.241.217.19]) by smtp.gmail.com with ESMTPSA id u21sm2243209pfk.89.2020.10.23.08.27.11 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 23 Oct 2020 08:27:12 -0700 (PDT) Subject: Re: [PATCH] scsi: ufs: make sure scan sequence for multiple hosts To: Chanho Park , jejb@linux.ibm.com, martin.petersen@oracle.com Cc: alim.akhtar@samsung.com, avri.altman@wdc.com, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org References: <20201020070516.129273-1-chanho61.park@samsung.com> <7fafcc82-2c42-8ef5-14a6-7906b5956363@acm.org> <000a01d6a761$efafcaf0$cf0f60d0$@samsung.com> <0a5eb555-af2a-196a-2376-01dc4a92ae0c@acm.org> <008a01d6a830$1a109800$4e31c800$@samsung.com> From: Bart Van Assche Message-ID: <6e204521-74e4-cc6c-27e7-3a290c492793@acm.org> Date: Fri, 23 Oct 2020 08:27:10 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <008a01d6a830$1a109800$4e31c800$@samsung.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/21/20 9:59 PM, Chanho Park wrote: >> Please use udev or systemd instead of adding code in the UFS driver that >> is >> not necessary when udev or systemd is used. >> > > What I mentioned was how it can be handled when we mount rootfs directly from kernel. > > 1) kernel -> initramfs (mount root) -> systemd > 2) kernel (mount root) -> systemd > -> In this case, we normally use root=/dev/sda1 from kernel commandline to mount the rootfs. > > Like fstab can support legacy node mount, ufs driver also needs to provide > an option for using the permanent legacy node. If you're really worry about > adding a new codes for all UFS driver, we can put this as controller specific> or optional feature. The only code that should occur in the UFS driver is code that is specific to UFS devices. Since the functionality in this patch is not UFS specific, it should be added elsewhere. Additionally, since this functionality can be implemented easily in user space, I think it should be implemented in user space instead of in the kernel. Even when not using systemd or udev, it is easy to implement a loop that waits until a certain LUN or WWID appears. Bart.