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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 7DADCC31E5B for ; Tue, 18 Jun 2019 00:36:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5A6A520873 for ; Tue, 18 Jun 2019 00:36:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726696AbfFRAf6 (ORCPT ); Mon, 17 Jun 2019 20:35:58 -0400 Received: from smtp.infotech.no ([82.134.31.41]:43846 "EHLO smtp.infotech.no" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725829AbfFRAf6 (ORCPT ); Mon, 17 Jun 2019 20:35:58 -0400 Received: from localhost (localhost [127.0.0.1]) by smtp.infotech.no (Postfix) with ESMTP id C41612041CB; Tue, 18 Jun 2019 02:35:55 +0200 (CEST) X-Virus-Scanned: by amavisd-new-2.6.6 (20110518) (Debian) at infotech.no Received: from smtp.infotech.no ([127.0.0.1]) by localhost (smtp.infotech.no [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 4O3UQmvajfYm; Tue, 18 Jun 2019 02:35:53 +0200 (CEST) Received: from [192.168.48.23] (host-45-58-224-183.dyn.295.ca [45.58.224.183]) by smtp.infotech.no (Postfix) with ESMTPA id B3A1220418A; Tue, 18 Jun 2019 02:35:52 +0200 (CEST) Reply-To: dgilbert@interlog.com Subject: Re: [PATCH v1] scsi: Don't select SCSI_PROC_FS by default To: Bart Van Assche , Marc Gonzalez , James Bottomley , Martin Petersen Cc: SCSI , LKML , Christoph Hellwig References: <2de15293-b9be-4d41-bc67-a69417f27f7a@free.fr> <621306ee-7ab6-9cd2-e934-94b3d6d731fc@acm.org> From: Douglas Gilbert Message-ID: Date: Mon, 17 Jun 2019 20:35:50 -0400 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <621306ee-7ab6-9cd2-e934-94b3d6d731fc@acm.org> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-CA Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019-06-17 5:11 p.m., Bart Van Assche wrote: > On 6/12/19 6:59 AM, Marc Gonzalez wrote: >> According to the option's help message, SCSI_PROC_FS has been >> superseded for ~15 years. Don't select it by default anymore. >> >> Signed-off-by: Marc Gonzalez >> --- >>   drivers/scsi/Kconfig | 3 --- >>   1 file changed, 3 deletions(-) >> >> diff --git a/drivers/scsi/Kconfig b/drivers/scsi/Kconfig >> index 73bce9b6d037..8c95e9ad6470 100644 >> --- a/drivers/scsi/Kconfig >> +++ b/drivers/scsi/Kconfig >> @@ -54,14 +54,11 @@ config SCSI_NETLINK >>   config SCSI_PROC_FS >>       bool "legacy /proc/scsi/ support" >>       depends on SCSI && PROC_FS >> -    default y >>       ---help--- >>         This option enables support for the various files in >>         /proc/scsi.  In Linux 2.6 this has been superseded by >>         files in sysfs but many legacy applications rely on this. >> -      If unsure say Y. >> - >>   comment "SCSI support type (disk, tape, CD-ROM)" >>       depends on SCSI > > Hi Doug, > > If I run grep "/proc/scsi" over the sg3_utils source code then grep reports 38 > matches for that string. Does sg3_utils break with SCSI_PROC_FS=n? First, the sg driver. If placing #undef CONFIG_SCSI_PROC_FS prior to the includes in sg.c is a valid way to test that then the answer is no. Ah, but you are talking about sg3_utils . Or are you? For sg3_utils: $ find . -name '*.c' -exec grep "/proc/scsi" {} \; -print static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio"; ./src/sg_read.c static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio"; ./src/sgp_dd.c static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio"; ./src/sgm_dd.c static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio"; ./src/sg_dd.c "'echo 1 > /proc/scsi/sg/allow_dio'\n", q_len, dirio_count); ./testing/sg_tst_bidi.c static const char * proc_allow_dio = "/proc/scsi/sg/allow_dio"; ./examples/sgq_dd.c That is 6 (not 38) by my count. Those 6 are all for direct IO (see below) which is off by default. I suspect old scanning utilities like sg_scan and sg_map might also use /proc/scsi/* . That is one reason why I wrote lsscsi. However I can't force folks to use lsscsi. As a related example, I still get bug reports for sginfo which I inherited from Eric Youngdale. If I was asked to debug a problem with the sg driver in a system without CONFIG_SCSI_PROC_FS defined, I would decline. The absence of /proc/scsi/sg/debug would be my issue. Can this be set up to do the same thing: cat /sys/class/scsi_generic/debug ? Is that breaking any sysfs rules? Also folks who rely on this to work: cat /proc/scsi/sg/devices 0 0 0 0 0 1 255 0 1 0 0 0 1 0 1 255 0 1 0 0 0 2 0 1 255 0 1 would be disappointed. Further I note that setting allow_dio via /proc/scsi/sg/allow_dio can also be done via /sys/module/sg/allow_dio . So that would be an interface breakage, but with an alternative. Doug Gilbert