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[2620:137:e000::1:20]) by mx.google.com with ESMTP id ee32-20020a056402292000b0046fbd084ea6si1443667edb.142.2022.12.15.23.56.25; Thu, 15 Dec 2022 23:56:41 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@infradead.org header.s=bombadil.20210309 header.b=m0+OLoWt; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229912AbiLPHNx (ORCPT + 68 others); Fri, 16 Dec 2022 02:13:53 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41386 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230042AbiLPHNO (ORCPT ); Fri, 16 Dec 2022 02:13:14 -0500 Received: from bombadil.infradead.org (bombadil.infradead.org [IPv6:2607:7c80:54:3::133]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 375C72E68C; Thu, 15 Dec 2022 23:11:30 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=rbdP76tLSLd0zXbJ7Ayy7yAOCBynRgWdD+HyAwvTvH4=; b=m0+OLoWtPz8unWkSr4hKaAJVp7 FCyWa6+VyYFNVyBxJLY/OYIvymTzNjmoPqxgATo04jrLoz55cV6sENFU0SpPjK3SEtABL/MBJ+Cg1 /jd9QApAUcLaqH7FJt5TLDU2Uh9MP5A6bQjweSuCrenwOMOpCIQ3IhppLY31fLPLIMCyFEHgBJPn+ 8e59gq9nDL2lQNjwRul99jyClPji6Lu6z3MH4b+SaqtXxGHzDliH2ZDI9bj0drxvpqxzfjIEqkCGH I6UcdeKfCzvV3S2NXQz2PQU804l4yQa1hzThOOu28DGd6MaNMk4iy3zlT5HJgaNlf/fdrjjqy/vhl cDSZ8IRQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1p64sD-00DKqT-10; Fri, 16 Dec 2022 07:11:13 +0000 Date: Thu, 15 Dec 2022 23:11:13 -0800 From: Christoph Hellwig To: Ulrich Windl Cc: haowenchao@huawei.com, open-iscsi , linfeilong@huawei.com, liuzhiqiang26@huawei.com, jejb@linux.ibm.com, martin.petersen@oracle.com, michael.christie@oracle.com, Chris Leech , Lee Duncan , linux-kernel@vger.kernel.org, linux-scsi@vger.kernel.org Subject: Re: Antw: [EXT] Re: [PATCH 0/2] scsi:donot skip lun if inquiry returns PQ=1 for all hosts Message-ID: References: <20221214070846.1808300-1-haowenchao@huawei.com> <639AD5C0020000A100050749@gwsmtp.uni-regensburg.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <639AD5C0020000A100050749@gwsmtp.uni-regensburg.de> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html X-Spam-Status: No, score=-4.4 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_MED,SPF_HELO_NONE, SPF_NONE autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Dec 15, 2022 at 09:07:28AM +0100, Ulrich Windl wrote: > Actusally I have no idea, but as a user of FC SAN systems I can remember a case when a storage system had to present a dummy LUN0 to enable hosts to find other LUNs (while LUN0 was never actually used). Maybe the client code was imperfect, I don't know. Ignoring some of the well known LU bits that never really became practically relevant, lun0 is needed to use the REPORT_LUNS command to scane for the other logical units. But unless the PQ says it actually is a valid logic unit, we never add a sdev for it.