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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY 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 9086DC33CAF for ; Thu, 16 Jan 2020 03:52:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5FB72207E0 for ; Thu, 16 Jan 2020 03:52:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="WiFIwo6Q" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729736AbgAPDwo (ORCPT ); Wed, 15 Jan 2020 22:52:44 -0500 Received: from userp2120.oracle.com ([156.151.31.85]:47826 "EHLO userp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728925AbgAPDwn (ORCPT ); Wed, 15 Jan 2020 22:52:43 -0500 Received: from pps.filterd (userp2120.oracle.com [127.0.0.1]) by userp2120.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00G3nK6b118247; Thu, 16 Jan 2020 03:52:28 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=to : cc : subject : from : references : date : in-reply-to : message-id : mime-version : content-type; s=corp-2019-08-05; bh=yNzd9lPrWUYLF0Y/Aks4FJNxeyBhI5jJGY+hr0rr/5M=; b=WiFIwo6Qjfgd7v07XzhkeUKXHHLFnms8H7njt3tcQpFq/uk5LtqNwx3sqtCQJR7vyeYv EGc/ASbcDLvPoROCxOfnPPQVihv14TPmiU8N1a9vI8wZ8gM+YWBYHnfUYPSgx0xWofs4 FB6PzgPa5emTfv3ZiH5Du5A8uFTlJLtQuzUXFdcmhEZ6tG/ls7+8acNgm30DOeFiEjNZ tzqT/klQ2m/eLDhxt8gSq2wIn7axf5VoTZThW7npNpyXDEnQKJsICnAJ1Vz6aj/i06Nz W/SzKNNI2gRfQlQv1ORCrIWDTjxkKq4LEJ/WOfcPc3C9x8dIiJk0dKw27y4voLeseSLP 9Q== Received: from aserp3030.oracle.com (aserp3030.oracle.com [141.146.126.71]) by userp2120.oracle.com with ESMTP id 2xf73yr12u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 16 Jan 2020 03:52:27 +0000 Received: from pps.filterd (aserp3030.oracle.com [127.0.0.1]) by aserp3030.oracle.com (8.16.0.27/8.16.0.27) with SMTP id 00G3nVtT161562; Thu, 16 Jan 2020 03:52:27 GMT Received: from aserv0122.oracle.com (aserv0122.oracle.com [141.146.126.236]) by aserp3030.oracle.com with ESMTP id 2xj61kufgw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Thu, 16 Jan 2020 03:52:27 +0000 Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by aserv0122.oracle.com (8.14.4/8.14.4) with ESMTP id 00G3qP2U007839; Thu, 16 Jan 2020 03:52:25 GMT Received: from ca-mkp.ca.oracle.com (/10.159.214.123) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Wed, 15 Jan 2020 19:52:25 -0800 To: lduncan@suse.com Cc: Gabriel Krisman Bertazi , Khazhismel Kumykov , Chris Leech , jejb@linux.ibm.com, "Martin K. Petersen" , "'Khazhismel Kumykov' via open-iscsi" , linux-scsi@vger.kernel.org, Bharath Ravi , kernel@collabora.com, Mike Christie , Bart Van Assche , Dave Clausen , Nick Black , Vaibhav Nagarnaik , Anatol Pomazau , Tahsin Erdogan , Frank Mayhar , Junho Ryu Subject: Re: [PATCH v4] iscsi: Perform connection failure entirely in kernel space From: "Martin K. Petersen" Organization: Oracle Corporation References: <20191226204746.2197233-1-krisman@collabora.com> <85ftgx7mlr.fsf@collabora.com> <85r20g2vfw.fsf_-_@collabora.com> Date: Wed, 15 Jan 2020 22:52:21 -0500 In-Reply-To: <85r20g2vfw.fsf_-_@collabora.com> (Gabriel Krisman Bertazi's message of "Fri, 03 Jan 2020 14:26:11 -0500") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1.92 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9501 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=1 malwarescore=0 phishscore=0 bulkscore=0 spamscore=0 mlxscore=0 mlxlogscore=868 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001160029 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9501 signatures=668685 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 priorityscore=1501 malwarescore=0 suspectscore=1 phishscore=0 bulkscore=0 spamscore=0 clxscore=1011 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=914 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1911140001 definitions=main-2001160029 Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org > Please consider the v4 below with the lock added. Lee: Please re-review this given the code change. > From: Bharath Ravi > > Connection failure processing depends on a daemon being present to (at > least) stop the connection and start recovery. This is a problem on a > multipath scenario, where if the daemon failed for whatever reason, the > SCSI path is never marked as down, multipath won't perform the > failover and IO to the device will be forever waiting for that > connection to come back. > > This patch performs the connection failure entirely inside the kernel. > This way, the failover can happen and pending IO can continue even if > the daemon is dead. Once the daemon comes alive again, it can execute > recovery procedures if applicable. -- Martin K. Petersen Oracle Linux Engineering