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=-0.8 required=3.0 tests=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 2C5F1C43603 for ; Mon, 9 Dec 2019 18:39:20 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id F0546205C9 for ; Mon, 9 Dec 2019 18:39:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726483AbfLISjT (ORCPT ); Mon, 9 Dec 2019 13:39:19 -0500 Received: from bhuna.collabora.co.uk ([46.235.227.227]:48286 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726365AbfLISjT (ORCPT ); Mon, 9 Dec 2019 13:39:19 -0500 Received: from localhost (unknown [IPv6:2610:98:8005::247]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: krisman) by bhuna.collabora.co.uk (Postfix) with ESMTPSA id 7E35D290CD3; Mon, 9 Dec 2019 18:39:16 +0000 (GMT) From: Gabriel Krisman Bertazi To: Lee Duncan Cc: "cleech\@redhat.com" , "martin.petersen\@oracle.com" , "linux-scsi\@vger.kernel.org" , "open-iscsi\@googlegroups.com" , Bharath Ravi , "kernel\@collabora.com" , "Dave Clausen" , Nick Black , Vaibhav Nagarnaik , Anatol Pomazau , Tahsin Erdogan , Frank Mayhar , Junho Ryu , Khazhismel Kumykov Subject: Re: [PATCH] iscsi: Perform connection failure entirely in kernel space Organization: Collabora References: <20191209182054.1287374-1-krisman@collabora.com> <9865d3ff-676f-7502-d1a5-dd41cb940cd3@suse.com> Date: Mon, 09 Dec 2019 13:39:13 -0500 In-Reply-To: <9865d3ff-676f-7502-d1a5-dd41cb940cd3@suse.com> (Lee Duncan's message of "Mon, 9 Dec 2019 18:29:14 +0000") Message-ID: <85h829l4xa.fsf@collabora.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-scsi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org Lee Duncan writes: > On 12/9/19 10:20 AM, Gabriel Krisman Bertazi wrote: >> 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 implements an optional feature in the iscsi module, to >> perform the connection failure 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 perform recovery >> procedures if applicable. > > > I don't suppose you've tested how this plays with the daemon, when present? Hello, Yes, I did. It seemed to work properly over TCP. The stop calls are serialized by the rx_mutex, whoever gets it first, gets the job done. The second should return immediately since the socket is no longer there. What am I missing? -- Gabriel Krisman Bertazi