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=-5.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, 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 C584BC433DB for ; Fri, 19 Mar 2021 14:06:01 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 396D764EF6 for ; Fri, 19 Mar 2021 14:06:01 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 396D764EF6 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:Cc:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=uc6VUz9GZlpTIAfjyWx4vuULgttNehpSaUcVyhDgPU0=; b=d1ONmUDDSGSB4XrklI3sEWXLw 6GqnpXnMSxKvPa/zAqomploABwIdmI+2etMR9kVOm/IVuDCBdhDtQR4VgMM7XQV7LTbcPfdThAc/J +2+sQ3dhweapRCbqFlNkZE8tqnTKWfZWD/oM9CkwEHD8i4Kif++8vYPQbfMtfzRSXBE3JWkBdr8sk SzKrYA+LGXckti+HreGSgKFgHUWC6qmO+hESmcJBI6iTw11CfS1g8YlASygwF1z1afBHIWuNM4csp DNQ8CewM0+plf/6pt9bX+aBEDQvs3EEdA2oQZOFYmxnRqRBS0zBk5C0tZZtVOD69PxdS23lLDMLs4 a+8sms57Q==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lNFkw-007W3m-Up; Fri, 19 Mar 2021 14:05:39 +0000 Received: from verein.lst.de ([213.95.11.211]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lNFkt-007W3K-0u for linux-nvme@lists.infradead.org; Fri, 19 Mar 2021 14:05:36 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 5518568BFE; Fri, 19 Mar 2021 15:05:32 +0100 (CET) Date: Fri, 19 Mar 2021 15:05:32 +0100 From: Christoph Hellwig To: Keith Busch Cc: Sagi Grimberg , Chao Leng , Christoph Hellwig , linux-nvme@lists.infradead.org, Chaitanya Kulkarni Subject: Re: [PATCH 0/3 rfc] Fix nvme-tcp and nvme-rdma controller reset hangs Message-ID: <20210319140532.GA7019@lst.de> References: <59f7a030-ea33-5c31-3c18-197c5a12e982@grimberg.me> <17b15849-f0f3-af61-113f-0eb717e96f0f@huawei.com> <20210317065910.GC14498@lst.de> <2e391aae-58c7-b8f7-1a9e-d7ad5bb3f8f3@huawei.com> <6c085430-cc10-a2fd-56ee-a360109c940a@grimberg.me> <55142c25-9a70-08a0-d46a-cad21da59d19@huawei.com> <7b7d5223-ddaf-eb88-f112-02834f8c8f93@grimberg.me> <20210318191613.GB31675@redsun51.ssa.fujisawa.hgst.com> <20210318215256.GC31675@redsun51.ssa.fujisawa.hgst.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20210318215256.GC31675@redsun51.ssa.fujisawa.hgst.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210319_140535_200718_8FCD0F91 X-CRM114-Status: GOOD ( 18.06 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org On Fri, Mar 19, 2021 at 06:52:56AM +0900, Keith Busch wrote: > Having submit_bio() return the enter status was where I was going with > this, but the recursive handling makes this more complicated than I > initially thought. Note that the recursion handling is not really required for nvme-multipath. I have some plans to actually kill it off entirely for blk-mq submissions, which needs work on the bounce buffering and bio splitting code, but should not be too hard. > If you use the NOWAIT flag today with a freezing queue, the IO will end > with BLK_STS_AGAIN and punt retry handling to the application. I'm > guessing you don't want that to happen, so a little more is required for > this idea. We really should not use NOWAIT but a flag that only escapes the freeze protection. I think REQ_FAILFAST_DRIVER should probably be changed to trigger that, but even if not we could add a new flag. > Since it's an error path, perhaps a block operations callback is okay? > Something like this compile tested patch? We really should not need an indirection. And more importantly I don't think the consuming driver cares, it really is the submitting one. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme