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=-5.3 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,URIBL_BLOCKED,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 03D83C43461 for ; Tue, 8 Sep 2020 08:50:10 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 8F3A6215A4 for ; Tue, 8 Sep 2020 08:50:09 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="LQQqGWZW" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8F3A6215A4 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=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject: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=XemOx85sTeohGxZELSpC4IFaZl2du0d0LWy8M7twxjc=; b=LQQqGWZWF+qzx2LQfentVqwdc O2n0T7071OhfKZdVCnpYYfKkLgZU3LYhambXPXn9JTAIc3bDMHJ+b8/LntZGx7S7L6AfaOgeAwDBj xLQL4l4HwVi2jW+X9eD7ULzPI/jbM+btmZB+4hqszOn2HwXkt/yTjwWIEfrOWMKUqogeFUffV7aVP tbbSip7fdn1LCh8NfU79v8lvjhd5bGrR5piwF3KHBc2J9/eQSte1w7DfvTmGGrZTIdvBz+VLs2mnd GICeXCG7oOEgjVK3OGXO/oFXjyROOOEAU9B7PjCkAsiLxSv3ui0yU8peN5bSS6eeL5duMpMvYYm+J azFfH6wFQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFZKH-0001Ja-7M; Tue, 08 Sep 2020 08:50:05 +0000 Received: from verein.lst.de ([213.95.11.211]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1kFZKD-0001Ht-9F for linux-nvme@lists.infradead.org; Tue, 08 Sep 2020 08:50:02 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 60C2268AFE; Tue, 8 Sep 2020 10:49:58 +0200 (CEST) Date: Tue, 8 Sep 2020 10:49:58 +0200 From: Christoph Hellwig To: Chaitanya Kulkarni Subject: Re: [PATCH 1/3] nvme: decouple nvme_ctrl_get_by_path() Message-ID: <20200908084958.GA17413@lst.de> References: <20200904023929.5320-1-chaitanya.kulkarni@wdc.com> <20200904023929.5320-2-chaitanya.kulkarni@wdc.com> <16dc2193-9830-6184-e7f6-ceaca5f0aaf0@deltatee.com> <20200905072018.GA13403@lst.de> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: 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-20200908_045001_452833_E09F5A17 X-CRM114-Status: GOOD ( 18.17 ) X-BeenThere: linux-nvme@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "kbusch@kernel.org" , Logan Gunthorpe , Christoph Hellwig , "linux-nvme@lists.infradead.org" , "sagi@grimberg.me" 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 Sat, Sep 05, 2020 at 10:57:42PM +0000, Chaitanya Kulkarni wrote: > On 9/5/20 00:20, Christoph Hellwig wrote: > >> I still don't really like this idea. No need to keep a reference to a > >> whole other file. > > File reference open/close is coupled with ctrl refcnt and module refcnt. > What is a problem with keeping the file reference open ? > > > We could still lift the filp_open into the caller, but drop the file > > reference right after we got the controller reference. > > > > The file open call gets the ctrl and module reference atomically and on > close release the module and ctrl reference respectively. > > If dropping the file reference means closing the file then it will lead > to loosing the module and ctrl reference. Not if you grab an extra reference before closing it. > That also means, moving the references get/put out of > nvme_dev_open()/nvme_dev_release() in host-core, it will fix the problem > only for the passthru case. Having done it in the core takes care of the > all the cases if any. I don't see why that is an either/or instead of doing both. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme