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 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D0406C63684 for ; Wed, 26 Jan 2022 17:16:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XPQZUxJnS1AhgoTuyOTJHtmC/GkSaDgaBjoJlTyaC2I=; b=3lnc4pv7xm93CZZKPrrCiApV+Z AIlurIeYkqGBXNjC0N7SWolUFLwEXrpT+OWbHCXI+jNxgBg+UZkiamjYwnsxfOmOG9bT5arFIs6Fg gjOCjmtDEP2FoZcB8lR/eFnPcP0U5yR2A+c8PhptLN+uJM0bfhG3GPl4j378U3+edvgoBmOBnSHX5 qvopPdYUSh415vnT23/415w7Ukc15KUyOlbyyc5GtVvCHrij7VXjC0Uns90r8VjlPM+1MZrzfG216 ztrtooX3YjKdpa2Y5dXVPC3kQn3lNrU8euNotq3NGXH1tj81QziahsbS8LHdTFh5iZvGL47yFEwao XZplqcQA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nCluA-00Cvyp-3a; Wed, 26 Jan 2022 17:16:22 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nCl9D-00CdVk-Ay for linux-nvme@lists.infradead.org; Wed, 26 Jan 2022 16:27:52 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 9E7E768AFE; Wed, 26 Jan 2022 17:27:47 +0100 (CET) Date: Wed, 26 Jan 2022 17:27:47 +0100 From: Christoph Hellwig To: Chaitanya Kulkarni Cc: linux-nvme@lists.infradead.org, hch@lst.de, kbusch@kernel.org, sagi@grimberg.me, Chaitanya Kulkarni Subject: Re: [PATCH 0/3] nvmet: add buffered_io support for bdev-ns Message-ID: <20220126162747.GB31431@lst.de> References: <20220119072038.3942-1-chaitanyak@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220119072038.3942-1-chaitanyak@nvidia.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-20220126_082751_593000_2A39AE54 X-CRM114-Status: GOOD ( 12.21 ) 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: , Sender: "Linux-nvme" Errors-To: linux-nvme-bounces+linux-nvme=archiver.kernel.org@lists.infradead.org Shouldn't something like the patch below be all we need to use buffered I/O on a block device? diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c index 70ca9dfc1771a..7d9da2f77b83a 100644 --- a/drivers/nvme/target/io-cmd-bdev.c +++ b/drivers/nvme/target/io-cmd-bdev.c @@ -76,6 +76,10 @@ int nvmet_bdev_ns_enable(struct nvmet_ns *ns) { int ret; + /* force fallback to the file backend for buffered I/O mode */ + if (ns->buffered_io) + return -ENOTBLK; + ns->bdev = blkdev_get_by_path(ns->device_path, FMODE_READ | FMODE_WRITE, NULL); if (IS_ERR(ns->bdev)) {