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 C5A57C43334 for ; Fri, 8 Jul 2022 05:00:56 +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=0A4ennnc2F+IoJyjjEUp5ofCfIPhj/ZHG/krHpep8B4=; b=1Zj2rTDELFLAY0VIOgZBGCY0gJ b14+xt8v2tt52aKbJVPSTm4uYp1kskowH1JWll6DDkdiucbyLQM6JW9WgmKlb3NL9OcaH/T2ZUxYP mIw3Ogz9JhV36d5OdBfPYxtXtEMgbPNTwSl4rvz7D4A6M0P4K1mZMQPr9WfS8lN1PJt8m/rp5/+Vc uXcyS/hB+jBWe5/6FCZ8TV8ZXCxD0PjX4D09k1MZMEBEjFMMIF8hPgfC3SyXeA74hpKDcFekWGuD+ aeC5CjAjSlAGbf+IyJHKGneRFIq2HJ0Nq8IPsg2CXy1mhlLITB8LB/uGVqP4plWRC/73TIlBkeONn hqd9JuPQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1o9g6m-001lZQ-4z; Fri, 08 Jul 2022 05:00:52 +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 1o9g6j-001lW5-16 for linux-nvme@lists.infradead.org; Fri, 08 Jul 2022 05:00:50 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 7017167373; Fri, 8 Jul 2022 07:00:38 +0200 (CEST) Date: Fri, 8 Jul 2022 07:00:38 +0200 From: Christoph Hellwig To: Caleb Sander Cc: Sagi Grimberg , Keith Busch , Jens Axboe , Christoph Hellwig , linux-nvme@lists.infradead.org Subject: Re: [PATCH v2] nvme-tcp: use in-capsule data for I/O connect Message-ID: <20220708050038.GA15655@lst.de> References: <4cfe8116-bb6c-735d-0bb3-ce5e2612505b@grimberg.me> <20220707211245.3989107-1-csander@purestorage.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220707211245.3989107-1-csander@purestorage.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-20220707_220049_267137_BD972CEB X-CRM114-Status: GOOD ( 14.69 ) 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 On Thu, Jul 07, 2022 at 03:12:45PM -0600, Caleb Sander wrote: > >From the NVMe/TCP spec: > > The maximum amount of in-capsule data for Fabrics and Admin Commands > > is 8,192 bytes ... NVMe/TCP controllers must support in-capsule data > > for Fabrics and Admin Command Capsules > > Currently, command data is only sent in-capsule on the admin queue > or I/O queues that indicate support for it. > Send fabrics command data in-capsule for I/O queues too to avoid > needing a separate H2CData PDU for the connect command. While I'm fine with this change, can you please state here why this is important? Is there a use case where it really matters? A controller that is unhappy if this doesn't happen?