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,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 7DD09C433E9 for ; Thu, 3 Sep 2020 16:23:17 +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 42ACE20775 for ; Thu, 3 Sep 2020 16:23:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="jwTo44EI" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 42ACE20775 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=1vW9YBtKgZDr7zUcxZtpU4O5i6jGFXil8a1Cu0iPOSU=; b=jwTo44EIo6hTA25iK5ViEs5ZP LhkQbPiuRO+vi0y/7cnho49DLWUhfi+bUJEU5c8ch2ZbL5LCYsrncjWRWfd4tadbK9a6s/Oh00gbe rlLOMpL2182/fuDJVbHrKszg73+Biz1ewlO9sf8XTNqA6I3bxxq3zpx5agNcXA1Qf/M38DHQYWcRZ UiGsXYd1l1OC7v4qRf+g49JlXKDmccboEcNkw3B+WZzsq1RrXnTypYydd5ukyfPonE2VLx7P/0V0p gXEfT3R/cRqEjTBzs/BHKrFXLjbBkNngycNHEKVSj7L9cZgBfnZjYWiItyxPXj2udnkVyKdIglvzI Em1ZYk8Ew==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1kDs14-00075G-7a; Thu, 03 Sep 2020 16:23:14 +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 1kDs10-00073c-S6 for linux-nvme@lists.infradead.org; Thu, 03 Sep 2020 16:23:11 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 3B1D568CEC; Thu, 3 Sep 2020 18:23:09 +0200 (CEST) Date: Thu, 3 Sep 2020 18:23:08 +0200 From: Christoph Hellwig To: Chaitanya Kulkarni Subject: Re: [PATCH V2 11/12] nvmet: use minimized version of blk_rq_append_bio Message-ID: <20200903162308.GF25423@lst.de> References: <20200831222707.35611-1-chaitanya.kulkarni@wdc.com> <20200831222707.35611-12-chaitanya.kulkarni@wdc.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20200831222707.35611-12-chaitanya.kulkarni@wdc.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-20200903_122311_042042_B0447D6E X-CRM114-Status: GOOD ( 12.80 ) 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, logang@deltatee.com, hch@lst.de, 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 Mon, Aug 31, 2020 at 03:27:06PM -0700, Chaitanya Kulkarni wrote: > The function blk_rq_append_bio() is a genereric API written for all > types driver (having bounce buffers) and different context (where > request is already having a bio i.e. rq->bio != NULL). > > It does mainly three things: calculating the segments, bounce queue and > if req->bio == NULL call blk_rq_bio_prep() or handle low level merge() > case. > > The NVMe PCIe driver does not use the queue bounce mechanism. In order > to find this out for each request processing in the passthru > blk_rq_append_bio() does extra work in the fast path for each request. We need to be able to deal with all transport drivers. None of them uses bounce buffering, but the changelog needs to be correct. _______________________________________________ Linux-nvme mailing list Linux-nvme@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-nvme