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 D5A9BC4345F for ; Thu, 2 May 2024 07:12:32 +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=tlVq0zV7PPRyL4TfrFkMTscYtH9rzwR77WV4fpfEQ9s=; b=uALzzm1oe8nvI8tSRva/mHwohu fCbs81m8xPjLmewlZbramiwFIZLXGZ/TKdwLrHJ0Y9Xcc/hLamipSP9DYDfTTyBzwYI20A59UNVxG csMcxc/HEgWjsJN6IAWhS5w4BqVzcslV264VHnBhjqCFv+fHluQt/Fl9LiFi3LlzstzfY8BajNekL mPgJE/0oHWnpi51Djf3tP4i/Ak433vvvV479VwYE042Rc2PQAomuqQIWxfy1jWX+liT+oBjhvZXyP 7eJsfZZok9iPtJkCCiLkpf3CO2w1Flmmh2uGFQ1T6BngjliI2Yvxsx6zJn9ks1R3fIT8i+lbsz04f KSY91uZQ==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1s2QcI-0000000Blb7-3I1D; Thu, 02 May 2024 07:12:30 +0000 Received: from verein.lst.de ([213.95.11.211]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1s2QcG-0000000BlaV-03BF for linux-nvme@lists.infradead.org; Thu, 02 May 2024 07:12:29 +0000 Received: by verein.lst.de (Postfix, from userid 2407) id 496A1227A87; Thu, 2 May 2024 09:12:22 +0200 (CEST) Date: Thu, 2 May 2024 09:12:21 +0200 From: Christoph Hellwig To: Kanchan Joshi Cc: Christoph Hellwig , axboe@kernel.dk, martin.petersen@oracle.com, kbusch@kernel.org, brauner@kernel.org, asml.silence@gmail.com, dw@davidwei.uk, io-uring@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, gost.dev@samsung.com, Anuj Gupta Subject: Re: [PATCH 04/10] block: avoid unpinning/freeing the bio_vec incase of cloned bio Message-ID: <20240502071221.GA31379@lst.de> References: <20240425183943.6319-1-joshi.k@samsung.com> <20240425183943.6319-5-joshi.k@samsung.com> <20240427070508.GD3873@lst.de> <03cb6ac3-595f-abb1-324b-647ed84cfe6b@samsung.com> <20240429170929.GB31337@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii 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-20240502_001228_357064_2F39A7BB X-CRM114-Status: GOOD ( 11.64 ) 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 Wed, May 01, 2024 at 06:32:45PM +0530, Kanchan Joshi wrote: > Can you please tell what function(s) in bio data path that need this > conversion? > To me data path handling seems similar. Each cloned bio will lead to > some amount of data transfer to pinned user-memory. The same is > happening for meta transfer here. Well, everywhere. e.g. for direct I/O everything is just driven from the fs/direct-io.c and and fs/iomap/direct-io.c code without any knowledge in the underlying driver if data has been pinned (no bounce buffering in this case). Or for passthrough I/O none of the underlying logic knows about the pinning or bounce buffering, everything is handled in block/blk-map.c.