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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 121F5C30658 for ; Fri, 5 Jul 2024 05:58:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 812EB6B0082; Fri, 5 Jul 2024 01:58:15 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 7C2EA6B0096; Fri, 5 Jul 2024 01:58:15 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6B16F6B0099; Fri, 5 Jul 2024 01:58:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 4D2A26B0082 for ; Fri, 5 Jul 2024 01:58:15 -0400 (EDT) Received: from smtpin21.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay01.hostedemail.com (Postfix) with ESMTP id F02431C08C7 for ; 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d=hostedemail.com; t=1720159067; a=rsa-sha256; cv=none; b=8YpO4Xw86Z5tLZoNGUlGTf0PE2Aj2tlB2cScf7rj7kaKxSyewhoSfhAvQnkrzxJYxsguXs Qxa8JJZW3V5ygdT1ANqw9bIFk4S9+h1fSRdaODbWyf6KXGA7xTz+/aZSAo/RYYt6MVEXqT N7jPpVHYiAe6pDCI9Bj7jipfBaLu28w= ARC-Authentication-Results: i=1; imf08.hostedemail.com; dkim=none; spf=pass (imf08.hostedemail.com: domain of hch@lst.de designates 213.95.11.211 as permitted sender) smtp.mailfrom=hch@lst.de; dmarc=none Received: by verein.lst.de (Postfix, from userid 2407) id D8AEF68AA6; Fri, 5 Jul 2024 07:58:06 +0200 (CEST) Date: Fri, 5 Jul 2024 07:58:06 +0200 From: Christoph Hellwig To: Leon Romanovsky Cc: Robin Murphy , Jens Axboe , Jason Gunthorpe , Joerg Roedel , Will Deacon , Keith Busch , Christoph Hellwig , "Zeng, Oak" , Chaitanya Kulkarni , Sagi Grimberg , Bjorn Helgaas , Logan Gunthorpe , Yishai Hadas , Shameer Kolothum , Kevin Tian , Alex Williamson , Marek Szyprowski , =?iso-8859-1?B?Suly9G1l?= Glisse , Andrew Morton , linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, iommu@lists.linux.dev, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, kvm@vger.kernel.org, linux-mm@kvack.org Subject: Re: [RFC PATCH v1 18/18] nvme-pci: use new dma API Message-ID: <20240705055806.GA11885@lst.de> References: <47eb0510b0a6aa52d9f5665d75fa7093dd6af53f.1719909395.git.leon@kernel.org> <249ec228-4ffd-4121-bd51-f4a19275fee1@arm.com> <20240704171602.GE95824@unreal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240704171602.GE95824@unreal> User-Agent: Mutt/1.5.17 (2007-11-01) X-Stat-Signature: bh63ghh8hdtm9j77jusm9ou6nda96rex X-Rspamd-Queue-Id: 0EEA1160013 X-Rspam-User: X-Rspamd-Server: rspam08 X-HE-Tag: 1720159092-499233 X-HE-Meta: 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 QBhBt9VD uZlWgOC1+6fZ6oIiB5r0VBKkcz2VunNnVRidt+fRDpcMeGJEu4F7sXiNs35LHQzo0i6VbHH6VbY4yHE8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: > This is exactly how dma_map_sg() works. Which dma_map_sg? swiotlb handling is implemented in the underlying ops, dma-direct and dma-iommu specifically. dma-direct just iterates over the entries and calls dma_direct_map_page, which does a per-entry decision to bounce based on is_swiotlb_force_bounce, dma_capable and dma_kmalloc_needs_bounce.