From patchwork Thu Oct 19 15:25:31 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chuck Lever X-Patchwork-Id: 13429369 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 35DCDCDB482 for ; Thu, 19 Oct 2023 15:25:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1345450AbjJSPZf (ORCPT ); Thu, 19 Oct 2023 11:25:35 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44692 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345550AbjJSPZf (ORCPT ); Thu, 19 Oct 2023 11:25:35 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E52E3121 for ; Thu, 19 Oct 2023 08:25:33 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id B5754C433C7; Thu, 19 Oct 2023 15:25:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1697729133; bh=u/lMWJ+F7E/hlh7pbvNFzd6HWcLB+2i2s6p2bJhsGNM=; h=Subject:From:Cc:Date:From; b=s/A5u5nuYoWGo2aupBwIYcocCx0oznUJzPAn7aPczoF6P6tSHzITH5v2c6K7hAVmx GhmTRWBYv+D/AwH5OX2rDNeHaI802fKR9+OHWUh7LMofQKaIMbOeNuJKOyRmGxi3YS E031nLW9QIJpzOZmLdi8u3jVoU1Zr5pEeGkvKR1ElUgTG6d6ABKDb6Kpb5zUaxu0Gv cetfm0rfcQgArFAzt8rtEatpFxYgzUw0G+g3AByGweBtac3m4XLQWcjM5gGMVbXs41 fcUJZ6sY6ouUxZUIH8+gkDEr9c3e+Un53EG1ew/0Rv0AJrUzyfmBbsRJYdqnqvjlVq VK0KEJhBcHYWQ== Subject: [PATCH RFC 0/9] Exploring biovec support in (R)DMA API From: Chuck Lever Cc: Marek Szyprowski , Chuck Lever , Robin Murphy , Alexander Potapenko , linux-mm@kvack.org, linux-rdma@vger.kernel.org, Jens Axboe , kasan-dev@googlegroups.com, David Howells , iommu@lists.linux.dev, Christoph Hellwig Date: Thu, 19 Oct 2023 11:25:31 -0400 Message-ID: <169772852492.5232.17148564580779995849.stgit@klimt.1015granger.net> User-Agent: StGit/1.5 MIME-Version: 1.0 To: unlisted-recipients:; (no To-header on input) Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org The SunRPC stack manages pages (and eventually, folios) via an array of struct biovec items within struct xdr_buf. We have not fully committed to replacing the struct page array in xdr_buf because, although the socket API supports biovec arrays, the RDMA stack uses struct scatterlist rather than struct biovec. This (incomplete) series explores what it might look like if the RDMA core API could support struct biovec array arguments. The series compiles on x86, but I haven't tested it further. I'm posting early in hopes of starting further discussion. Are there other upper layer API consumers, besides SunRPC, who might prefer the use of biovec over scatterlist? Besides handling folios as well as single pages in bv_page, what other work might be needed in the DMA layer? What RDMA core APIs should be converted? IMO a DMA mapping and registration API for biovecs would be needed. Maybe RDMA Read and Write too? --- Chuck Lever (9): dma-debug: Fix a typo in a debugging eye-catcher bvec: Add bio_vec fields to manage DMA mapping dma-debug: Add dma_debug_ helpers for mapping bio_vec arrays mm: kmsan: Add support for DMA mapping bio_vec arrays dma-direct: Support direct mapping bio_vec arrays DMA-API: Add dma_sync_bvecs_for_cpu() and dma_sync_bvecs_for_device() DMA: Add dma_map_bvecs_attrs() iommu/dma: Support DMA-mapping a bio_vec array RDMA: Add helpers for DMA-mapping an array of bio_vecs drivers/iommu/dma-iommu.c | 368 ++++++++++++++++++++++++++++++++++++ drivers/iommu/iommu.c | 58 ++++++ include/linux/bvec.h | 143 ++++++++++++++ include/linux/dma-map-ops.h | 8 + include/linux/dma-mapping.h | 9 + include/linux/iommu.h | 4 + include/linux/kmsan.h | 20 ++ include/rdma/ib_verbs.h | 29 +++ kernel/dma/debug.c | 165 +++++++++++++++- kernel/dma/debug.h | 38 ++++ kernel/dma/direct.c | 92 +++++++++ kernel/dma/direct.h | 17 ++ kernel/dma/mapping.c | 93 +++++++++ mm/kmsan/hooks.c | 13 ++ 14 files changed, 1056 insertions(+), 1 deletion(-) -- Chuck Lever