From patchwork Thu Jul 14 11:15:23 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Garry X-Patchwork-Id: 591615 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 430CFC433EF for ; Thu, 14 Jul 2022 11:22:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238529AbiGNLWW (ORCPT ); Thu, 14 Jul 2022 07:22:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58320 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238492AbiGNLWU (ORCPT ); Thu, 14 Jul 2022 07:22:20 -0400 Received: from sinsgout.his.huawei.com (sinsgout.his.huawei.com [119.8.179.247]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7D48E481DE; Thu, 14 Jul 2022 04:22:17 -0700 (PDT) Received: from sinmsgout03.his.huawei.com (unknown [172.28.115.130]) by sinsgout.his.huawei.com (SkyGuard) with ESMTP id 4LkBsd2QvSz5Rsyp; Thu, 14 Jul 2022 19:22:13 +0800 (CST) Received: from fraeml742-chm.china.huawei.com (unknown [172.18.156.207]) by sinmsgout03.his.huawei.com (SkyGuard) with ESMTP id 4LkBrC1b2Lz9v7Bs; Thu, 14 Jul 2022 19:20:59 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml742-chm.china.huawei.com (10.206.15.223) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 14 Jul 2022 13:22:03 +0200 Received: from localhost.localdomain (10.69.192.58) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Thu, 14 Jul 2022 12:21:59 +0100 From: John Garry To: , , , , , , , CC: , , , , , , John Garry Subject: [PATCH v6 0/6] DMA mapping changes for SCSI core Date: Thu, 14 Jul 2022 19:15:23 +0800 Message-ID: <1657797329-98541-1-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 MIME-Version: 1.0 X-Originating-IP: [10.69.192.58] X-ClientProxiedBy: dggems705-chm.china.huawei.com (10.3.19.182) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-scsi@vger.kernel.org As reported in [0], DMA mappings whose size exceeds the IOMMU IOVA caching limit may see a big performance hit. This series introduces a new DMA mapping API, dma_opt_mapping_size(), so that drivers may know this limit when performance is a factor in the mapping. The SCSI SAS transport code is modified only to use this limit. For now I did not want to touch other hosts as I have a concern that this change could cause a performance regression. I also added a patch for libata-scsi as it does not currently honour the shost max_sectors limit. [0] https://lore.kernel.org/linux-iommu/20210129092120.1482-1-thunder.leizhen@huawei.com/ Changes since v5: - Rebase to Linux 5.19-rc6 - Add Martin's tags to unmodified patches (thanks!) - Apply DMA opt limit to max_sectors in sd driver, and not max_hw_sectors Changes since v4: - tweak libata and other patch titles - Add Robin's tag (thanks!) - Clarify description of new DMA mapping API Changes since v3: - Apply max DMA optimial limit to SAS hosts only Note: Even though "scsi: core: Cap shost max_sectors only once when adding" is a subset of a previous patch I did not transfer the RB tags - Rebase on v5.19-rc4 John Garry (6): dma-mapping: Add dma_opt_mapping_size() dma-iommu: Add iommu_dma_opt_mapping_size() scsi: core: Cap shost max_sectors according to DMA limits only once scsi: sd: Allow max_sectors be capped at DMA optimal size limit scsi: scsi_transport_sas: Cap shost opt_sectors according to DMA optimal limit ata: libata-scsi: Cap ata_device->max_sectors according to shost->max_sectors Documentation/core-api/dma-api.rst | 14 ++++++++++++++ drivers/ata/libata-scsi.c | 1 + drivers/iommu/dma-iommu.c | 6 ++++++ drivers/iommu/iova.c | 5 +++++ drivers/scsi/hosts.c | 5 +++++ drivers/scsi/scsi_lib.c | 4 ---- drivers/scsi/scsi_transport_sas.c | 6 ++++++ drivers/scsi/sd.c | 2 ++ include/linux/dma-map-ops.h | 1 + include/linux/dma-mapping.h | 5 +++++ include/linux/iova.h | 2 ++ include/scsi/scsi_host.h | 1 + kernel/dma/mapping.c | 12 ++++++++++++ 13 files changed, 60 insertions(+), 4 deletions(-)