From patchwork Mon Jun 27 15:25:16 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Garry X-Patchwork-Id: 586056 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 07B89C43334 for ; Mon, 27 Jun 2022 15:31:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238276AbiF0Pbn (ORCPT ); Mon, 27 Jun 2022 11:31:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51396 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238187AbiF0Pbg (ORCPT ); Mon, 27 Jun 2022 11:31:36 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2F9619C24; Mon, 27 Jun 2022 08:31:34 -0700 (PDT) Received: from fraeml745-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4LWs6X2L4Gz67VxZ; Mon, 27 Jun 2022 23:27:32 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml745-chm.china.huawei.com (10.206.15.226) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 27 Jun 2022 17:31:32 +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; Mon, 27 Jun 2022 16:31:28 +0100 From: John Garry To: , , , , , , , CC: , , , , , , , John Garry Subject: [PATCH v4 0/5] DMA mapping changes for SCSI core Date: Mon, 27 Jun 2022 23:25:16 +0800 Message-ID: <1656343521-62897-1-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: dggems703-chm.china.huawei.com (10.3.19.180) 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/ [1] https://lore.kernel.org/linux-iommu/f5b78c9c-312e-70ab-ecbb-f14623a4b6e3@arm.com/ 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 Changes since v2: - Rebase on v5.19-rc1 - Add Damien's tag to 2/4 (thanks) Changes since v1: - Relocate scsi_add_host_with_dma() dma_dev check (Reported by Dan) - Add tags from Damien and Martin (thanks) - note: I only added Martin's tag to the SCSI patch John Garry (5): dma-mapping: Add dma_opt_mapping_size() dma-iommu: Add iommu_dma_opt_mapping_size() scsi: core: Cap shost max_sectors according to DMA mapping limits only once scsi: scsi_transport_sas: Cap shost max_sectors according to DMA optimal mapping limit libata-scsi: Cap ata_device->max_sectors according to shost->max_sectors Documentation/core-api/dma-api.rst | 9 +++++++++ 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 ++++++ include/linux/dma-map-ops.h | 1 + include/linux/dma-mapping.h | 5 +++++ include/linux/iova.h | 2 ++ kernel/dma/mapping.c | 12 ++++++++++++ 11 files changed, 52 insertions(+), 4 deletions(-)