From nobody Sat Apr 18 10:53:36 2026 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 DD495CCA47B for ; Thu, 14 Jul 2022 11:22:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238637AbiGNLWX (ORCPT ); Thu, 14 Jul 2022 07:22:23 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58264 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238457AbiGNLWS (ORCPT ); Thu, 14 Jul 2022 07:22:18 -0400 Received: from sinmsgout01.his.huawei.com (sinmsgout01.his.huawei.com [119.8.177.36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ABE874F642; Thu, 14 Jul 2022 04:22:15 -0700 (PDT) Received: from fraeml741-chm.china.huawei.com (unknown [172.18.156.147]) by sinmsgout01.his.huawei.com (SkyGuard) with ESMTP id 4LkBlx5H7xz9ttCk; Thu, 14 Jul 2022 19:17:17 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml741-chm.china.huawei.com (10.206.15.222) 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 13:22:07 +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 12:22:03 +0100 From: John Garry To: , , , , , , , CC: , , , , , , John Garry Subject: [PATCH v6 1/6] dma-mapping: Add dma_opt_mapping_size() Date: Thu, 14 Jul 2022 19:15:24 +0800 Message-ID: <1657797329-98541-2-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1657797329-98541-1-git-send-email-john.garry@huawei.com> References: <1657797329-98541-1-git-send-email-john.garry@huawei.com> 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-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Streaming DMA mapping involving an IOMMU may be much slower for larger total mapping size. This is because every IOMMU DMA mapping requires an IOVA to be allocated and freed. IOVA sizes above a certain limit are not cached, which can have a big impact on DMA mapping performance. Provide an API for device drivers to know this "optimal" limit, such that they may try to produce mapping which don't exceed it. Signed-off-by: John Garry Reviewed-by: Damien Le Moal Acked-by: Martin K. Petersen --- Documentation/core-api/dma-api.rst | 14 ++++++++++++++ include/linux/dma-map-ops.h | 1 + include/linux/dma-mapping.h | 5 +++++ kernel/dma/mapping.c | 12 ++++++++++++ 4 files changed, 32 insertions(+) diff --git a/Documentation/core-api/dma-api.rst b/Documentation/core-api/dm= a-api.rst index 6d6d0edd2d27..829f20a193ca 100644 --- a/Documentation/core-api/dma-api.rst +++ b/Documentation/core-api/dma-api.rst @@ -204,6 +204,20 @@ Returns the maximum size of a mapping for the device. = The size parameter of the mapping functions like dma_map_single(), dma_map_page() and others should not be larger than the returned value. =20 +:: + + size_t + dma_opt_mapping_size(struct device *dev); + +Returns the maximum optimal size of a mapping for the device. + +Mapping larger buffers may take much longer in certain scenarios. In +addition, for high-rate short-lived streaming mappings, the upfront time +spent on the mapping may account for an appreciable part of the total +request lifetime. As such, if splitting larger requests incurs no +significant performance penalty, then device drivers are advised to +limit total DMA streaming mappings length to the returned value. + :: =20 bool diff --git a/include/linux/dma-map-ops.h b/include/linux/dma-map-ops.h index 0d5b06b3a4a6..98ceba6fa848 100644 --- a/include/linux/dma-map-ops.h +++ b/include/linux/dma-map-ops.h @@ -69,6 +69,7 @@ struct dma_map_ops { int (*dma_supported)(struct device *dev, u64 mask); u64 (*get_required_mask)(struct device *dev); size_t (*max_mapping_size)(struct device *dev); + size_t (*opt_mapping_size)(void); unsigned long (*get_merge_boundary)(struct device *dev); }; =20 diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h index dca2b1355bb1..fe3849434b2a 100644 --- a/include/linux/dma-mapping.h +++ b/include/linux/dma-mapping.h @@ -144,6 +144,7 @@ int dma_set_mask(struct device *dev, u64 mask); int dma_set_coherent_mask(struct device *dev, u64 mask); u64 dma_get_required_mask(struct device *dev); size_t dma_max_mapping_size(struct device *dev); +size_t dma_opt_mapping_size(struct device *dev); bool dma_need_sync(struct device *dev, dma_addr_t dma_addr); unsigned long dma_get_merge_boundary(struct device *dev); struct sg_table *dma_alloc_noncontiguous(struct device *dev, size_t size, @@ -266,6 +267,10 @@ static inline size_t dma_max_mapping_size(struct devic= e *dev) { return 0; } +static inline size_t dma_opt_mapping_size(struct device *dev) +{ + return 0; +} static inline bool dma_need_sync(struct device *dev, dma_addr_t dma_addr) { return false; diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c index db7244291b74..1bfe11b1edb6 100644 --- a/kernel/dma/mapping.c +++ b/kernel/dma/mapping.c @@ -773,6 +773,18 @@ size_t dma_max_mapping_size(struct device *dev) } EXPORT_SYMBOL_GPL(dma_max_mapping_size); =20 +size_t dma_opt_mapping_size(struct device *dev) +{ + const struct dma_map_ops *ops =3D get_dma_ops(dev); + size_t size =3D SIZE_MAX; + + if (ops && ops->opt_mapping_size) + size =3D ops->opt_mapping_size(); + + return min(dma_max_mapping_size(dev), size); +} +EXPORT_SYMBOL_GPL(dma_opt_mapping_size); + bool dma_need_sync(struct device *dev, dma_addr_t dma_addr) { const struct dma_map_ops *ops =3D get_dma_ops(dev); --=20 2.35.3 From nobody Sat Apr 18 10:53:36 2026 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 8582BC43334 for ; Thu, 14 Jul 2022 11:22:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238660AbiGNLW1 (ORCPT ); Thu, 14 Jul 2022 07:22:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58308 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238462AbiGNLWT (ORCPT ); Thu, 14 Jul 2022 07:22:19 -0400 Received: from sinmsgout01.his.huawei.com (sinmsgout01.his.huawei.com [119.8.177.36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 78499558CF; Thu, 14 Jul 2022 04:22:18 -0700 (PDT) Received: from fraeml739-chm.china.huawei.com (unknown [172.18.156.207]) by sinmsgout01.his.huawei.com (SkyGuard) with ESMTP id 4LkBm13vF2z9v7Hd; Thu, 14 Jul 2022 19:17:21 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml739-chm.china.huawei.com (10.206.15.220) 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 13:22:11 +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 12:22:07 +0100 From: John Garry To: , , , , , , , CC: , , , , , , John Garry Subject: [PATCH v6 2/6] dma-iommu: Add iommu_dma_opt_mapping_size() Date: Thu, 14 Jul 2022 19:15:25 +0800 Message-ID: <1657797329-98541-3-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1657797329-98541-1-git-send-email-john.garry@huawei.com> References: <1657797329-98541-1-git-send-email-john.garry@huawei.com> 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-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Add the IOMMU callback for DMA mapping API dma_opt_mapping_size(), which allows the drivers to know the optimal mapping limit and thus limit the requested IOVA lengths. This value is based on the IOVA rcache range limit, as IOVAs allocated above this limit must always be newly allocated, which may be quite slow. Signed-off-by: John Garry Reviewed-by: Damien Le Moal Acked-by: Robin Murphy Acked-by: Martin K. Petersen --- drivers/iommu/dma-iommu.c | 6 ++++++ drivers/iommu/iova.c | 5 +++++ include/linux/iova.h | 2 ++ 3 files changed, 13 insertions(+) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index f90251572a5d..9e1586447ee8 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -1459,6 +1459,11 @@ static unsigned long iommu_dma_get_merge_boundary(st= ruct device *dev) return (1UL << __ffs(domain->pgsize_bitmap)) - 1; } =20 +static size_t iommu_dma_opt_mapping_size(void) +{ + return iova_rcache_range(); +} + static const struct dma_map_ops iommu_dma_ops =3D { .alloc =3D iommu_dma_alloc, .free =3D iommu_dma_free, @@ -1479,6 +1484,7 @@ static const struct dma_map_ops iommu_dma_ops =3D { .map_resource =3D iommu_dma_map_resource, .unmap_resource =3D iommu_dma_unmap_resource, .get_merge_boundary =3D iommu_dma_get_merge_boundary, + .opt_mapping_size =3D iommu_dma_opt_mapping_size, }; =20 /* diff --git a/drivers/iommu/iova.c b/drivers/iommu/iova.c index db77aa675145..9f00b58d546e 100644 --- a/drivers/iommu/iova.c +++ b/drivers/iommu/iova.c @@ -26,6 +26,11 @@ static unsigned long iova_rcache_get(struct iova_domain = *iovad, static void free_cpu_cached_iovas(unsigned int cpu, struct iova_domain *io= vad); static void free_iova_rcaches(struct iova_domain *iovad); =20 +unsigned long iova_rcache_range(void) +{ + return PAGE_SIZE << (IOVA_RANGE_CACHE_MAX_SIZE - 1); +} + static int iova_cpuhp_dead(unsigned int cpu, struct hlist_node *node) { struct iova_domain *iovad; diff --git a/include/linux/iova.h b/include/linux/iova.h index 320a70e40233..c6ba6d95d79c 100644 --- a/include/linux/iova.h +++ b/include/linux/iova.h @@ -79,6 +79,8 @@ static inline unsigned long iova_pfn(struct iova_domain *= iovad, dma_addr_t iova) int iova_cache_get(void); void iova_cache_put(void); =20 +unsigned long iova_rcache_range(void); + void free_iova(struct iova_domain *iovad, unsigned long pfn); void __free_iova(struct iova_domain *iovad, struct iova *iova); struct iova *alloc_iova(struct iova_domain *iovad, unsigned long size, --=20 2.35.3 From nobody Sat Apr 18 10:53:36 2026 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 96D15CCA480 for ; Thu, 14 Jul 2022 11:22:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238674AbiGNLWg (ORCPT ); Thu, 14 Jul 2022 07:22:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58380 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238636AbiGNLWX (ORCPT ); Thu, 14 Jul 2022 07:22:23 -0400 Received: from sinmsgout03.his.huawei.com (sinmsgout03.his.huawei.com [119.8.177.38]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E7318558FA; Thu, 14 Jul 2022 04:22:20 -0700 (PDT) Received: from fraeml740-chm.china.huawei.com (unknown [172.18.156.148]) by sinmsgout03.his.huawei.com (SkyGuard) with ESMTP id 4LkBrQ6KWpz9v7Bs; Thu, 14 Jul 2022 19:21:10 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml740-chm.china.huawei.com (10.206.15.221) 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 13:22:15 +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 12:22:11 +0100 From: John Garry To: , , , , , , , CC: , , , , , , John Garry Subject: [PATCH v6 3/6] scsi: core: Cap shost max_sectors according to DMA limits only once Date: Thu, 14 Jul 2022 19:15:26 +0800 Message-ID: <1657797329-98541-4-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1657797329-98541-1-git-send-email-john.garry@huawei.com> References: <1657797329-98541-1-git-send-email-john.garry@huawei.com> 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-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" The shost->max_sectors is repeatedly capped according to the host DMA mapping limit for each sdev in __scsi_init_queue(). This is unnecessary, so set only once when adding the host. Signed-off-by: John Garry Reviewed-by: Damien Le Moal Acked-by: Martin K. Petersen --- drivers/scsi/hosts.c | 5 +++++ drivers/scsi/scsi_lib.c | 4 ---- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c index 8352f90d997d..d04bd2c7c9f1 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -236,6 +236,11 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, st= ruct device *dev, =20 shost->dma_dev =3D dma_dev; =20 + if (dma_dev->dma_mask) { + shost->max_sectors =3D min_t(unsigned int, shost->max_sectors, + dma_max_mapping_size(dma_dev) >> SECTOR_SHIFT); + } + error =3D scsi_mq_setup_tags(shost); if (error) goto fail; diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 6ffc9e4258a8..6ce8acea322a 100644 --- a/drivers/scsi/scsi_lib.c +++ b/drivers/scsi/scsi_lib.c @@ -1884,10 +1884,6 @@ void __scsi_init_queue(struct Scsi_Host *shost, stru= ct request_queue *q) blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); } =20 - if (dev->dma_mask) { - shost->max_sectors =3D min_t(unsigned int, shost->max_sectors, - dma_max_mapping_size(dev) >> SECTOR_SHIFT); - } blk_queue_max_hw_sectors(q, shost->max_sectors); blk_queue_segment_boundary(q, shost->dma_boundary); dma_set_seg_boundary(dev, shost->dma_boundary); --=20 2.35.3 From nobody Sat Apr 18 10:53:36 2026 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 8D2A0C433EF for ; Thu, 14 Jul 2022 11:23:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238703AbiGNLXB (ORCPT ); Thu, 14 Jul 2022 07:23:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58510 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238676AbiGNLWr (ORCPT ); Thu, 14 Jul 2022 07:22:47 -0400 Received: from sinmsgout03.his.huawei.com (sinmsgout03.his.huawei.com [119.8.177.38]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 596DF5723C; Thu, 14 Jul 2022 04:22:31 -0700 (PDT) Received: from fraeml738-chm.china.huawei.com (unknown [172.18.156.208]) by sinmsgout03.his.huawei.com (SkyGuard) with ESMTP id 4LkBrV5CLvz9xGPv; Thu, 14 Jul 2022 19:21:14 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml738-chm.china.huawei.com (10.206.15.219) 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 13:22:18 +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 12:22:14 +0100 From: John Garry To: , , , , , , , CC: , , , , , , John Garry Subject: [PATCH v6 4/6] scsi: sd: Allow max_sectors be capped at DMA optimal size limit Date: Thu, 14 Jul 2022 19:15:27 +0800 Message-ID: <1657797329-98541-5-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1657797329-98541-1-git-send-email-john.garry@huawei.com> References: <1657797329-98541-1-git-send-email-john.garry@huawei.com> 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-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Streaming DMA mappings may be considerably slower when mappings go through an IOMMU and the total mapping length is somewhat long. This is because the IOMMU IOVA code allocates and free an IOVA for each mapping, which may affect performance. New member Scsi_Host.opt_sectors is added, which is the optimal host max_sectors, and use this value to cap the request queue max_sectors when set. It could be considered to have request queues io_opt value initially set at Scsi_Host.opt_sectors in __scsi_init_queue(), but that is not really the purpose of io_opt. Finally, even though Scsi_Host.opt_sectors value should never be greater than the request queue max_hw_sectors value, continue to limit to this value for safety. Signed-off-by: John Garry Acked-by: Martin K. Petersen Reviewed-by: Damien Le Moal --- drivers/scsi/sd.c | 2 ++ include/scsi/scsi_host.h | 1 + 2 files changed, 3 insertions(+) diff --git a/drivers/scsi/sd.c b/drivers/scsi/sd.c index a1a2ac09066f..3eaee1f7aaca 100644 --- a/drivers/scsi/sd.c +++ b/drivers/scsi/sd.c @@ -3296,6 +3296,8 @@ static int sd_revalidate_disk(struct gendisk *disk) (sector_t)BLK_DEF_MAX_SECTORS); } =20 + rw_max =3D min_not_zero(rw_max, sdp->host->opt_sectors); + /* Do not exceed controller limit */ rw_max =3D min(rw_max, queue_max_hw_sectors(q)); =20 diff --git a/include/scsi/scsi_host.h b/include/scsi/scsi_host.h index 667d889b92b5..d32a84b2bb40 100644 --- a/include/scsi/scsi_host.h +++ b/include/scsi/scsi_host.h @@ -607,6 +607,7 @@ struct Scsi_Host { short unsigned int sg_tablesize; short unsigned int sg_prot_tablesize; unsigned int max_sectors; + unsigned int opt_sectors; unsigned int max_segment_size; unsigned long dma_boundary; unsigned long virt_boundary_mask; --=20 2.35.3 From nobody Sat Apr 18 10:53:36 2026 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 57B67C433EF for ; Thu, 14 Jul 2022 11:23:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238736AbiGNLW7 (ORCPT ); Thu, 14 Jul 2022 07:22:59 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238662AbiGNLWi (ORCPT ); Thu, 14 Jul 2022 07:22:38 -0400 Received: from sinmsgout01.his.huawei.com (sinmsgout01.his.huawei.com [119.8.177.36]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A1E55722C; Thu, 14 Jul 2022 04:22:29 -0700 (PDT) Received: from fraeml737-chm.china.huawei.com (unknown [172.18.156.147]) by sinmsgout01.his.huawei.com (SkyGuard) with ESMTP id 4LkBmF04bvz9v7J8; Thu, 14 Jul 2022 19:17:32 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml737-chm.china.huawei.com (10.206.15.218) 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 13:22:22 +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 12:22:18 +0100 From: John Garry To: , , , , , , , CC: , , , , , , John Garry Subject: [PATCH v6 5/6] scsi: scsi_transport_sas: Cap shost opt_sectors according to DMA optimal limit Date: Thu, 14 Jul 2022 19:15:28 +0800 Message-ID: <1657797329-98541-6-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1657797329-98541-1-git-send-email-john.garry@huawei.com> References: <1657797329-98541-1-git-send-email-john.garry@huawei.com> 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-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" Streaming DMA mappings may be considerably slower when mappings go through an IOMMU and the total mapping length is somewhat long. This is because the IOMMU IOVA code allocates and free an IOVA for each mapping, which may affect performance. For performance reasons set the request queue max_sectors from dma_opt_mapping_size(), which knows this mapping limit. Signed-off-by: John Garry Reviewed-by: Damien Le Moal --- drivers/scsi/scsi_transport_sas.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/drivers/scsi/scsi_transport_sas.c b/drivers/scsi/scsi_transpor= t_sas.c index 12bff64dade6..2f88c61216ee 100644 --- a/drivers/scsi/scsi_transport_sas.c +++ b/drivers/scsi/scsi_transport_sas.c @@ -225,6 +225,7 @@ static int sas_host_setup(struct transport_container *t= c, struct device *dev, { struct Scsi_Host *shost =3D dev_to_shost(dev); struct sas_host_attrs *sas_host =3D to_sas_host_attrs(shost); + struct device *dma_dev =3D shost->dma_dev; =20 INIT_LIST_HEAD(&sas_host->rphy_list); mutex_init(&sas_host->lock); @@ -236,6 +237,11 @@ static int sas_host_setup(struct transport_container *= tc, struct device *dev, dev_printk(KERN_ERR, dev, "fail to a bsg device %d\n", shost->host_no); =20 + if (dma_dev->dma_mask) { + shost->opt_sectors =3D min_t(unsigned int, shost->max_sectors, + dma_opt_mapping_size(dma_dev) >> SECTOR_SHIFT); + } + return 0; } =20 --=20 2.35.3 From nobody Sat Apr 18 10:53:36 2026 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 1F2D0C433EF for ; Thu, 14 Jul 2022 11:23:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238761AbiGNLXE (ORCPT ); Thu, 14 Jul 2022 07:23:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59102 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238677AbiGNLWr (ORCPT ); Thu, 14 Jul 2022 07:22:47 -0400 Received: from sinmsgout03.his.huawei.com (sinmsgout03.his.huawei.com [119.8.177.38]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 59A4157E09; Thu, 14 Jul 2022 04:22:32 -0700 (PDT) Received: from fraeml735-chm.china.huawei.com (unknown [172.18.156.148]) by sinmsgout03.his.huawei.com (SkyGuard) with ESMTP id 4LkBrf1MBCz9xGQ7; Thu, 14 Jul 2022 19:21:22 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml735-chm.china.huawei.com (10.206.15.216) 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 13:22:26 +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 12:22:22 +0100 From: John Garry To: , , , , , , , CC: , , , , , , John Garry Subject: [PATCH v6 6/6] ata: libata-scsi: Cap ata_device->max_sectors according to shost->max_sectors Date: Thu, 14 Jul 2022 19:15:29 +0800 Message-ID: <1657797329-98541-7-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1657797329-98541-1-git-send-email-john.garry@huawei.com> References: <1657797329-98541-1-git-send-email-john.garry@huawei.com> 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-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" ATA devices (struct ata_device) have a max_sectors field which is configured internally in libata. This is then used to (re)configure the associated sdev request queue max_sectors value from how it is earlier set in __scsi_init_queue(). In __scsi_init_queue() the max_sectors value is set according to shost limits, which includes host DMA mapping limits. Cap the ata_device max_sectors according to shost->max_sectors to respect this shost limit. Signed-off-by: John Garry Acked-by: Damien Le Moal Acked-by: Martin K. Petersen --- drivers/ata/libata-scsi.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c index 86dbb1cdfabd..24a43d540d9f 100644 --- a/drivers/ata/libata-scsi.c +++ b/drivers/ata/libata-scsi.c @@ -1060,6 +1060,7 @@ int ata_scsi_dev_config(struct scsi_device *sdev, str= uct ata_device *dev) dev->flags |=3D ATA_DFLAG_NO_UNLOAD; =20 /* configure max sectors */ + dev->max_sectors =3D min(dev->max_sectors, sdev->host->max_sectors); blk_queue_max_hw_sectors(q, dev->max_sectors); =20 if (dev->class =3D=3D ATA_DEV_ATAPI) { --=20 2.35.3