From patchwork Thu May 26 10:28:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Garry X-Patchwork-Id: 576440 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 0AF61C433FE for ; Thu, 26 May 2022 10:36:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347076AbiEZKgL (ORCPT ); Thu, 26 May 2022 06:36:11 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55272 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1345407AbiEZKgJ (ORCPT ); Thu, 26 May 2022 06:36:09 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1F9BDCEB82; Thu, 26 May 2022 03:35:54 -0700 (PDT) Received: from fraeml742-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4L843z6jdgz6GDBN; Thu, 26 May 2022 18:31:43 +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, 26 May 2022 12:35:52 +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, 26 May 2022 11:35:47 +0100 From: John Garry To: , , , , , , , CC: , , , , , , , , John Garry Subject: [PATCH v2 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits Date: Thu, 26 May 2022 18:28:33 +0800 Message-ID: <1653560914-82185-4-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1653560914-82185-1-git-send-email-john.garry@huawei.com> References: <1653560914-82185-1-git-send-email-john.garry@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.69.192.58] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) 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 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. In addition, the shost->max_sectors is repeatedly set for each sdev in __scsi_init_queue(). This is unnecessary, so set once when adding the host. Signed-off-by: John Garry Reviewed-by: Damien Le Moal Reviewed-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 f69b77cbf538..9563c0ac567a 100644 --- a/drivers/scsi/hosts.c +++ b/drivers/scsi/hosts.c @@ -240,6 +240,11 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev, shost->dma_dev = dma_dev; + if (dma_dev->dma_mask) { + shost->max_sectors = min_t(unsigned int, shost->max_sectors, + dma_opt_mapping_size(dma_dev) >> SECTOR_SHIFT); + } + /* * Increase usage count temporarily here so that calling * scsi_autopm_put_host() will trigger runtime idle if there is diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c index 8d18cc7e510e..2d43bb8799bd 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, struct request_queue *q) blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); } - if (dev->dma_mask) { - shost->max_sectors = 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);