From patchwork Mon Jun 6 09:30:21 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: John Garry X-Patchwork-Id: 12870181 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 3423CC433EF for ; Mon, 6 Jun 2022 09:37:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232957AbiFFJhG (ORCPT ); Mon, 6 Jun 2022 05:37:06 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47022 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232949AbiFFJgr (ORCPT ); Mon, 6 Jun 2022 05:36:47 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7E8711BF80F; Mon, 6 Jun 2022 02:36:45 -0700 (PDT) Received: from fraeml744-chm.china.huawei.com (unknown [172.18.147.201]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4LGpFQ1FFVz684JT; Mon, 6 Jun 2022 17:33:14 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml744-chm.china.huawei.com (10.206.15.225) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 6 Jun 2022 11:36:43 +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, 6 Jun 2022 10:36:39 +0100 From: John Garry To: , , , , , , , CC: , , , , , , , , John Garry Subject: [PATCH v3 3/4] scsi: core: Cap shost max_sectors according to DMA optimum mapping limits Date: Mon, 6 Jun 2022 17:30:21 +0800 Message-ID: <1654507822-168026-4-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1654507822-168026-1-git-send-email-john.garry@huawei.com> References: <1654507822-168026-1-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-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 8352f90d997d..ea1a207634d1 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, 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); + } + error = 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, 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);