From patchwork Fri Dec 18 17:40:09 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergei Miroshnichenko X-Patchwork-Id: 11982681 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3C2D4C4361B for ; Fri, 18 Dec 2020 17:43:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1922723B54 for ; Fri, 18 Dec 2020 17:43:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730270AbgLRRnQ (ORCPT ); Fri, 18 Dec 2020 12:43:16 -0500 Received: from mta-02.yadro.com ([89.207.88.252]:38596 "EHLO mta-01.yadro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727967AbgLRRnQ (ORCPT ); Fri, 18 Dec 2020 12:43:16 -0500 Received: from localhost (unknown [127.0.0.1]) by mta-01.yadro.com (Postfix) with ESMTP id 7409C413D5; Fri, 18 Dec 2020 17:41:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=yadro.com; h= content-type:content-type:content-transfer-encoding:mime-version :references:in-reply-to:x-mailer:message-id:date:date:subject :subject:from:from:received:received:received; s=mta-01; t= 1608313292; x=1610127693; bh=cLgLn4rXA1xiaAB3ENuZEne5ERVt5u32Jus mMyXwWHM=; b=fWEezA475dRWxuKNqbIf1tW5G5lCL3v3YDTS0Qhv27i6xC9Me21 K/0cwxljMltO4inYY1SvxrENm+7iNii2kmawyz3zqOWMoAcNITOQ72okdt6rd1Ut k4jLEgONfLP/KoUk2SX4CGzXGdBf0xIDssIiJZ+08F8Gp/pip7u5gt/g= X-Virus-Scanned: amavisd-new at yadro.com Received: from mta-01.yadro.com ([127.0.0.1]) by localhost (mta-01.yadro.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 7Rbb2F7mdMFZ; Fri, 18 Dec 2020 20:41:32 +0300 (MSK) Received: from T-EXCH-03.corp.yadro.com (t-exch-03.corp.yadro.com [172.17.100.103]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-SHA384 (256/256 bits)) (No client certificate requested) by mta-01.yadro.com (Postfix) with ESMTPS id EB213413E0; Fri, 18 Dec 2020 20:41:10 +0300 (MSK) Received: from NB-148.yadro.com (172.17.15.136) by T-EXCH-03.corp.yadro.com (172.17.100.103) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.32; Fri, 18 Dec 2020 20:41:10 +0300 From: Sergei Miroshnichenko To: CC: Bjorn Helgaas , Lukas Wunner , Stefan Roese , Andy Lavr , =?utf-8?q?Chris?= =?utf-8?q?tian_K=C3=B6nig?= , David Laight , Rajat Jain , , Sergei Miroshnichenko , , Christoph Hellwig Subject: [PATCH v9 24/26] nvme-pci: Handle movable BARs Date: Fri, 18 Dec 2020 20:40:09 +0300 Message-ID: <20201218174011.340514-25-s.miroshnichenko@yadro.com> X-Mailer: git-send-email 2.24.1 In-Reply-To: <20201218174011.340514-1-s.miroshnichenko@yadro.com> References: <20201218174011.340514-1-s.miroshnichenko@yadro.com> MIME-Version: 1.0 X-Originating-IP: [172.17.15.136] X-ClientProxiedBy: T-EXCH-01.corp.yadro.com (172.17.10.101) To T-EXCH-03.corp.yadro.com (172.17.100.103) Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hot-added devices can affect the existing ones by moving their BARs. The PCI subsystem will inform the NVME driver about this by invoking the .rescan_prepare() and .rescan_done() hooks, so the BARs can by re-mapped. Tested under the "randrw" mode of the fio tool, and when using an NVME drive as a root filesystem storage. Before the hot-adding: % sudo cat /proc/iomem ... 3fe800000000-3fe8007fffff : PCI Bus 0020:0b 3fe800000000-3fe8007fffff : PCI Bus 0020:18 3fe800000000-3fe8000fffff : 0020:18:00.0 3fe800000000-3fe8000fffff : nvme ^^^^^^^^^^^^^^^^^^^^^^^^^ 3fe800100000-3fe80017ffff : 0020:18:00.0 ... Then another NVME drive was hot-added, so BARs of the 0020:18:00.0 are moved: % sudo cat /proc/iomem ... 3fe800000000-3fe800ffffff : PCI Bus 0020:0b 3fe800000000-3fe8007fffff : PCI Bus 0020:10 3fe800000000-3fe800003fff : 0020:10:00.0 3fe800000000-3fe800003fff : nvme 3fe800010000-3fe80001ffff : 0020:10:00.0 3fe800800000-3fe800ffffff : PCI Bus 0020:18 3fe800800000-3fe8008fffff : 0020:18:00.0 3fe800800000-3fe8008fffff : nvme ^^^^^^^^^^^^^^^^^^^^^^^^^ 3fe800900000-3fe80097ffff : 0020:18:00.0 ... During the rescanning, both READ and WRITE speeds drop to zero for a while due to driver's pause, then restore. Cc: linux-nvme@lists.infradead.org Cc: Christoph Hellwig Signed-off-by: Sergei Miroshnichenko --- drivers/nvme/host/pci.c | 27 ++++++++++++++++++++++++++- 1 file changed, 26 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index b4385cb0ff60..7993062b11b6 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -1656,7 +1656,7 @@ static int nvme_remap_bar(struct nvme_dev *dev, unsigned long size) { struct pci_dev *pdev = to_pci_dev(dev->dev); - if (size <= dev->bar_mapped_size) + if (dev->bar && size <= dev->bar_mapped_size) return 0; if (size > pci_resource_len(pdev, 0)) return -ENOMEM; @@ -3152,6 +3152,28 @@ static void nvme_error_resume(struct pci_dev *pdev) flush_work(&dev->ctrl.reset_work); } +static bool nvme_bar_fixed(struct pci_dev *pdev, int resno) +{ + return false; +} + +static void nvme_rescan_prepare(struct pci_dev *pdev) +{ + struct nvme_dev *dev = pci_get_drvdata(pdev); + + nvme_dev_disable(dev, true); + nvme_dev_unmap(dev); + dev->bar = NULL; +} + +static void nvme_rescan_done(struct pci_dev *pdev) +{ + struct nvme_dev *dev = pci_get_drvdata(pdev); + + nvme_dev_map(dev); + nvme_reset_ctrl(&dev->ctrl); +} + static const struct pci_error_handlers nvme_err_handler = { .error_detected = nvme_error_detected, .slot_reset = nvme_slot_reset, @@ -3238,6 +3260,9 @@ static struct pci_driver nvme_driver = { #endif .sriov_configure = pci_sriov_configure_simple, .err_handler = &nvme_err_handler, + .rescan_prepare = nvme_rescan_prepare, + .rescan_done = nvme_rescan_done, + .bar_fixed = nvme_bar_fixed, }; static int __init nvme_init(void)