From patchwork Fri Aug 16 16:50:59 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Sergei Miroshnichenko X-Patchwork-Id: 1148353 X-Patchwork-Delegate: bhelgaas@google.com Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=linux-pci-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=yadro.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=yadro.com header.i=@yadro.com header.b="DE2kQ8gz"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 4698V669Mqz9sML for ; Sat, 17 Aug 2019 02:51:26 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727302AbfHPQvZ (ORCPT ); Fri, 16 Aug 2019 12:51:25 -0400 Received: from mta-02.yadro.com ([89.207.88.252]:51484 "EHLO mta-01.yadro.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1727067AbfHPQvY (ORCPT ); Fri, 16 Aug 2019 12:51:24 -0400 Received: from localhost (unknown [127.0.0.1]) by mta-01.yadro.com (Postfix) with ESMTP id 5298742F04; Fri, 16 Aug 2019 16:51:22 +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= 1565974281; x=1567788682; bh=Wvr/G5+MCulC+fzeKgzpPc5JueFBdqSVqZ/ r8VC32lw=; b=DE2kQ8gzLAqhowh2HemKFf/A2xmFpKpjxsAlinl7UjemCfPuIRq pG8bHWEdYBcxD+WHnhrEMlIZuqV5/QSVbgQQavMH6PeqXMAOtl5H8U4a1TcpmnDL E/NxJ8FcNoCau5OZyie/t71V1c6ipEFwuGeyb5CRXbkI9fznSkbnQihk= 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 PKREUo0eCtq5; Fri, 16 Aug 2019 19:51:21 +0300 (MSK) Received: from T-EXCH-02.corp.yadro.com (t-exch-02.corp.yadro.com [172.17.10.102]) (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 8D1FA42EEC; Fri, 16 Aug 2019 19:51:13 +0300 (MSK) Received: from NB-148.yadro.com (172.17.15.60) by T-EXCH-02.corp.yadro.com (172.17.10.102) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384_P384) id 15.1.669.32; Fri, 16 Aug 2019 19:51:13 +0300 From: Sergey Miroshnichenko To: , CC: Bjorn Helgaas , , Sergey Miroshnichenko , , Christoph Hellwig Subject: [PATCH v5 21/23] nvme-pci: Handle movable BARs Date: Fri, 16 Aug 2019 19:50:59 +0300 Message-ID: <20190816165101.911-22-s.miroshnichenko@yadro.com> X-Mailer: git-send-email 2.21.0 In-Reply-To: <20190816165101.911-1-s.miroshnichenko@yadro.com> References: <20190816165101.911-1-s.miroshnichenko@yadro.com> MIME-Version: 1.0 X-Originating-IP: [172.17.15.60] X-ClientProxiedBy: T-EXCH-01.corp.yadro.com (172.17.10.101) To T-EXCH-02.corp.yadro.com (172.17.10.102) Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org Hotplugged 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. Before the hotplugging: % 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: Sergey Miroshnichenko --- drivers/nvme/host/pci.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/drivers/nvme/host/pci.c b/drivers/nvme/host/pci.c index db160cee42ad..a805d80082ca 100644 --- a/drivers/nvme/host/pci.c +++ b/drivers/nvme/host/pci.c @@ -1645,7 +1645,7 @@ 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; @@ -2980,6 +2980,23 @@ static void nvme_error_resume(struct pci_dev *pdev) flush_work(&dev->ctrl.reset_work); } +static void nvme_rescan_prepare(struct pci_dev *pdev) +{ + struct nvme_dev *dev = pci_get_drvdata(pdev); + + nvme_dev_disable(dev, false); + 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_sync(&dev->ctrl); +} + static const struct pci_error_handlers nvme_err_handler = { .error_detected = nvme_error_detected, .slot_reset = nvme_slot_reset, @@ -3049,6 +3066,8 @@ 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, }; static int __init nvme_init(void)