From mboxrd@z Thu Jan 1 00:00:00 1970 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 4BEF3C433EF for ; Mon, 31 Jan 2022 16:21:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232764AbiAaQU7 (ORCPT ); Mon, 31 Jan 2022 11:20:59 -0500 Received: from frasgout.his.huawei.com ([185.176.79.56]:4573 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1358518AbiAaQU5 (ORCPT ); Mon, 31 Jan 2022 11:20:57 -0500 Received: from fraeml713-chm.china.huawei.com (unknown [172.18.147.200]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4JnYFP1Pc1z67yjQ; Tue, 1 Feb 2022 00:20:25 +0800 (CST) Received: from lhreml710-chm.china.huawei.com (10.201.108.61) by fraeml713-chm.china.huawei.com (10.206.15.32) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Mon, 31 Jan 2022 17:20:56 +0100 Received: from localhost (10.47.73.212) by lhreml710-chm.china.huawei.com (10.201.108.61) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.2308.21; Mon, 31 Jan 2022 16:20:55 +0000 Date: Mon, 31 Jan 2022 16:20:50 +0000 From: Jonathan Cameron To: Dan Williams CC: , , Subject: Re: [PATCH v3 19/40] cxl/port: Up-level cxl_add_dport() locking requirements to the caller Message-ID: <20220131162050.000076b1@Huawei.com> In-Reply-To: <164298422000.3018233.4106867312927858722.stgit@dwillia2-desk3.amr.corp.intel.com> References: <164298411792.3018233.7493009997525360044.stgit@dwillia2-desk3.amr.corp.intel.com> <164298422000.3018233.4106867312927858722.stgit@dwillia2-desk3.amr.corp.intel.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.0.0 (GTK+ 3.24.29; i686-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.47.73.212] X-ClientProxiedBy: lhreml704-chm.china.huawei.com (10.201.108.53) To lhreml710-chm.china.huawei.com (10.201.108.61) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-cxl@vger.kernel.org On Sun, 23 Jan 2022 16:30:20 -0800 Dan Williams wrote: > In preparation for moving dport enumeration into the core, require the > port device lock to be acquired by the caller. > > Signed-off-by: Dan Williams Why does it make sense to drop the cxl_device_lock() lockdep stuff in the paths affected here? > --- > drivers/cxl/acpi.c | 2 ++ > drivers/cxl/core/port.c | 3 +-- > tools/testing/cxl/mock_acpi.c | 4 ++++ > 3 files changed, 7 insertions(+), 2 deletions(-) > > diff --git a/drivers/cxl/acpi.c b/drivers/cxl/acpi.c > index ab2b76532272..e596dc375267 100644 > --- a/drivers/cxl/acpi.c > +++ b/drivers/cxl/acpi.c > @@ -342,7 +342,9 @@ static int add_host_bridge_dport(struct device *match, void *arg) > return 0; > } > > + device_lock(&root_port->dev); > rc = cxl_add_dport(root_port, match, uid, ctx.chbcr); > + device_unlock(&root_port->dev); > if (rc) { > dev_err(host, "failed to add downstream port: %s\n", > dev_name(match)); > diff --git a/drivers/cxl/core/port.c b/drivers/cxl/core/port.c > index ec9587e52423..c51a10154e29 100644 > --- a/drivers/cxl/core/port.c > +++ b/drivers/cxl/core/port.c > @@ -516,7 +516,7 @@ static int add_dport(struct cxl_port *port, struct cxl_dport *new) > { > struct cxl_dport *dup; > > - cxl_device_lock(&port->dev); > + device_lock_assert(&port->dev); > dup = find_dport(port, new->port_id); > if (dup) > dev_err(&port->dev, > @@ -525,7 +525,6 @@ static int add_dport(struct cxl_port *port, struct cxl_dport *new) > dev_name(dup->dport)); > else > list_add_tail(&new->list, &port->dports); > - cxl_device_unlock(&port->dev); > > return dup ? -EEXIST : 0; > } > diff --git a/tools/testing/cxl/mock_acpi.c b/tools/testing/cxl/mock_acpi.c > index 4c8a493ace56..667c032ccccf 100644 > --- a/tools/testing/cxl/mock_acpi.c > +++ b/tools/testing/cxl/mock_acpi.c > @@ -57,7 +57,9 @@ static int match_add_root_port(struct pci_dev *pdev, void *data) > > /* TODO walk DVSEC to find component register base */ > port_num = FIELD_GET(PCI_EXP_LNKCAP_PN, lnkcap); > + device_lock(&port->dev); > rc = cxl_add_dport(port, &pdev->dev, port_num, CXL_RESOURCE_NONE); > + device_unlock(&port->dev); > if (rc) { > dev_err(dev, "failed to add dport: %s (%d)\n", > dev_name(&pdev->dev), rc); > @@ -78,7 +80,9 @@ static int mock_add_root_port(struct platform_device *pdev, void *data) > struct device *dev = ctx->dev; > int rc; > > + device_lock(&port->dev); > rc = cxl_add_dport(port, &pdev->dev, pdev->id, CXL_RESOURCE_NONE); > + device_unlock(&port->dev); > if (rc) { > dev_err(dev, "failed to add dport: %s (%d)\n", > dev_name(&pdev->dev), rc); >