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 31032CA0FE6 for ; Fri, 1 Sep 2023 09:08:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1348715AbjIAJI2 (ORCPT ); Fri, 1 Sep 2023 05:08:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41462 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234319AbjIAJI1 (ORCPT ); Fri, 1 Sep 2023 05:08:27 -0400 Received: from frasgout.his.huawei.com (frasgout.his.huawei.com [185.176.79.56]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 791CC91; Fri, 1 Sep 2023 02:08:24 -0700 (PDT) Received: from lhrpeml500005.china.huawei.com (unknown [172.18.147.207]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4RcXGn3LsSz6HJpQ; Fri, 1 Sep 2023 17:07:13 +0800 (CST) Received: from localhost (10.202.227.76) by lhrpeml500005.china.huawei.com (7.191.163.240) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2507.31; Fri, 1 Sep 2023 10:08:21 +0100 Date: Fri, 1 Sep 2023 10:08:20 +0100 From: Jonathan Cameron To: Robert Richter CC: Terry Bowman , , , , , , , , , Subject: Re: [PATCH v9 02/15] cxl/regs: Prepare for multiple users of register mappings Message-ID: <20230901100820.000027fb@Huawei.com> In-Reply-To: References: <20230825233211.3029825-1-terry.bowman@amd.com> <20230825233211.3029825-3-terry.bowman@amd.com> <20230829145254.00003259@Huawei.com> Organization: Huawei Technologies Research and Development (UK) Ltd. X-Mailer: Claws Mail 4.1.0 (GTK 3.24.33; x86_64-w64-mingw32) MIME-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.76] X-ClientProxiedBy: lhrpeml500006.china.huawei.com (7.191.161.198) To lhrpeml500005.china.huawei.com (7.191.163.240) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 31 Aug 2023 14:43:53 +0200 Robert Richter wrote: > On 29.08.23 14:52:54, Jonathan Cameron wrote: > > On Fri, 25 Aug 2023 18:31:58 -0500 > > Terry Bowman wrote: > > > > > From: Robert Richter > > > > > > The function devm_cxl_iomap_block() is used to map register mappings > > > of CXL component or device registers. A @dev is used to unmap the IO > > > regions during device removal. > > > > > > Now, there are multiple devices using the register mappings. E.g. the > > > RAS cap of the Component Registers is used by cxl_pci, the HDM cap > > > used in cxl_mem. This could cause IO blocks not being freed and a > > > subsequent reinitialization to fail if the same device is used for > > > both. > > > > > > To prevent that, expand cxl_map_component_regs() to pass a @dev to be > > > used with devm to IO unmap. This allows to pass the device that > > > actually is creating and using the IO region. > > > > > > For symmetry also change the function i/f of cxl_map_device_regs(). > > > > > > Signed-off-by: Robert Richter > > > Signed-off-by: Terry Bowman > > > > I'm not sure we should leave map->dev around after this change > > as it's not obvious where it is valid to use and where it isn't. > > > > Perhaps we just need to pass the device into the few calls > > that use it other than the ones you have here. > > I have checked that and it turned out we would need to pass @dev > through multiple functions (see cxl_setup_regs()). So I left it in as > devm is a special case (mis)using it. > > > > > This patch itself looks fine to me. > > I will take it as a Reviewed-by:? > No. I'm not convinced on the map->dev question even though I appreciate that passing it around is a mess. To me it's really non obvious that in some cases map->dev is appropriate and in others a different dev is needed. Maybe some naming change would make it clear what each one is for? Jonathan > Thanks, > > -Robert > > > > > Jonathan > > > > > --- > > > drivers/cxl/core/hdm.c | 3 ++- > > > drivers/cxl/core/regs.c | 4 ++-- > > > drivers/cxl/cxl.h | 2 ++ > > > drivers/cxl/pci.c | 4 ++-- > > > 4 files changed, 8 insertions(+), 5 deletions(-) > > > > > > diff --git a/drivers/cxl/core/hdm.c b/drivers/cxl/core/hdm.c > > > index 4449b34a80cc..17c8ba8c75e0 100644 > > > --- a/drivers/cxl/core/hdm.c > > > +++ b/drivers/cxl/core/hdm.c > > > @@ -98,7 +98,8 @@ static int map_hdm_decoder_regs(struct cxl_port *port, void __iomem *crb, > > > return -ENODEV; > > > } > > > > > > - return cxl_map_component_regs(&map, regs, BIT(CXL_CM_CAP_CAP_ID_HDM)); > > > + return cxl_map_component_regs(&map, &port->dev, regs, > > > + BIT(CXL_CM_CAP_CAP_ID_HDM)); > > > } > > > > > > static bool should_emulate_decoders(struct cxl_endpoint_dvsec_info *info) > > > diff --git a/drivers/cxl/core/regs.c b/drivers/cxl/core/regs.c > > > index 6281127b3e9d..dfc3e272e7d8 100644 > > > --- a/drivers/cxl/core/regs.c > > > +++ b/drivers/cxl/core/regs.c > > > @@ -201,10 +201,10 @@ void __iomem *devm_cxl_iomap_block(struct device *dev, resource_size_t addr, > > > } > > > > > > int cxl_map_component_regs(const struct cxl_register_map *map, > > > + struct device *dev, > > > struct cxl_component_regs *regs, > > > unsigned long map_mask) > > > { > > > - struct device *dev = map->dev; > > > struct mapinfo { > > > const struct cxl_reg_map *rmap; > > > void __iomem **addr; > > > @@ -235,9 +235,9 @@ int cxl_map_component_regs(const struct cxl_register_map *map, > > > EXPORT_SYMBOL_NS_GPL(cxl_map_component_regs, CXL); > > > > > > int cxl_map_device_regs(const struct cxl_register_map *map, > > > + struct device *dev, > > > struct cxl_device_regs *regs) > > > { > > > - struct device *dev = map->dev; > > > resource_size_t phys_addr = map->resource; > > > struct mapinfo { > > > const struct cxl_reg_map *rmap; > > > diff --git a/drivers/cxl/cxl.h b/drivers/cxl/cxl.h > > > index 76d92561af29..ec8ba9ebcf64 100644 > > > --- a/drivers/cxl/cxl.h > > > +++ b/drivers/cxl/cxl.h > > > @@ -274,9 +274,11 @@ void cxl_probe_component_regs(struct device *dev, void __iomem *base, > > > void cxl_probe_device_regs(struct device *dev, void __iomem *base, > > > struct cxl_device_reg_map *map); > > > int cxl_map_component_regs(const struct cxl_register_map *map, > > > + struct device *dev, > > > struct cxl_component_regs *regs, > > > unsigned long map_mask); > > > int cxl_map_device_regs(const struct cxl_register_map *map, > > > + struct device *dev, > > > struct cxl_device_regs *regs); > > > int cxl_map_pmu_regs(struct pci_dev *pdev, struct cxl_pmu_regs *regs, > > > struct cxl_register_map *map); > > > diff --git a/drivers/cxl/pci.c b/drivers/cxl/pci.c > > > index 48f88d96029d..88ddcff8a0b2 100644 > > > --- a/drivers/cxl/pci.c > > > +++ b/drivers/cxl/pci.c > > > @@ -827,7 +827,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > > > if (rc) > > > return rc; > > > > > > - rc = cxl_map_device_regs(&map, &cxlds->regs.device_regs); > > > + rc = cxl_map_device_regs(&map, cxlds->dev, &cxlds->regs.device_regs); > > > if (rc) > > > return rc; > > > > > > @@ -844,7 +844,7 @@ static int cxl_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id) > > > > > > cxlds->component_reg_phys = map.resource; > > > > > > - rc = cxl_map_component_regs(&map, &cxlds->regs.component, > > > + rc = cxl_map_component_regs(&map, cxlds->dev, &cxlds->regs.component, > > > BIT(CXL_CM_CAP_CAP_ID_RAS)); > > > if (rc) > > > dev_dbg(&pdev->dev, "Failed to map RAS capability.\n"); > >