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 X-Spam-Level: X-Spam-Status: No, score=-5.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 C635BC76190 for ; Thu, 25 Jul 2019 18:49:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9957322BEF for ; Thu, 25 Jul 2019 18:49:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726307AbfGYSt3 (ORCPT ); Thu, 25 Jul 2019 14:49:29 -0400 Received: from mga07.intel.com ([134.134.136.100]:58904 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726195AbfGYSt3 (ORCPT ); Thu, 25 Jul 2019 14:49:29 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga105.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Jul 2019 11:49:28 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,307,1559545200"; d="scan'208";a="197980763" Received: from marshy.an.intel.com (HELO [10.122.105.159]) ([10.122.105.159]) by fmsmga002.fm.intel.com with ESMTP; 25 Jul 2019 11:49:27 -0700 Subject: Re: [PATCH 01/12 v2] Platform: add a dev_groups pointer to struct platform_driver To: Greg Kroah-Hartman , Dmitry Torokhov Cc: Johan Hovold , lkml , Romain Izard , "Rafael J. Wysocki" , Andy Shevchenko , Mans Rullgard , Bartosz Golaszewski , Randy Dunlap References: <20190704093200.GM13424@localhost> <20190704104311.GA16681@kroah.com> <20190704121143.GA5007@kroah.com> <20190706083251.GA9249@kroah.com> <20190706171948.GA23324@kroah.com> <20190719115220.GD20044@kroah.com> <20190720043857.GA14290@penguin> <20190725134411.GE11115@kroah.com> From: Richard Gong Message-ID: Date: Thu, 25 Jul 2019 14:02:03 -0500 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: <20190725134411.GE11115@kroah.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Greg, On 7/25/19 8:44 AM, Greg Kroah-Hartman wrote: > On Sat, Jul 20, 2019 at 07:38:57AM +0300, Dmitry Torokhov wrote: >> On Fri, Jul 19, 2019 at 08:52:20PM +0900, Greg Kroah-Hartman wrote: >>> On Sat, Jul 06, 2019 at 10:39:38AM -0700, Dmitry Torokhov wrote: >>>> On Sat, Jul 6, 2019 at 10:19 AM Greg Kroah-Hartman >>>> wrote: >>>>> >>>>> On Sat, Jul 06, 2019 at 10:04:39AM -0700, Dmitry Torokhov wrote: >>>>>> Hi Greg, >>>>>> >>>>>> On Sat, Jul 6, 2019 at 1:32 AM Greg Kroah-Hartman >>>>>> wrote: >>>>>>> >>>>>>> On Thu, Jul 04, 2019 at 02:17:22PM -0700, Dmitry Torokhov wrote: >>>>>>>> Hi Greg, >>>>>>>> >>>>>>>> On Thu, Jul 4, 2019 at 5:15 AM Greg Kroah-Hartman >>>>>>>> wrote: >>>>>>>>> >>>>>>>>> Platform drivers like to add sysfs groups to their device, but right now >>>>>>>>> they have to do it "by hand". The driver core should handle this for >>>>>>>>> them, but there is no way to get to the bus-default attribute groups as >>>>>>>>> all platform devices are "special and unique" one-off drivers/devices. >>>>>>>>> >>>>>>>>> To combat this, add a dev_groups pointer to platform_driver which allows >>>>>>>>> a platform driver to set up a list of default attributes that will be >>>>>>>>> properly created and removed by the platform driver core when a probe() >>>>>>>>> function is successful and removed right before the device is unbound. >>>>>>>> >>>>>>>> Why is this limited to platform bus? Drivers for other buses also >>>>>>>> often want to augment list of their attributes during probe(). I'd >>>>>>>> move it to generic probe handling. >>>>>>> >>>>>>> This is not limited to the platform at all, the driver core supports >>>>>>> this for any bus type today, but it's then up to the bus-specific code >>>>>>> to pass that on to the driver core. That's usually set for the >>>>>>> bus-specific attributes that they want exposed for all devices of that >>>>>>> bus type (see the bus_groups, dev_groups, and drv_groups pointers in >>>>>>> struct bus_type). >>>>>>> >>>>>>> For the platform devices, the problem is that this is something that the >>>>>>> individual drivers want after they bind to the device. And as all >>>>>>> platform devices are "different" they can't be a "common" set of >>>>>>> attributes, so they need to be created after the device is bound to the >>>>>>> driver. >>>>>> >>>>>> I believe that your assertion that only platform devices want to >>>>>> install custom attributes is incorrect. >>>>> >>>>> Sorry, I didn't mean to imply that only platform drivers want to do >>>>> this, as you say, many other drivers do as well. >>>>> >>>>>> Drivers for devices attached >>>>>> to serio, i2c, USB, spi, etc, etc, all have additional attributes: >>>>>> >>>>>> dtor@dtor-ws:~/kernel/work (master *)$ grep -l '\(i2c\|usb\|spi\)' >>>>>> `git grep -l '\(device_add_group\|sysfs_create_group\)' -- drivers` | >>>>>> wc -l >>>>>> 170 >>>>>> >>>>>> I am pretty sure some of this count is false positives, but majority >>>>>> is actually proper hits. >>>>> >>>>> Yeah, I know, we need to add this type of functionality to those busses >>>>> as well. I don't see a way of doing it other than this bus-by-bus >>>>> conversion, do you? >>>> >>>> Can't you push the **dev_groups from platform driver down to the >>>> generic driver structure and handle them in driver_sysfs_add()? >>> >>> Sorry for the delay, got busy with the merge window... >>> >>> Anyway, no, we can't call this then, because driver_sysfs_add() is >>> called before probe() is called. So if probe() fails, we don't bind the >>> device to the driver. We also should not be creating sysfs files for a >>> driver that has not had probe() called yet, as internal structures will >>> not be set up at that time. >> >> Ah, yes, I got confused by the fact that driver_sysfs_remove is called >> early. Anyway, I think you want something like this: > > Ah, nice, this looks good. Let me try this and see how it goes... > I tried Dmitry's patch on Intel Stratix10 platform and it works. I added one minor change on the top of Dmitry's patch, since I think we need add one additional check prior to device_add_groups(). To align with Dmitry's patch, I also change my code to use the new dev_groups pointer in the struct of device_driver. My changes are below, diff --git a/include/linux/device.h b/include/linux/device.h index 6717ade..9207aea3 100644 --- a/include/linux/device.h +++ b/include/linux/device.h @@ -296,6 +296,7 @@ struct device_driver { int (*suspend) (struct device *dev, pm_message_t state); int (*resume) (struct device *dev); const struct attribute_group **groups; + const struct attribute_group **dev_groups; const struct dev_pm_ops *pm; diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 994a907..a91e69f 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -554,9 +554,19 @@ static int really_probe(struct device *dev, struct device_driver *drv) goto probe_failed; } + if (drv->dev_groups) { + if (device_add_groups(dev, drv->dev_groups)) { + dev_err(dev, "device_add_groups(%s) failed\n", + dev_name(dev)); + goto dev_groups_failed; + } + } + if (test_remove) { test_remove = false; + device_remove_groups(dev, drv->dev_groups); + if (dev->bus->remove) dev->bus->remove(dev); else if (drv->remove) @@ -584,6 +594,12 @@ static int really_probe(struct device *dev, struct device_driver *drv) drv->bus->name, __func__, dev_name(dev), drv->name); goto done; +dev_groups_failed: + if (dev->bus->remove) + dev->bus->remove(dev); + else if (drv->remove) + drv->remove(dev); + probe_failed: if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, @@ -1114,6 +1130,8 @@ static void __device_release_driver(struct device *dev, struct device *parent) pm_runtime_put_sync(dev); + device_remove_groups(dev, drv->dev_groups); + if (dev->bus && dev->bus->remove) dev->bus->remove(dev); else if (drv->remove) diff --git a/drivers/firmware/stratix10-rsu.c b/drivers/firmware/stratix10-rsu.c index 98d8030..93b44e9 100644 --- a/drivers/firmware/stratix10-rsu.c +++ b/drivers/firmware/stratix10-rsu.c @@ -391,9 +391,9 @@ static int stratix10_rsu_remove(struct platform_device *pdev) static struct platform_driver stratix10_rsu_driver = { .probe = stratix10_rsu_probe, .remove = stratix10_rsu_remove, .driver = { .name = "stratix10-rsu", + .dev_groups = rsu_groups, }, }; Regards, Richard >> >> diff --git a/drivers/base/dd.c b/drivers/base/dd.c >> index 0df9b4461766..61d9d650d890 100644 >> --- a/drivers/base/dd.c >> +++ b/drivers/base/dd.c >> @@ -515,9 +515,17 @@ static int really_probe(struct device *dev, struct device_driver *drv) >> goto probe_failed; >> } >> >> + if (device_add_groups(dev, drv->dev_groups)) { >> + printk(KERN_ERR "%s: device_add_groups(%s) failed\n", >> + __func__, dev_name(dev)); > > dev_err() of course :) > > thanks for the review, much appreciated. > > greg k-h >