From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751951AbdCCOIF (ORCPT ); Fri, 3 Mar 2017 09:08:05 -0500 Received: from mx1.redhat.com ([209.132.183.28]:60878 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751415AbdCCOIE (ORCPT ); Fri, 3 Mar 2017 09:08:04 -0500 Subject: Re: [PATCH 2/3] mmc: sdhci-acpi: Check device status before calling fix_up_power() To: Jean Delvare References: <20170225172357.26294-1-hdegoede@redhat.com> <20170225172357.26294-3-hdegoede@redhat.com> <20170303100905.090e0364@endymion> Cc: Adrian Hunter , Ulf Hansson , Jean Delvare , Takashi Iwai , russianneuromancer@ya.ru, linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org, Hans de Goede From: Hans de Goede Message-ID: Date: Fri, 3 Mar 2017 14:59:50 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0 MIME-Version: 1.0 In-Reply-To: <20170303100905.090e0364@endymion> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Fri, 03 Mar 2017 13:59:55 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On 03-03-17 10:09, Jean Delvare wrote: > Hi Hans, Adrian, > > On Sat, 25 Feb 2017 18:23:56 +0100, Hans de Goede wrote: >> Calling acpi_device_fix_up_power() on a device which is not present >> is not a good idea. > > How bad is it? Not that bad really, thinking more about this, since drivers/mmc/host/sdhci-acpi.c is a platform driver, its probe function will never get called if !device->status.present, since the acpi-subsys then will not instantiate a platform device for the acpi-dev in question at all. So a better fix would be to just drop the superfluous check. I'll send a new version doing this. Regards, Hans > > This was introduced by commit e5bbf30733f9, which was backported to > several stable branches. If it causes real trouble then this fix-up > patch should be annotated with > > Fixes: e5bbf30733f9 ("mmc: sdhci-acpi: Ensure connected devices are powered when") > > and Cc's to stable@, so it can be propagated to all affected trees. > >> While at it also call acpi_bus_get_status() on the children before >> the status check to make sure that child->status contains valid data. >> >> Signed-off-by: Hans de Goede >> --- >> drivers/mmc/host/sdhci-acpi.c | 6 +++--- >> 1 file changed, 3 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c >> index 96465ff..873beae 100644 >> --- a/drivers/mmc/host/sdhci-acpi.c >> +++ b/drivers/mmc/host/sdhci-acpi.c >> @@ -394,15 +394,15 @@ static int sdhci_acpi_probe(struct platform_device *pdev) >> if (acpi_bus_get_device(handle, &device)) >> return -ENODEV; >> >> + if (acpi_bus_get_status(device) || !device->status.present) >> + return -ENODEV; >> + >> /* Power on the SDHCI controller and its children */ >> acpi_device_fix_up_power(device); >> list_for_each_entry(child, &device->children, node) >> if (child->status.present && child->status.enabled) >> acpi_device_fix_up_power(child); >> >> - if (acpi_bus_get_status(device) || !device->status.present) >> - return -ENODEV; >> - >> if (sdhci_acpi_byt_defer(dev)) >> return -EPROBE_DEFER; >> > >