From: <Mario.Limonciello@dell.com>
To: <greg@kroah.com>
Cc: <dvhart@infradead.org>, <andy.shevchenko@gmail.com>,
<linux-kernel@vger.kernel.org>,
<platform-driver-x86@vger.kernel.org>, <luto@kernel.org>,
<quasisec@google.com>, <pali.rohar@gmail.com>
Subject: RE: [PATCH v3 4/8] platform/x86: wmi: create character devices when requested by drivers
Date: Tue, 3 Oct 2017 15:13:35 +0000 [thread overview]
Message-ID: <f5c36f19007e486ba18f488d4c17363f@ausx13mpc120.AMER.DELL.COM> (raw)
In-Reply-To: <20171003092342.GB13295@kroah.com>
> -----Original Message-----
> From: Greg KH [mailto:greg@kroah.com]
> Sent: Tuesday, October 3, 2017 4:24 AM
> To: Limonciello, Mario <Mario_Limonciello@Dell.com>
> Cc: dvhart@infradead.org; Andy Shevchenko <andy.shevchenko@gmail.com>;
> LKML <linux-kernel@vger.kernel.org>; platform-driver-x86@vger.kernel.org;
> Andy Lutomirski <luto@kernel.org>; quasisec@google.com;
> pali.rohar@gmail.com
> Subject: Re: [PATCH v3 4/8] platform/x86: wmi: create character devices when
> requested by drivers
>
> On Wed, Sep 27, 2017 at 11:02:16PM -0500, Mario Limonciello wrote:
> > For WMI operations that are only Set or Query read or write sysfs
> > attributes created by WMI vendor drivers make sense.
> >
> > For other WMI operations that are run on Method, there needs to be a
> > way to guarantee to userspace that the results from the method call
> > belong to the data request to the method call. Sysfs attributes don't
> > work well in this scenario because two userspace processes may be
> > competing at reading/writing an attribute and step on each other's
> > data.
> >
> > When a WMI vendor driver declares a set of functions in a
> > file_operations object the WMI bus driver will create a character
> > device that maps to those file operations.
> >
> > That character device will correspond to this path:
> > /dev/wmi/$driver
> >
> > This policy is selected as one driver may map and use multiple
> > GUIDs and it would be better to only expose a single character
> > device.
> >
> > The WMI vendor drivers will be responsible for managing access to
> > this character device and proper locking on it.
> >
> > When a WMI vendor driver is unloaded the WMI bus driver will clean
> > up the character device.
> >
> > Signed-off-by: Mario Limonciello <mario.limonciello@dell.com>
> > ---
> > drivers/platform/x86/wmi.c | 98
> +++++++++++++++++++++++++++++++++++++++++++---
> > include/linux/wmi.h | 1 +
> > 2 files changed, 94 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/platform/x86/wmi.c b/drivers/platform/x86/wmi.c
> > index 4d73a87c2ddf..17399df87948 100644
> > --- a/drivers/platform/x86/wmi.c
> > +++ b/drivers/platform/x86/wmi.c
> > @@ -34,7 +34,9 @@
> > #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
> >
> > #include <linux/acpi.h>
> > +#include <linux/cdev.h>
> > #include <linux/device.h>
> > +#include <linux/idr.h>
> > #include <linux/init.h>
> > #include <linux/kernel.h>
> > #include <linux/list.h>
> > @@ -50,6 +52,9 @@ MODULE_AUTHOR("Carlos Corbacho");
> > MODULE_DESCRIPTION("ACPI-WMI Mapping Driver");
> > MODULE_LICENSE("GPL");
> >
> > +#define WMI_MAX_DEVS MINORMASK
> > +static DEFINE_IDR(wmi_idr);
>
> You never free the idr's memory when you unload the module :(
Whoops thanks, will fix. ☹
next prev parent reply other threads:[~2017-10-03 15:18 UTC|newest]
Thread overview: 56+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-09-28 4:02 [PATCH v3 0/8] Introduce support for Dell SMBIOS over WMI Mario Limonciello
2017-09-28 4:02 ` [PATCH v3 1/8] platform/x86: wmi: Add new method wmidev_evaluate_method Mario Limonciello
2017-09-28 4:02 ` [PATCH v3 2/8] platform/x86: dell-smbios: Introduce a WMI-ACPI interface Mario Limonciello
2017-09-28 6:53 ` Pali Rohár
2017-09-28 22:43 ` Mario.Limonciello
2017-09-29 7:35 ` Pali Rohár
2017-09-30 20:01 ` Mario.Limonciello
2017-09-30 21:06 ` Pali Rohár
2017-09-30 0:51 ` Darren Hart
2017-09-30 7:15 ` Pali Rohár
2017-09-30 19:56 ` Mario.Limonciello
2017-09-28 4:02 ` [PATCH v3 3/8] platform/x86: dell-wmi-smbios: Use Dell WMI descriptor check Mario Limonciello
2017-09-30 1:29 ` Darren Hart
2017-09-30 19:48 ` Mario.Limonciello
2017-09-30 20:01 ` Pali Rohár
2017-10-02 14:15 ` Mario.Limonciello
2017-10-02 14:37 ` Pali Rohár
2017-10-01 8:43 ` Andy Shevchenko
2017-09-28 4:02 ` [PATCH v3 4/8] platform/x86: wmi: create character devices when requested by drivers Mario Limonciello
2017-09-30 1:52 ` Darren Hart
2017-09-30 8:12 ` Greg Kroah-Hartman
2017-09-30 19:26 ` Mario.Limonciello
2017-10-01 13:23 ` Greg KH
2017-10-01 14:25 ` Mario.Limonciello
2017-10-01 18:03 ` Greg KH
2017-10-02 0:57 ` Darren Hart
2017-10-02 9:24 ` Greg Kroah-Hartman
2017-10-02 14:33 ` Darren Hart
2017-10-03 9:23 ` Greg KH
2017-10-03 15:09 ` Mario.Limonciello
2017-10-03 15:10 ` Darren Hart
2017-10-03 16:48 ` Andy Lutomirski
2017-10-03 17:46 ` Greg KH
2017-10-03 18:38 ` Mario.Limonciello
2017-10-03 19:31 ` Andy Lutomirski
2017-10-03 9:23 ` Greg KH
2017-10-03 15:13 ` Mario.Limonciello [this message]
2017-09-28 4:02 ` [PATCH v3 5/8] platform/x86: dell-wmi-smbios: introduce character device for userspace Mario Limonciello
2017-09-30 2:06 ` Darren Hart
2017-09-30 19:45 ` Mario.Limonciello
2017-10-03 9:26 ` Greg KH
2017-10-03 15:09 ` Mario.Limonciello
2017-10-03 15:20 ` Darren Hart
2017-10-03 15:49 ` Mario.Limonciello
2017-10-05 0:02 ` Darren Hart
2017-10-05 15:10 ` Mario.Limonciello
2017-09-28 4:02 ` [PATCH v3 6/8] platform/x86: dell-wmi-smbios: Add a sysfs interface for SMBIOS tokens Mario Limonciello
2017-09-30 2:10 ` Darren Hart
2017-10-01 8:51 ` Andy Shevchenko
2017-09-28 4:02 ` [PATCH v3 7/8] platform/x86: Kconfig: Change the default settings for dell-wmi-smbios Mario Limonciello
2017-09-28 4:02 ` [PATCH v3 8/8] platform/x86: dell-wmi-smbios: clean up wmi descriptor check Mario Limonciello
2017-10-02 13:15 ` Andy Shevchenko
2017-10-02 13:26 ` Mario.Limonciello
2017-09-30 2:16 ` [PATCH v3 0/8] Introduce support for Dell SMBIOS over WMI Darren Hart
2017-09-30 19:56 ` Mario.Limonciello
2017-10-05 2:44 ` Darren Hart
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