On Sat, Sep 30, 2017 at 10:12:05AM +0200, Greg Kroah-Hartman wrote: > On Fri, Sep 29, 2017 at 06:52:28PM -0700, Darren Hart wrote: > > > > 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@xxxxxxxx> > > > --- > > > drivers/platform/x86/wmi.c | 98 +++++++++++++++++++++++++++++++++++++++++++--- > > > include/linux/wmi.h | 1 + > > > 2 files changed, 94 insertions(+), 5 deletions(-) > > > > +Greg, Rafael, Matthew, and Christoph > > > > You each provided feedback regarding the method of exposing WMI methods > > to userspace. This and subsequent patches from Mario lay some of the > > core groundwork. > > > > They implement an implicit whitelist as only drivers requesting the char > > dev will see it created. > > > > https://lkml.org/lkml/2017/9/28/8 > > If you want patchs reviewed, it's best to actually cc: us on the patch > itself :( > Of course. I didn't send the series, but thought you should see it. I could have asked Mario to resend, but I thought a pointer would have made it easy enough to find in your lkml folder, and it would avoid splitting the conversation which resending would inevitably lead to. I pruned this one because Christoph gets upset if I don't. We can wait for v4 I guess. And next time I want to get your take on something someone doesn't Cc you on, I'll just ask them to resend the whole series with you on Cc. -- Darren Hart VMware Open Source Technology Center
