Messages in this thread | | | Date | Wed, 10 Jul 2013 15:34:38 -0700 | From | Guenter Roeck <> | Subject | Re: Driver core and sysfs changes for attribute groups |
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On Wed, Jul 10, 2013 at 03:23:37PM -0700, Greg Kroah-Hartman wrote: > On Wed, Jul 10, 2013 at 03:04:41PM -0700, Guenter Roeck wrote: > > On Wed, Jul 10, 2013 at 01:05:08PM -0700, Greg Kroah-Hartman wrote: > > > Hi all, > > > > > > Guenter and Oliver have been pointing out a few limitations of the > > > driver core's ability to create files properly (i.e. in a way that > > > doesn't race with userspace.) The driver core allows this, but it > > > doesn't export that ability to drivers very easily, and for binary > > > files, not at all. > > > > > > So here's a set of 6 patches that I'll be queueing up to go to Linus in > > > time for 3.11 so that people can start using them in their driver > > > subsystems. It adds some new macros to make using attributes and > > > attribute groups easier, adds binary file capabilities to attribute > > > groups, and finally, lets subsystems (like platform drivers) set a > > > attribute group for when their device is created. > > > > > > If anyone has any problems with these patches, please let me know. > > > > > > Guenter, I've tweaked your original patch a bit, changing the name of > > > the function and putting the kernel doc comments in the correct place so > > > the build doesn't complain about it. > > > > > I like it - thanks a lot for picking that up. I think there are several > > drivers who could and should use the new API call (gpio, infiniband/umad, > > c2port, ptp, scsi/osst, android/timed_output, asus_oled are some examples). > > Yes, I'll be sweeping the tree for the next few released doing all of > this. The amount of sysfs "cruft" that has accumulated in the past few > years since I last looked is crazy... > > > For hwmon, I ended up having to handle device creation internally after all. > > Reason is that I also had to set device->type to a new hwmon device type. > > That in turn was necessary to be able to support the hwmon 'name' attribute > > properly (it has to be optional, meaning I could not use class->dev_attrs but > > had to use device_type->groups instead). I hope I can send out a revised > > series of patches soon .. only I'll leave for pto next week and I am bugged > > down with other work right now, so it may have to wait until after I return. > > > > Wonder if it would make sense to support a core driver API call for that > > purpose as well - ie one that not only has the additional groups argument, > > but one that (also ?) accepts a pointer to the the device type. I didn't spend > > any time tracking down potential users, though, so I may be off track here. > > I don't understand the problem, for USB we have different "types" of > devices on the bus just fine. Or are you saying that the function you > created isn't going to be used in the hwmon core in the end? > > I doubt device_create() really needs to worry about different types, but > I could be wrong :) > All I needed was the dev_groups field you just added to the class structure. I am currently merging your patches into my code, so you'll get some free test coverage ...
Thanks, Guenter
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