Messages in this thread | | | Date | Wed, 28 Nov 2007 17:51:08 +0100 | From | Cornelia Huck <> | Subject | Re: [RFC] New kobject/kset/ktype documentation and example code |
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On Wed, 28 Nov 2007 17:36:29 +0100, Kay Sievers <kay.sievers@vrfy.org> wrote:
> > On Wed, 2007-11-28 at 17:12 +0100, Cornelia Huck wrote: > > On Wed, 28 Nov 2007 16:57:48 +0100, > > Kay Sievers <kay.sievers@vrfy.org> wrote: > > > > > On Wed, 2007-11-28 at 16:48 +0100, Cornelia Huck wrote: > > > > On Wed, 28 Nov 2007 13:23:02 +0100, > > > > Kay Sievers <kay.sievers@vrfy.org> wrote: > > > > > On Wed, 2007-11-28 at 12:45 +0100, Cornelia Huck wrote: > > > > > > On Tue, 27 Nov 2007 15:02:52 -0800, Greg KH <greg@kroah.com> wrote: > > > > > > > > > > The uevent function will be called when the uevent is about to be sent to > > > > > > > userspace to allow more environment variables to be added to the uevent. > > > > > > > > > > > > It may be helpful to mention which uevents are by default created by > > > > > > the kobject core (KOBJ_ADD, KOBJ_DEL, KOBJ_MOVE). > > > > > > > > > > I think, we should remove all these default events from the kobject > > > > > core. We will not be able to manage the timing issues and "raw" kobject > > > > > users should request the events on their own, when they are finished > > > > > adding stuff to the kobject. I see currently no way to solve the > > > > > "attributes created after the event" problem. The new > > > > > *_create_and_register functions do not allow default attributes to be > > > > > created, which will just lead to serious trouble when someone wants to > > > > > use udev to set defaults and such things. We may just want to require an > > > > > explicit call to send the event? > > > > > > > > There will always be attributes that will show up later (for example, > > > > after a device is activated). Probably the best approach is to keep the > > > > default uevents, but have the attribute-adder send another uevent when > > > > they are done? > > > > > > Uh, that's more an exception where we can't give guarantees because of > > > very specific hardware setups, and it would be an additional "change" > > > event. There are valid cases for this, but only a _very_ few. > > > > > > There is absolutely no reason not to do it right with the "add" event, > > > just because we are too lazy to solve it proper the current code. It's > > > just so broken by design, what we are doing today. :) > > > > I'm worrying a bit about changes that impact the whole code tree in > > lots of places. I'd be fine with the device layer doing its uevent > > manually in device_add() at the very end, though. (This would allow > > drivers to add attributes in their probe function before the uevent, > > for example.)
<Looks at device_add() again: It already throws the uevent manually...>
> > The driver core does use the split already in most places, I did that > long ago. There are not too many (~20) users of kobject_register(), and > it's a pretty straight-forward change to change that to _init, _add, > _uevent, and get rid of that totally useless "convenience api". > > I think there is no longer any excuse to keep that broken code around, > and even require to document that it's broken. The whole purpose of the > uevent is userspace consumption, which just doesn't work correctly with > the code we offer. The fix is trivial, and should be done now, and we no > longer need to fiddle around timing issues, just because we are too > lazy. > > I propose the removal of _all_ funtions that have *register* in their > name, and always require the following sequence: > _init() > _add() > _uevent(_ADD) > > _uevent(_REMOVE) > _del() > _put() > > The _create_and_register() functions would become _create_ and_add() > and will need an additional _uevent() call after they populated the > object.
I'm absolutely fine with doing that at the kobject level (after all, it's a quite contained change, and the uevent function explicitely works on a kobject).
For the other _register()/_unregister() functions, it's a different piece of cake. They are: - distributed through lot of different code - at a higher level than kobjects, and kobject_uevent() acts on the kobject - usually encapsulating a sequence that wants to be used by almost all callers, and that includes a uevent
I don't think we want people registering a higher level object and then wondering why udev doesn't seem to take notice of it. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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