Messages in this thread | | | Date | Thu, 29 Nov 2007 17:28:33 +0100 | From | Cornelia Huck <> | Subject | Re: [RFC] New kobject/kset/ktype documentation and example code |
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On Thu, 29 Nov 2007 10:47:19 -0500 (EST), Alan Stern <stern@rowland.harvard.edu> wrote:
> On Thu, 29 Nov 2007, Cornelia Huck wrote: > > > > The only problem arises when a child's driver retains a reference to > > > the parent kobject. If things are done properly, this reference should > > > involve incrementing the module count -- which would prevent the module > > > from being unloaded in the first place. > > > > This still leaves the possibility that random code may grab a reference > > once the kobject is present in the tree and lookupable. You gave up the > > control of the number of references to your object once you made it > > public. > > I don't agree with this argument. Code should never grab random > references without insuring that the owner of the referenced object is > pinned. This rule applies to everything, not just kobjects.
Of course. You don't necessarily need prevent module unloading, but pin the module in memory until the last reference is gone.
> Unfortunately kobjects don't have an owner field. In practice this > means that it isn't possible to pin the owner of some random kobject -- > you have to know where the kobject came from or what it's embedded in. > All users of kobjects need to work this way.
Yeah, that is what the-patchset-I-have-to-dig-around-for does: Introduce an owner field in the kobject for pinning the module. (IIRC, you even did some of the patches?) - 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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