On Fri, 2011-05-13 at 14:54 +0200, Ingo Molnar wrote: > I think the sanest semantics is to run all active callbacks as well. > > For example if this is used for three stacked security policies - as if 3 LSM > modules were stacked at once. We'd call all three, and we'd determine that at > least one failed - and we'd return a failure. But that only works for boolean functions where you can return the multi-bit-or of the result. What if you need to return the specific error code. Also, there's bound to be other cases where people will want to employ this, look at all the various notifier chain muck we've got, it already deals with much of this -- simply because users need it. Then there's the whole indirection argument, if you don't need indirection, its often better to not use it, I myself much prefer code to look like: foo1(bar); foo2(bar); foo3(bar); Than: foo_notifier(bar); Simply because its much clearer who all are involved without me having to grep around to see who registers for foo_notifier and wth they do with it. It also makes it much harder to sneak in another user, whereas its nearly impossible to find new notifier users. Its also much faster, no extra memory accesses, no indirect function calls, no other muck.
