Re: [patch] drivers: wait for threaded probes between initcall levels

Andrew Morton
2006-10-28T05:35:59Z

On Fri, 27 Oct 2006 22:19:25 -0700
Andrew Morton <akpm@osdl.org> wrote:

> The simplest implementation of "A needs B to have run" is for A to simply
> call B, and B arranges to not allow itself to be run more than once.
>
> But that doesn't work in the case "A needs B to be run, but only if B is
> present". Resolving this one would require something like a fancy
> "synchronisation object" against which dependers and dependees can register
> interest, and a core engine which takes care of the case where a depender
> registers against something which no dependees have registered.

otoh, we could stick with the simple "A calls B" solution, and A also
provides an attribute-weak implementation of B to cover the "A needs B but
only if B is present" problems.

Had to say, really - one would need to study some specific problem cases.