On Mon, 18 Aug 2008, Anthony Liguori wrote:
Nothing. It works just fine. However, I implemented it more verbosely
because this is the second time we've "fixed" this problem. See
commit bdc1681cdf1ab6a65fa935a2b3f8fc63b20c54ea
Author: Rusty Russell [off-list ref]
Date: Mon Mar 17 22:58:15 2008 -0500
virtio: handle > 2 billion page balloon targets
Well, we could perhaps add a sparse warning that makes noise when a
unsigned subtraction is cast to a wider signed field. I dunno if it would
catch anything interesting, or just cause a ton of irritating noise.
So I thought I'd rely a little less on the subtleties of promotion and make
things a bit more clear. However, I don't feel that strongly about it so here
you go.
Ugly and inefficient is not acceptable, even for these kinds of reasons.
So yes, the simpler version is much better.
Linus