judgement call, the decision based more on real world
constraints people face than what the paper standard says.
+ - Fixing style violations while working on a real change as a
+ preparatory clean-up step is good, but otherwise avoid useless code
+ churn for the sake of conforming to the style.
+
+ "Once it _is_ in the tree, it's not really worth the patch noise to
+ go and fix it up."
+ Cf. http://article.gmane.org/gmane.linux.kernel/943020
+
Make your code readable and sensible, and don't try to be clever.
As for more concrete guidelines, just imitate the existing code