Re: guard coding style (was: Re: [PATCH v1 05/10] gpio: pca953x: Simplify code with cleanup helpers)

[Peter Zijlstra]

On Fri, Sep 15, 2023 at 12:26:39AM +0200, Peter Zijlstra wrote:
> On Thu, Sep 14, 2023 at 01:51:01PM -0700, Mitchell Levy wrote:
> 
> > The more I think on this issue, the more I go back and forth. If we
> > only had guard(...), the only way to approximate scoped guard would be
> > to either just do what the macro does (i.e., a dummy for loop that
> > only runs once) or use an anonymous scope, e.g.,
> > {
> >     guard(...);
> >     my_one_statement();
> > }
> > Since this is how I've previously used std::lock_guard in C++, this
> > pattern feels very familiar to me, and the scoped_guard feels almost
> > like syntax sugar for this. As such, I feel like including the braces
> > is most natural because, as Geert mentioned, it emphasizes the scope
> > that "should" (in my brain, at least) be there.
> 
> AFAIC the anonymous scope thing doesn't much happen in kernel coding
> style -- although I'm sure it's there, the code-base is simply too vast
> to not have it *somewhere*.

The kernel typical style would be:

	do {
		...
	} while (0)

to create a 'pointless' scope. Apparently this is also what I've done in
some conversions where a conditional lock was involved.