Re: [PATCH 2/9] fs: fix empty-body warning in posix_acl.c

[Linus Torvalds]

On Sat, Apr 18, 2020 at 11:41 AM Randy Dunlap <rdunlap@xxxxxxxxxxxxx> wrote:
>
> Fix gcc empty-body warning when -Wextra is used:

Please don't do this.

First off, "do_empty()" adds nothing but confusion. Now it
syntactically looks like it does something, and it's a new pattern to
everybody. I've never seen it before.

Secondly, even if we were to do this, then the patch would be wrong:

>         if (cmpxchg(p, ACL_NOT_CACHED, sentinel) != ACL_NOT_CACHED)
> -               /* fall through */ ;
> +               do_empty(); /* fall through */

That comment made little sense before, but it makes _no_ sense now.

What fall-through? I'm guessing it meant to say "nothing", and
somebody was confused. With "do_empty()", it's even more confusing.

Thirdly, there's a *reason* why "-Wextra" isn't used.

The warnings enabled by -Wextra are usually complete garbage, and
trying to fix them often makes the code worse. Exactly like here.

             Linus