Re: [BUG] checkpatch warning default switch case

[Joe Perches <joe@perches.com>]

On Fri, 2015-12-11 at 18:56 -0300, Geyslan G. Bem wrote:
> 2015-12-11 17:21 GMT-03:00 Geyslan G. Bem <geyslan@gmail.com>:
> > 2015-12-11 17:08 GMT-03:00 Joe Perches <joe@perches.com>:
> > > On Fri, 2015-12-11 at 16:34 -0300, Geyslan G. Bem wrote:
> > > > Hello,
> > > > 
> > > > Running
> > > > scripts/checkpatch.pl -f drivers/usb/host/ehci-sched.c
> > > > 
> > > > I got this
> > > > ...
> > > > ERROR: spaces required around that ':' (ctx:VxE)
> > > > #496: FILE: drivers/usb/host/ehci-sched.c:496:
> > > > +                       default:
> > > > ...
> > > > 
> > > > 
> > > > 496:            default:
> > > >                         ehci_dbg (ehci,
> > > >                                 "periodic frame %d bogus type
> > > > %d\n",
> > > >                                 frame, type);
> > > >                 }
> > > > 
> > > > It seems a correct use of default switch case. Maybe the test
> > > > concerns
> > > > to ternary conditional.
> > > > 
> > > > Let me know.
> > > 
> > > Yes, it's a checkpatch defect.
> > > 
> > > It's because a c99 style comment is immediately before this line.
> > > 
> > >         switch (foo) {
> > >         case 1:
> > >                 break;
> > >         // foo
> > >         default:
> > >                 break;
> > >         }
> > > 
> > > emits this ERROR
> > > 
> > > I suggest you fix the comment and the message will go away.
> > Ok, I'm fixing it.
> > 
> > Tks.
> > > 
> > > Andy?  Do you care to fix this defect?
> > > 
> > 
> 
> Another false positive:
> 
> WARNING: braces {} are not necessary for single statement blocks
> #1570: FILE: drivers/usb/host/ehci-sched.c:1570:
> +               else {
> +                       start = (stream->ps.phase << 3) +
> stream->ps.phase_uf;
> +               }
> 
> The code:
> 
>         if (stream->ps.phase == NO_FRAME) {
>             int        done = 0;
> ...
>             reserve_release_iso_bandwidth(ehci, stream, 1);
>         }
> 
>         /* New stream is already scheduled; use the upcoming slot */
>         else {
>             start = (stream->ps.phase << 3) + stream->ps.phase_uf;
>         }
> 
> There's a C89 comment before the else branch and immediately before
> that an empty line. They, I think, are confusing the parser.

checkpatch isn't a real parser

Move the comment into the else block

	if (...) {
		...;
	} else {
		/* New stream ... */
		start = ...;
	}