[PATCH 001/141] afs: Fix fall-through warnings for Clang
Joe Perches
joe at perches.com
Mon Nov 23 11:51:14 EST 2020
On Mon, 2020-11-23 at 16:10 +0000, David Howells wrote:
> Joe Perches <joe at perches.com> wrote:
>
> > > call->unmarshall++;
> > > +
> > > + fallthrough;
> >
> > My preference would be to change these to break and not fallthrough;
> >
> > > case 5:
> > > break;
> > > }
>
> My preference would be to fall through. The case number is the state machine
> state, as indexed by call->unmarshall.
Then ideally the state machine states should be enums and not numbers
and the compiler should use a default block for unhandled states right?
Is code like call->marshall++ a common style for kernel state machines?
Perhaps not.
Does it work?
Sure.
Is it obvious what the transitions are?
No.
> All the other cases in the switch fall through.
>
> I would also generally prefer that the fallthrough statement occur before the
> blank line, not after it, since it belongs with the previous clause, and not
> between a comment about a case statement and its associated case statement,
> i.e.:
>
> afs_extract_to_tmp(call);
> call->unmarshall++;
>
> /* extract the callback array and its count in two steps */
> fallthrough;
> case 3:
>
> would be better written as:
>
> afs_extract_to_tmp(call);
> call->unmarshall++;
> fallthrough;
>
> /* extract the callback array and its count in two steps */
> case 3:
I agree completely.
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