Re: [PATCH 2/2] mdadm.c: fix compile error "switch condition has boolean value"

[Jes Sorensen]

On 03/30/2017 03:52 AM, Gioh Kim wrote:
> On Thu, Mar 30, 2017 at 08:38:35AM +1100, NeilBrown wrote:
> > On Thu, Mar 30 2017, jes.sorensen@xxxxxxxxx wrote:
> >
> > > Gioh Kim <gi-oh.kim@xxxxxxxxxxxxxxxx> writes:
> > > > Remove a boolean expression in switch condition
> > > > to prevent compile error of some compilers.
> > >
> > > Please be specific, which compile is unable to handle this?
> > >
> > > > Signed-off-by: Gioh Kim <gi-oh.kim@xxxxxxxxxxxxxxxx>
> > > > ---
> > > >  mdadm.c | 6 +++---
> > > >  1 file changed, 3 insertions(+), 3 deletions(-)
> > > >
> > > > diff --git a/mdadm.c b/mdadm.c
> > > > index 08ddcab..a98a051 100644
> > > > --- a/mdadm.c
> > > > +++ b/mdadm.c
> > > > @@ -1905,11 +1905,11 @@ static int misc_list(struct mddev_dev *devlist,
> > > >  			rv |= SetAction(dv->devname, c->action);
> > > >  			continue;
> > > >  		}
> > > > -		switch(dv->devname[0] == '/') {
> > > > -			case 0:
> > > > +		switch(dv->devname[0]) {
> > > > +			default:
> > > >  				mdfd = open_dev(dv->devname);
> > > >  				if (mdfd >= 0) break;
> > > > -			case 1:
> > > > +			case '/':
> > > >  				mdfd = open_mddev(dv->devname, 1);
> > > >  		}
> > > >  		if (mdfd>=0) {
> > >
> > > While I agree the original code is ugly, I am not convinced your
> > > replacement is a lot prettier.
> >
> > Maybe
> >
> > 		if (dv->devname[0] == '/' ||
> > 		    (mdfd = open_dev(dv->devname)) < 0)
> > 				mdfd = open_mddev(dv->devname, 1);
> >
> > ??
> > NeilBrown
>
> Yes, the initial version I thought was:
>
> if (dev->devname[0] != '/')
>     mdfd = open_dev(dv->devname);
> if (dev->devname[0] == '/' || mdfd < 0)
>     mdfd = open_mddev(dv->devname, 1);
>
> But I thought you have a reason to use switch-case expression,
> so I kept switch-case.
> If you agree, I'll send v2 patch using if-expression.

I like this solution better, I much favor code that is more explicit in 
what it does. Request less brain capacity for me to read :)

Cheers,
Jes