Re: [PATCH v4 1/2] sunrpc: fix unused variable warnings by using no_printk

[Andrew Lunn]

> >  # define ifdebug(fac)		if (0)
> > -# define dfprintk(fac, fmt, ...)	do {} while (0)
> > -# define dfprintk_rcu(fac, fmt, ...)	do {} while (0)
> > +# define dfprintk(fac, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
> > +# define dfprintk_rcu(fac, fmt, ...)	no_printk(fmt, ##__VA_ARGS__)
> 
> You can omit fmt, then you don't need the ##
> #define dfprintk(fac, ...)	no_printk(__VA_ARGS__)

/*
 * Dummy printk for disabled debugging statements to use whilst maintaining
 * gcc's format checking.
 */
#define no_printk(fmt, ...)				\
({							\
	if (0)						\
		_printk(fmt, ##__VA_ARGS__);		\
	0;						\
})

Without fmt, gcc cannot do format checking. Or worse, it takes the
first member of __VA_ARGS__ as the format, and gives spurious errors?

      Andrew