On Tuesday 28 May 2013, H. Peter Anvin wrote:

On 05/28/2013 08:43 AM, Arnd Bergmann wrote:

quoted

Right, that is what the patch I just posted does.

On a related note, I found that WARN_ON() can no longer be compiled
out since there is already code that relies on the side-effects of
the condition. I assume that was an intentional change I missed,
since it used to be defined so that you could remove it completely.

It is possible to define WARN_ON() as:

#define WARN_ON(x) ((void)(x))

... which preserves side effects.

Yes, actually the return value has to be maintained as well.
The current (!CONFIG_BUG) default implementation is

#define WARN_ON(condition) ({                                           \
        int __ret_warn_on = !!(condition);                              \
        unlikely(__ret_warn_on);                                        \
})

which seems fine.

#define WARN_ON(condition) unlikely(!!(condition))

is probably just as good.

	Arnd