Re: [PATCH v2] kernel.h: handle pointers to arrays better in container_of()

[Ian Abbott]

On 23/05/17 12:24, Peter Zijlstra wrote:
> On Tue, May 23, 2017 at 11:32:02AM +0100, Ian Abbott wrote:
>
> > > #define container_of(ptr, type, member) (				\
> > > 	_Static_assert(__builtin_types_compatible_p(			\
> > >             typeof(*ptr), typeof( ((type *)0)->member )), "WUT"),	\
> > > 	((type *)((char *)(ptr) - offsetof(type, member)));		\
> > > )
> >
> > It's a fine suggestion (if more parentheses are added), but _Static_assert
> > is a C11 feature, and I thought the kernel was using gnu89 (unless it's been
> > updated since).
>
> We have BUILD_BUG_ON() that should be similar in functionality.

Yes, I think BUILD_BUG_ON_ZERO() will be better in this case to avoid 
some baggage.  Also, __same_type() can be used for type checking.

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