On Mon, Aug 22, 2016 at 11:48:53AM -0700, Eric Dumazet wrote: > On Mon, Aug 22, 2016 at 10:34 AM, Paul E. McKenney > <[email protected]> wrote: > > > That does have much to say for itself, though I would prefer sizeof(void > > *) to sizeof(unsigned long). But would it make sense to define a mask > > on a per-architecture basis, with the default being (sizeof(void *) - 1)? > > Then maybe an IMPROPERLY_ALIGNED_POINTER(): > > > > #ifndef CONFIG_ARCH_POINTER_ALIGNMENT > > #define CONFIG_ARCH_POINTER_ALIGNMENT (sizeof(void *) - 1) > > #endif > > > > #define IMPROPERLY_ALIGNED_POINTER(p) \ > > ((p) & CONFIG_ARCH_POINTER_ALIGNMENT) > > > > m68k would define ARCH_POINTER_ALIGNMENT to 1, and all other arches > > would leave it undefined. > > > > Then __call_rcu() could to this: > > > > WARN_ON_ONCE(IMPROPERLY_ALIGNED_POINTER(head)); > > Don't we have __alignof__(void *) to avoid #ifdef CONFIG_M68K and > other new macros ?
Yes, but that 'hides' the m68k funny, while doing an explicit #ifdef has documentation value... but I don't care too deeply.
