Re: [RFC PATCH 7/8] locking/barriers: Use '__unqual_scalar_typeof' for load-acquire macros

[Arnd Bergmann]

On Fri, Jan 10, 2020 at 5:57 PM Will Deacon <will@xxxxxxxxxx> wrote:

> @@ -128,10 +128,10 @@ do {                                                                      \
>  #ifndef __smp_load_acquire
>  #define __smp_load_acquire(p)                                          \
>  ({                                                                     \
> -       typeof(*p) ___p1 = READ_ONCE(*p);                               \
> +       __unqual_scalar_typeof(*p) ___p1 = READ_ONCE(*p);               \
>         compiletime_assert_atomic_type(*p);                             \
>         __smp_mb();                                                     \
> -       ___p1;                                                          \
> +       (typeof(*p))___p1;                                              \
>  })

Doesn't that last  (typeof(*p))___p1 mean you put the potential
'volatile' back on the assignment after you went through the
effort of taking it out?

       Arnd