Messages in this thread | | | From | Arnd Bergmann <> | Date | Mon, 11 Mar 2019 15:00:50 +0100 | Subject | Re: [PATCH] mm/debug: add a cast to u64 for atomic64_read() |
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On Mon, Mar 11, 2019 at 1:21 PM Jason Gunthorpe <jgg@mellanox.com> wrote: > On Sun, Mar 10, 2019 at 08:58:15PM -0700, Davidlohr Bueso wrote: > > On Sun, 10 Mar 2019, Qian Cai wrote:
> > > > Acked-by: Davidlohr Bueso <dbueso@suse.de> > > Not saying this patch shouldn't go ahead.. > > But is there a special reason the atomic64*'s on ppc don't use the u64 > type like other archs? Seems like a better thing to fix than adding > casts all over the place.
Agreed in principle, but I'd note that it's not just ppc64, but almost all 64-bit architectures. x86-64 and arm64 changed over last year from returning 'long' to 'long long', apparently as an unintended side effect of commits 8bf705d13039 ("locking/atomic/x86: Switch atomic.h to use atomic-instrumented.h") and c0df10812835 ("arm64, locking/atomics: Use instrumented atomics").
It would be nice to just do the instrumented atomics on all 64-bit architectures for consistency, but that would be a lot of work, and would not actually give us additional instrumentation on most of them, since they don't support KASAN (except s390).
Arnd
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