On Mon, Mar 11, 2019 at 03:20:04PM +0100, Arnd Bergmann wrote: > On Mon, Mar 11, 2019 at 3:00 PM Qian Cai <cai@xxxxxx> wrote: > > > > On Mon, 2019-03-11 at 12:21 +0000, Jason Gunthorpe wrote: > > > On Sun, Mar 10, 2019 at 08:58:15PM -0700, Davidlohr Bueso wrote: > > > > On Sun, 10 Mar 2019, Qian Cai wrote: > > > > > > 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. s64 if anything, atomic stuff is signed (although since we have -fwrapv it doesn't matter one whit). > > A bit of history here, > > > > https://patchwork.kernel.org/patch/7344011/#15495901 > > Ah, I had already forgotten about that discussion. > > At least the atomic_long part we discussed there has been resolved now > as part of commit b5d47ef9ea5c ("locking/atomics: Switch to generated > atomic-long"). > > Adding Mark Rutland to Cc, maybe he has some ideas of how to use > the infrastructure he added to use consistent types for atomic64() > on the remaining 64-bit architectures. A quick count shows there's only 5 definitions of atomic64_t in the tree, it would be trivial to align them on type. $ git grep "} atomic64_t" arch/arc/include/asm/atomic.h:} atomic64_t; arch/arm/include/asm/atomic.h:} atomic64_t; arch/x86/include/asm/atomic64_32.h:} atomic64_t; include/asm-generic/atomic64.h:} atomic64_t; include/linux/types.h:} atomic64_t; Note that the one used in _most_ cases, is the one from linux/types.h, and that is using 'long'. The others, all typically on ILP32 platforms, obviously must use long long. I have no objection to changing the types.h one to long long or all of them to s64. It really shouldn't matter at all.
