Messages in this thread | | | Date | Thu, 23 May 2019 10:30:13 +0200 | From | Andrea Parri <> | Subject | Re: [PATCH 00/18] locking/atomic: atomic64 type cleanup |
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Hi Mark,
On Wed, May 22, 2019 at 02:22:32PM +0100, Mark Rutland wrote: > Currently architectures return inconsistent types for atomic64 ops. Some return > long (e..g. powerpc), some return long long (e.g. arc), and some return s64 > (e.g. x86).
(only partially related, but probably worth asking:)
While reading the series, I realized that the following expression:
atomic64_t v; ... typeof(v.counter) my_val = atomic64_set(&v, VAL);
is a valid expression on some architectures (in part., on architectures which #define atomic64_set() to WRITE_ONCE()) but is invalid on others. (This is due to the fact that WRITE_ONCE() can be used as an rvalue in the above assignment; TBH, I ignore the reasons for having such rvalue?)
IIUC, similar considerations hold for atomic_set().
The question is whether this is a known/"expected" inconsistency in the implementation of atomic64_set() or if this would also need to be fixed /addressed (say in a different patchset)?
Thanks, Andrea
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