On Tue, Jun 05, 2018 at 11:26:37AM +0200, Peter Zijlstra wrote: > On Tue, May 29, 2018 at 04:43:35PM +0100, Mark Rutland wrote: > > /** > > + * atomic64_add_unless - add unless the number is already a given value > > + * @v: pointer of type atomic_t > > + * @a: the amount to add to v... > > + * @u: ...unless v is equal to u. > > + * > > + * Atomically adds @a to @v, so long as @v was not already @u. > > + * Returns non-zero if @v was not @u, and zero otherwise. > > I always get confused by that wording; would something like: "Returns > true if the addition was done" not be more clear?
Sounds clearer to me; I just stole the wording from the existing atomic_add_unless(). I guess you'll want similar for the conditional inc/dec ops, e.g. /** * atomic_inc_not_zero - increment unless the number is zero * @v: pointer of type atomic_t * * Atomically increments @v by 1, so long as @v is non-zero. * Returns non-zero if @v was non-zero, and zero otherwise. */ > > + */ > > +#ifdef atomic64_fetch_add_unless > > +static inline int atomic64_add_unless(atomic64_t *v, long long a, long > > long u) > > Do we want to make that a "bool' return? I think so -- that's what the instrumented wrappers (and x86) do today anyhow, and what I ended up using for the generated headers. I'll spin a prep patch cleaning up the existing fallbacks in <linux/atomic.h>, along with the comment fixup above, then rework the additions likewise. Thanks, Mark.
