Re: [PATCH] atomic.h: Reword confusing comment for qatomic_cmpxchg

[Jonathan Cameron via <qemu-devel@nongnu.org>]

On Fri, 23 Feb 2024 08:21:42 -1000
Richard Henderson <richard.henderson@linaro.org> wrote:

> On 2/23/24 08:20, Peter Maydell wrote:
> > The qatomic_cmpxchg() and qatomic_cmpxchg__nocheck() macros have
> > a comment that reads:
> >   Returns the eventual value, failed or not
> > 
> > This is somewhere between cryptic and wrong, since the value actually
> > returned is the value that was in memory before the cmpxchg.  Reword
> > to match how we describe these macros in atomics.rst.
> > 
> > Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> > ---
> >   include/qemu/atomic.h | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/include/qemu/atomic.h b/include/qemu/atomic.h
> > index f1d3d1702a9..99110abefb3 100644
> > --- a/include/qemu/atomic.h
> > +++ b/include/qemu/atomic.h
> > @@ -202,7 +202,7 @@
> >       qatomic_xchg__nocheck(ptr, i);                          \
> >   })
> >   
> > -/* Returns the eventual value, failed or not */
> > +/* Returns the old value of '*ptr' (whether the cmpxchg failed or not) */
> >   #define qatomic_cmpxchg__nocheck(ptr, old, new)    ({                   \
> >       typeof_strip_qual(*ptr) _old = (old);                               \
> >       (void)__atomic_compare_exchange_n(ptr, &_old, new, false,           \  
> 
> Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

As the person it confused ;)
> 
> r~