Le mardi 10 mai 2011 à 12:18 -0700, john stultz a écrit : > So does something like this look better? I'm really not that familiar > with how ACCESS_ONCE is to be used, so forgive me if I'm not using it > correctly. > > Signed-off-by: John Stultz <[email protected]> > > Index: linux-2.6.32.y/kernel/time/timekeeping.c > =================================================================== > --- linux-2.6.32.y.orig/kernel/time/timekeeping.c 2011-05-04 > 19:34:21.604314152 -0700 > +++ linux-2.6.32.y/kernel/time/timekeeping.c 2011-05-10 12:15:48.756236916 > -0700 > @@ -168,8 +168,15 @@ int __read_mostly timekeeping_suspended; > static struct timespec xtime_cache __attribute__ ((aligned (16))); > void update_xtime_cache(u64 nsec) > { > - xtime_cache = xtime; > - timespec_add_ns(&xtime_cache, nsec); > + /* > + * Use temporary variable so get_seconds() cannot catch > + * an intermediate xtime_cache.tv_sec value. > + * The ACCESS_ONCE() keeps the compiler from optimizing > + * out the intermediate value. > + */ > + struct timespec ts = xtime; > + timespec_add_ns(&ts, nsec); > + ACCESS_ONCE(xtime_cache) = ts; > } > > /* must hold xtime_lock */ > >
Yes code looks good, please free to add my Acked-by: Eric Dumazet <[email protected]> Thanks _______________________________________________ stable mailing list [email protected] http://linux.kernel.org/mailman/listinfo/stable
