On 11/05/2013 04:55 AM, Paul E. McKenney wrote: > On Mon, Nov 04, 2013 at 10:36:17PM +0200, Michael S. Tsirkin wrote: >> srcu read lock/unlock include a full memory barrier >> but that's an implementation detail. >> Add an API for make memory fencing explicit for >> users that need this barrier, to make sure we >> can change it as needed without breaking all users. >> >> Acked-by: "Paul E. McKenney" <[email protected]> >> Signed-off-by: Michael S. Tsirkin <[email protected]> > > Reviewed-by: Paul E. McKenney <[email protected]>
Acked-by: "Lai Jiangshan" <[email protected]> > >> --- >> include/linux/srcu.h | 14 ++++++++++++++ >> 1 file changed, 14 insertions(+) >> >> diff --git a/include/linux/srcu.h b/include/linux/srcu.h >> index c114614..9b058ee 100644 >> --- a/include/linux/srcu.h >> +++ b/include/linux/srcu.h >> @@ -237,4 +237,18 @@ static inline void srcu_read_unlock(struct srcu_struct >> *sp, int idx) >> __srcu_read_unlock(sp, idx); >> } >> >> +/** >> + * smp_mb__after_srcu_read_unlock - ensure full ordering after >> srcu_read_unlock >> + * >> + * Converts the preceding srcu_read_unlock into a two-way memory barrier. >> + * >> + * Call this after srcu_read_unlock, to guarantee that all memory operations >> + * that occur after smp_mb__after_srcu_read_unlock will appear to happen >> after >> + * the preceding srcu_read_unlock. >> + */ >> +static inline void smp_mb__after_srcu_read_unlock(void) >> +{ >> + /* __srcu_read_unlock has smp_mb() internally so nothing to do here. */ >> +} >> + >> #endif >> -- >> MST >> > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to [email protected] > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
