On Tue, 03 Nov 2015, Sebastian Andrzej Siewior wrote:
In pipelined_receive() (mqueue) there is the wake_q_add() with the implicit cmpxchg barrier. The matching barrier pairing should be in wq_sleep() but there is none. Why is it okay to have none there and I need one here?
So the pairing in mqueue is done in wq_sleep() as we unlock info->lock, so there's an implied barrier there. Also, considering Peter's suggestion to wrap around READ/WRITE_ONCE for sysv queues (specially since you got rid of the volatile tag), it seems we also need them for mqueues. Thanks, Davidlohr -- 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/
