On Thu, Sep 01, 2016 at 04:30:39PM +0100, Will Deacon wrote: > On Thu, Sep 01, 2016 at 05:27:52PM +0200, Manfred Spraul wrote: > > Since spin_unlock_wait() is defined as equivalent to spin_lock(); > > spin_unlock(), the memory barrier before spin_unlock_wait() is > > also not required. Note that ACQUIRE+RELEASE isn't a barrier. Both are semi-permeable and things can cross in the middle, like: x = 1; LOCK UNLOCK r = y; can (validly) get re-ordered like: LOCK r = y; x = 1; UNLOCK So if you want things ordered, as I think you do, I think the smp_mb() is still needed. RELEASE + ACQUIRE otoh, that is a load-store barrier (but not transitive). -- To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
