On Thu, Apr 26, 2018 at 04:52:39PM +0300, Kirill Tkhai wrote: > In the patch I used the logic, that the below code: > > x = A; > spin_lock(); > spin_unlock(); > spin_lock(); > spin_unlock(); > y = B; > > cannot reorder much than: > > spin_lock(); > x = A; <- this can't become visible later, that spin_unlock() > spin_unlock(); > spin_lock(); > y = B; <- this can't become visible earlier, than spin_lock() > spin_unlock(); > > Is there a problem?
The two stores will be ordered, but only at the strength of an smp_wmb(). The above construct does not imply smp_mb(). The difference is observable on real hardware (Power).
