On Sun, 12 Oct 2014, Qiaowei Ren wrote: > + /* > + * Go poke the address of the new bounds table in to the > + * bounds directory entry out in userspace memory. Note: > + * we may race with another CPU instantiating the same table. > + * In that case the cmpxchg will see an unexpected > + * 'actual_old_val'. > + */ > + ret = user_atomic_cmpxchg_inatomic(&actual_old_val, bd_entry, > + expected_old_val, bt_addr); This is fully preemptible non-atomic context, right? So this wants a proper comment, why using user_atomic_cmpxchg_inatomic() is the right thing to do here. Thanks, tglx
