On Thu, Jun 02, 2016 at 12:44:51PM +0200, Arnd Bergmann wrote: > On Thursday, June 2, 2016 6:09:08 PM CEST Pan Xinhui wrote: > > diff --git a/include/asm-generic/qrwlock.h b/include/asm-generic/qrwlock.h > > index 54a8e65..eadd7a3 100644 > > --- a/include/asm-generic/qrwlock.h > > +++ b/include/asm-generic/qrwlock.h > > @@ -139,7 +139,7 @@ static inline void queued_read_unlock(struct qrwlock *lock) > > */ > > static inline void queued_write_unlock(struct qrwlock *lock) > > { > > - smp_store_release((u8 *)&lock->cnts, 0); > > + (void)atomic_sub_return_release(_QW_LOCKED, &lock->cnts); > > } > > Isn't this more expensive than the existing version? Yes, loads. And while this might be a suitable fix for asm-generic, it will introduce a fairly large regression on x86 (which is currently the only user of this). -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html