io: avoid unnecessary wake in registration (#2221)

See discussion in #2222. This wake/notify call has been there in one
form or another since the very early days of tokio. Currently though, it
is not clear that it is needed; the contract for polling is that you
must keep polling until you get `Pending`, so doing a wakeup when we are
about to return `Ready` is premature.

1 files changed, 1 insertions, 0 deletions

diff --git a/tokio/src/util/bit.rs b/tokio/src/util/bit.rs
index d18298f7..e61ac216 100644
--- a/tokio/src/util/bit.rs
+++ b/tokio/src/util/bit.rs
@@ -33,6 +33,7 @@ impl Pack {
     }
 
     /// Mask used to unpack value
+    #[cfg(all(test, loom))]
     pub(crate) const fn mask(&self) -> usize {
         self.mask
     }