From ec7abebc0b4707991dc1485b9332e2bd338bc4a3 Mon Sep 17 00:00:00 2001
From: jD91mZM2 <me@krake.one>
Date: Thu, 27 Jun 2019 07:16:52 +0200
Subject: [PATCH] Fix a very slight error in the mutex
This was just my attempt at being smart, I didn't realize
`compare_exchange` returned the old value (I'm dumb!), so I thought
that if the value was 1 then it must have become 2. Normally with
small errors like these you should leave a comment explaining why, but
really, compare and *exchange* is pretty obvious. My bad.
---
src/mutex.rs | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/src/mutex.rs b/src/mutex.rs
index 2c7d52a53..3e3d5df22 100644
--- a/src/mutex.rs
+++ b/src/mutex.rs
@@ -70,7 +70,7 @@ impl<T> Mutex<T> {
//
// - Skip the atomic operation if the last value was 2, since it most likely hasn't changed.
// - Skip the futex wait if the atomic operation says the mutex is unlocked.
- if last == 2 || self.atomic().compare_exchange(1, 2, SeqCst, SeqCst).unwrap_or_else(|err| err) == 2 {
+ if last == 2 || self.atomic().compare_exchange(1, 2, SeqCst, SeqCst).unwrap_or_else(|err| err) != 0 {
Sys::futex(self.atomic().get_mut(), FUTEX_WAIT, 2);
}
--
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