From 2b567320de8c1b67c386a8b42165ca124a7bcca8 Mon Sep 17 00:00:00 2001
From: Samy Al Bahra <sbahra@appnexus.com>
Date: Thu, 17 Apr 2014 14:05:15 -0400
Subject: [PATCH] ck_rwlock: Acquire semantics for ordering on  latch bits.

---
 include/ck_rwlock.h | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/ck_rwlock.h b/include/ck_rwlock.h
index 5470b05..66b12f2 100644
--- a/include/ck_rwlock.h
+++ b/include/ck_rwlock.h
@@ -222,6 +222,7 @@ ck_rwlock_read_lock(ck_rwlock_t *rw)
 			 * fence operation. If writer is observed to 0, then
 			 * it is guaranteed that the latch will be visible.
 			 */
+			ck_pr_fence_load();
 			snapshot = ck_pr_load_32(&rw->n_readers);
 			if (snapshot >> CK_RWLOCK_LATCH_SHIFT)
 				continue;
@@ -232,8 +233,6 @@ ck_rwlock_read_lock(ck_rwlock_t *rw)
 		ck_pr_dec_32(&rw->n_readers);
 	}
 
-	/* Acquire semantics are necessary. */
-	ck_pr_fence_load();
 	return;
 }