ck_rwlock: Use ck_pr_fence_atomic.

include/ck_rwlock.h

@@ -74,7 +74,8 @@ ck_rwlock_write_trylock(ck_rwlock_t *rw)
 	if (ck_pr_fas_uint(&rw->writer, 1) != 0)
 		return false;
 
-	ck_pr_fence_memory();
+	ck_pr_fence_atomic_load();
+
 	if (ck_pr_load_uint(&rw->n_readers) != 0) {
 		ck_rwlock_write_unlock(rw);
 		return false;
@@ -90,7 +91,7 @@ ck_rwlock_write_lock(ck_rwlock_t *rw)
 	while (ck_pr_fas_uint(&rw->writer, 1) != 0)
 		ck_pr_stall();
 
-	ck_pr_fence_memory();
+	ck_pr_fence_atomic_load();
 
 	while (ck_pr_load_uint(&rw->n_readers) != 0)
 		ck_pr_stall();
@@ -111,16 +112,15 @@ ck_rwlock_read_trylock(ck_rwlock_t *rw)
 	 * Serialize with respect to concurrent write
 	 * lock operation.
 	 */
-	ck_pr_fence_memory();
-	if (ck_pr_load_uint(&rw->writer) == 0)
-		goto leave;
+	ck_pr_fence_atomic_load();
+
+	if (ck_pr_load_uint(&rw->writer) == 0) {
+		ck_pr_fence_load();
+		return true;
+	}
+
 	ck_pr_dec_uint(&rw->n_readers);
 	return false;
-
-leave:
-	/* Acquire semantics are necessary. */
-	ck_pr_fence_load();
-	return true;
 }
 
 CK_CC_INLINE static void
@@ -137,7 +137,8 @@ ck_rwlock_read_lock(ck_rwlock_t *rw)
 		 * Serialize with respect to concurrent write
 		 * lock operation.
 		 */
-		ck_pr_fence_memory();
+		ck_pr_fence_atomic_load();
+
 		if (ck_pr_load_uint(&rw->writer) == 0)
 			break;
 		ck_pr_dec_uint(&rw->n_readers);
@@ -180,7 +181,7 @@ ck_rwlock_recursive_write_lock(ck_rwlock_recursive_t *rw, unsigned int tid)
 	while (ck_pr_cas_uint(&rw->rw.writer, 0, tid) == false)
 		ck_pr_stall();
 
-	ck_pr_fence_memory();
+	ck_pr_fence_atomic_load();
 
 	while (ck_pr_load_uint(&rw->rw.n_readers) != 0)
 		ck_pr_stall();
@@ -202,7 +203,7 @@ ck_rwlock_recursive_write_trylock(ck_rwlock_recursive_t *rw, unsigned int tid)
 	if (ck_pr_cas_uint(&rw->rw.writer, 0, tid) == false)
 		return false;
 
-	ck_pr_fence_memory();
+	ck_pr_fence_atomic_load();
 
 	if (ck_pr_load_uint(&rw->rw.n_readers) != 0) {
 		ck_pr_store_uint(&rw->rw.writer, 0);