[ltt-dev] [PATCH] urcu_ref: do error checking on urcu_ref_put

[Paolo Bonzini]

Underflow is what you really want to trap.  When you reach urcu_ref_get, it
is already too late.

Signed-off-by: Paolo Bonzini <pbonzini at redhat.com>
---
 urcu/urcu_ref.h |    7 ++++---
 1 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/urcu/urcu_ref.h b/urcu/urcu_ref.h
index bce7116..06b81b9 100644
--- a/urcu/urcu_ref.h
+++ b/urcu/urcu_ref.h
@@ -33,14 +33,15 @@ static inline void urcu_ref_init(struct urcu_ref *ref)
 
 static inline void urcu_ref_get(struct urcu_ref *ref)
 {
-	long res = uatomic_add_return(&ref->refcount, 1);
-	assert(res != 0);
+	uatomic_add(&ref->refcount, 1);
 }
 
 static inline void urcu_ref_put(struct urcu_ref *ref,
 				void (*release)(struct urcu_ref *))
 {
-	if (!uatomic_sub_return(&ref->refcount, 1))
+        long res = uatomic_sub_return(&ref->refcount, 1);
+        assert (res >= 0);
+        if (res == 0)
 		release(ref);
 }
 
-- 
1.7.4.4