diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index eae270d81808..2dd46a05fb30 100644
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -1039,7 +1039,7 @@ err_out:
 /* Modular subtraction in ring */
 static inline int tx_dist(unsigned tail, unsigned head)
 {
-	return (head >= tail ? head : head + TX_RING_SIZE) - tail;
+	return (head - tail) % TX_RING_SIZE;
 }
 
 /* Number of list elements available for next tx */