[PATCH] sky2: ring distance optimization

Faster way to compute ring distance.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index eae270d..2dd46a0 100644 (file)
--- 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 */