From: Stephen Hemminger <shemminger@osdl.org>
Date: Fri, 9 Dec 2005 19:34:59 +0000 (-0800)
Subject: [PATCH] sky2: ring distance optimization
X-Git-Tag: v2.6.16-rc1~474^2~22^2~7^2~35
X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=129372d0524c9124d5693f63c1d3c1ce2e3714ce;p=linux-2.6

[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 eae270d818..2dd46a05fb 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 */