PERFORCE change 126950 for review

[Kip Macy]

http://perforce.freebsd.org/chv.cgi?CH=126950

Change 126950 by kmacy at kmacy_home:ethng on 2007/09/29 05:20:19

	fix ring count to correctly account for prod < cons

Affected files ...

.. //depot/projects/ethng/src/sys/dev/cxgb/cxgb_osdep.h#11 edit

Differences ...

==== //depot/projects/ethng/src/sys/dev/cxgb/cxgb_osdep.h#11 (text+ko) ====

@@ -72,7 +72,10 @@
 static __inline int
 mbuf_ring_count(struct mbuf_ring *mr)
 {
-	return abs(mr->mr_cons - mr->mr_prod);
+	int size = mr->mr_size;
+	int mask = size - 1;
+	
+	return ((size + mr->mr_prod - mr->mr_cons) & mask);
 }
 
 static __inline int