commit 8fc54f68919298ff9689d980efb495707ef43f30
author Daniel Borkmann <dborkman@redhat.com> Sat Aug 23 20:58:54 2014 +0200
committer David S. Miller <davem@davemloft.net> Sat Aug 23 12:21:21 2014 -0700
tree c8a0c89621a9e670be02764a357bb6e73ed7ab6c
parent 690e36e726d00d2528bc569809048adf61550d80

net: use reciprocal_scale() helper

Replace open codings of (((u64) <x> * <y>) >> 32) with reciprocal_scale().

Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
Cc: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/core/dev.c

diff --git a/net/core/dev.c b/net/core/dev.c
index b65a505..1421dad 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -3124,8 +3124,7 @@
 	}
 
 	if (map) {
-		tcpu = map->cpus[((u64) hash * map->len) >> 32];
-
+		tcpu = map->cpus[reciprocal_scale(hash, map->len)];
 		if (cpu_online(tcpu)) {
 			cpu = tcpu;
 			goto done;

net/core/flow_dissector.c

diff --git a/net/core/flow_dissector.c b/net/core/flow_dissector.c
index 660c649..8ffcc97 100644
--- a/net/core/flow_dissector.c
+++ b/net/core/flow_dissector.c
@@ -298,7 +298,7 @@
 		qcount = dev->tc_to_txq[tc].count;
 	}
 
-	return (u16) (((u64)skb_get_hash(skb) * qcount) >> 32) + qoffset;
+	return (u16) reciprocal_scale(skb_get_hash(skb), qcount) + qoffset;
 }
 EXPORT_SYMBOL(__skb_tx_hash);
 
@@ -371,9 +371,8 @@
 			if (map->len == 1)
 				queue_index = map->queues[0];
 			else
-				queue_index = map->queues[
-				    ((u64)skb_get_hash(skb) * map->len) >> 32];
-
+				queue_index = map->queues[reciprocal_scale(skb_get_hash(skb),
+									   map->len)];
 			if (unlikely(queue_index >= dev->real_num_tx_queues))
 				queue_index = -1;
 		}