[23/70] net_sched: fix ip_tos2prio

[Greg KH]

2.6.38-stable review patch.  If anyone has any objections, please let us know.

------------------


From: Dan Siemon <dan@xxxxxxxxxxxxx>

[ Upstream commit 4a2b9c3756077c05dd8666e458a751d2248b61b6 ]

ECN support incorrectly maps ECN BESTEFFORT packets to TC_PRIO_FILLER
(1) instead of TC_PRIO_BESTEFFORT (0)

This means ECN enabled flows are placed in pfifo_fast/prio low priority
band, giving ECN enabled flows [ECT(0) and CE codepoints] higher drop
probabilities.

This is rather unfortunate, given we would like ECN being more widely
used.

Ref : http://www.coverfire.com/archives/2011/03/13/pfifo_fast-and-ecn/

Signed-off-by: Dan Siemon <dan@xxxxxxxxxxxxx>
Signed-off-by: Eric Dumazet <eric.dumazet@xxxxxxxxx>
Cc: Dave Täht <d@xxxxxxxx>
Cc: Jonathan Morton <chromatix99@xxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>
---
 net/ipv4/route.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -171,7 +171,7 @@ static struct dst_ops ipv4_dst_ops = {
 
 const __u8 ip_tos2prio[16] = {
 	TC_PRIO_BESTEFFORT,
-	ECN_OR_COST(FILLER),
+	ECN_OR_COST(BESTEFFORT),
 	TC_PRIO_BESTEFFORT,
 	ECN_OR_COST(BESTEFFORT),
 	TC_PRIO_BULK,


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