From: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Date: Wed, 10 Nov 2010 13:03:15 +0000 (-0800)
Subject: ath9k: Fix bug in delimiter padding computation
X-Git-Tag: v2.6.34.10~220
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=ed6b4a0dd9707ac22620feecbe5a87585806ca29;p=karo-tx-linux.git

ath9k: Fix bug in delimiter padding computation

commit 39ec2997c374b528cdbf65099b6d6b8593a67f7f upstream.

There is a roundng error in delimiter padding computation
which causes severe throughput drop with some of AR9003.

signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Vasanthakumar Thiagarajan <vasanth@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---

diff --git a/drivers/net/wireless/ath/ath9k/ath9k.h b/drivers/net/wireless/ath/ath9k/ath9k.h
index 83c7ea4c007f..7f367315977d 100644
--- a/drivers/net/wireless/ath/ath9k/ath9k.h
+++ b/drivers/net/wireless/ath/ath9k/ath9k.h
@@ -172,8 +172,8 @@ void ath_descdma_cleanup(struct ath_softc *sc, struct ath_descdma *dd,
 
 /* returns delimiter padding required given the packet length */
 #define ATH_AGGR_GET_NDELIM(_len)					\
-	(((((_len) + ATH_AGGR_DELIM_SZ) < ATH_AGGR_MINPLEN) ?           \
-	  (ATH_AGGR_MINPLEN - (_len) - ATH_AGGR_DELIM_SZ) : 0) >> 2)
+       (((_len) >= ATH_AGGR_MINPLEN) ? 0 :                             \
+        DIV_ROUND_UP(ATH_AGGR_MINPLEN - (_len), ATH_AGGR_DELIM_SZ))
 
 #define BAW_WITHIN(_start, _bawsz, _seqno) \
 	((((_seqno) - (_start)) & 4095) < (_bawsz))