From: Frank Blaschka <frank.blaschka@de.ibm.com>
Date: Tue, 1 Apr 2008 08:26:59 +0000 (+0200)
Subject: qeth: core code should alloc headroom for LLC protocol
X-Git-Tag: firefly_0821_release~21615^2~8^2~13
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=b403e685b7c57f7912bae36987433e72c616f418;p=firefly-linux-kernel-4.4.55.git

qeth: core code should alloc headroom for LLC protocol

Allocate headroom for TR_HLEN but using only ETH_HLEN causes rx
performance degradation. Allocate ETH_HLEN for ethernet and
TR_HLEN for token ring (layer 3 mode).

Signed-off-by: Frank Blaschka <frank.blaschka@de.ibm.com>
Signed-off-by: Jeff Garzik <jgarzik@redhat.com>
---

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 5cfe0ef7719a..055f5c3e7b56 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -4002,7 +4002,11 @@ struct sk_buff *qeth_core_get_next_skb(struct qeth_card *card,
 		}
 	} else {
 		skb_len = (*hdr)->hdr.l3.length;
-		headroom = max((int)ETH_HLEN, (int)TR_HLEN);
+		if ((card->info.link_type == QETH_LINK_TYPE_LANE_TR) ||
+		    (card->info.link_type == QETH_LINK_TYPE_HSTR))
+			headroom = TR_HLEN;
+		else
+			headroom = ETH_HLEN;
 	}
 
 	if (!skb_len)