[ 3.8.y.z extended stable ] Patch "r8169: fix offloaded tx checksum for small packets." has been added to staging queue

Kamal Mostafa kamal at canonical.com
Tue Jun 25 22:20:09 UTC 2013


This is a note to let you know that I have just added a patch titled

    r8169: fix offloaded tx checksum for small packets.

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.4.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

------

>From 5c56f9f11bf6818469541baee788682e614e55ed Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?fran=C3=A7ois=20romieu?= <romieu at fr.zoreil.com>
Date: Sat, 18 May 2013 01:24:46 +0000
Subject: r8169: fix offloaded tx checksum for small packets.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

[ Upstream commit b423e9ae49d78ea3f53b131c8d5a6087aed16fd6 ]

8168evl offloaded checksums are wrong since commit
e5195c1f31f399289347e043d6abf3ffa80f0005 ("r8169: fix 8168evl frame padding.")
pads small packets to 60 bytes (without ethernet checksum). Typical symptoms
appear as UDP checksums which are wrong by the count of added bytes.

It isn't worth compensating. Let the driver checksum.

Due to the skb length changes, TSO code is moved before the Tx descriptor gets
written.

Signed-off-by: Francois Romieu <romieu at fr.zoreil.com>
Tested-by: Holger Hoffstätte <holger.hoffstaette at googlemail.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
 drivers/net/ethernet/realtek/r8169.c | 41 ++++++++++++++++++++++++------------
 1 file changed, 27 insertions(+), 14 deletions(-)

diff --git a/drivers/net/ethernet/realtek/r8169.c b/drivers/net/ethernet/realtek/r8169.c
index b64315b..4fa28fe 100644
--- a/drivers/net/ethernet/realtek/r8169.c
+++ b/drivers/net/ethernet/realtek/r8169.c
@@ -5748,7 +5748,20 @@ err_out:
 	return -EIO;
 }

-static inline void rtl8169_tso_csum(struct rtl8169_private *tp,
+static bool rtl_skb_pad(struct sk_buff *skb)
+{
+	if (skb_padto(skb, ETH_ZLEN))
+		return false;
+	skb_put(skb, ETH_ZLEN - skb->len);
+	return true;
+}
+
+static bool rtl_test_hw_pad_bug(struct rtl8169_private *tp, struct sk_buff *skb)
+{
+	return skb->len < ETH_ZLEN && tp->mac_version == RTL_GIGA_MAC_VER_34;
+}
+
+static inline bool rtl8169_tso_csum(struct rtl8169_private *tp,
 				    struct sk_buff *skb, u32 *opts)
 {
 	const struct rtl_tx_desc_info *info = tx_desc_info + tp->txd_version;
@@ -5761,13 +5774,20 @@ static inline void rtl8169_tso_csum(struct rtl8169_private *tp,
 	} else if (skb->ip_summed == CHECKSUM_PARTIAL) {
 		const struct iphdr *ip = ip_hdr(skb);

+		if (unlikely(rtl_test_hw_pad_bug(tp, skb)))
+			return skb_checksum_help(skb) == 0 && rtl_skb_pad(skb);
+
 		if (ip->protocol == IPPROTO_TCP)
 			opts[offset] |= info->checksum.tcp;
 		else if (ip->protocol == IPPROTO_UDP)
 			opts[offset] |= info->checksum.udp;
 		else
 			WARN_ON_ONCE(1);
+	} else {
+		if (unlikely(rtl_test_hw_pad_bug(tp, skb)))
+			return rtl_skb_pad(skb);
 	}
+	return true;
 }

 static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
@@ -5788,17 +5808,15 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
 		goto err_stop_0;
 	}

-	/* 8168evl does not automatically pad to minimum length. */
-	if (unlikely(tp->mac_version == RTL_GIGA_MAC_VER_34 &&
-		     skb->len < ETH_ZLEN)) {
-		if (skb_padto(skb, ETH_ZLEN))
-			goto err_update_stats;
-		skb_put(skb, ETH_ZLEN - skb->len);
-	}
-
 	if (unlikely(le32_to_cpu(txd->opts1) & DescOwn))
 		goto err_stop_0;

+	opts[1] = cpu_to_le32(rtl8169_tx_vlan_tag(skb));
+	opts[0] = DescOwn;
+
+	if (!rtl8169_tso_csum(tp, skb, opts))
+		goto err_update_stats;
+
 	len = skb_headlen(skb);
 	mapping = dma_map_single(d, skb->data, len, DMA_TO_DEVICE);
 	if (unlikely(dma_mapping_error(d, mapping))) {
@@ -5810,11 +5828,6 @@ static netdev_tx_t rtl8169_start_xmit(struct sk_buff *skb,
 	tp->tx_skb[entry].len = len;
 	txd->addr = cpu_to_le64(mapping);

-	opts[1] = cpu_to_le32(rtl8169_tx_vlan_tag(skb));
-	opts[0] = DescOwn;
-
-	rtl8169_tso_csum(tp, skb, opts);
-
 	frags = rtl8169_xmit_frags(tp, skb, opts);
 	if (frags < 0)
 		goto err_dma_1;
--
1.8.1.2





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