From: Eric Dumazet <edumazet@google.com>
Date: Wed, 18 Jan 2017 20:12:17 +0000 (-0800)
Subject: net: fix harmonize_features() vs NETIF_F_HIGHDMA
X-Git-Tag: v3.12.71~97
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c00bb94dc37732ff4aac6567a2694ac9d0ac5e45;p=thirdparty%2Fkernel%2Fstable.git

net: fix harmonize_features() vs NETIF_F_HIGHDMA

[ Upstream commit 7be2c82cfd5d28d7adb66821a992604eb6dd112e ]

Ashizuka reported a highmem oddity and sent a patch for freescale
fec driver.

But the problem root cause is that core networking stack
must ensure no skb with highmem fragment is ever sent through
a device that does not assert NETIF_F_HIGHDMA in its features.

We need to call illegal_highdma() from harmonize_features()
regardless of CSUM checks.

Fixes: ec5f06156423 ("net: Kill link between CSUM and SG features.")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: Pravin Shelar <pshelar@ovn.org>
Reported-by: "Ashizuka, Yuusuke" <ashiduka@jp.fujitsu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---

diff --git a/net/core/dev.c b/net/core/dev.c
index 6b0ddf661f924..b35fcebc52b8b 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2489,9 +2489,9 @@ static netdev_features_t harmonize_features(struct sk_buff *skb,
 	if (skb->ip_summed != CHECKSUM_NONE &&
 	    !can_checksum_protocol(features, skb_network_protocol(skb))) {
 		features &= ~NETIF_F_ALL_CSUM;
-	} else if (illegal_highdma(dev, skb)) {
-		features &= ~NETIF_F_SG;
 	}
+	if (illegal_highdma(dev, skb))
+		features &= ~NETIF_F_SG;
 
 	return features;
 }