Subject: [PATCH 19/32] net: fix harmonize_features() vs NETIF_F_HIGHDMA

From: Eric Dumazet <[email-masked]>
Date: Wed, 18 Jan 2017 12:12:17 -0800

[ 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 <[email-masked]>
Cc: Pravin Shelar <[email-masked]>
Reported-by: "Ashizuka, Yuusuke" <[email-masked]>
Signed-off-by: David S. Miller <[email-masked]>
---
 net/core/dev.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/core/dev.c b/net/core/dev.c
index e1d731f..df51c50 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -2815,9 +2815,9 @@ static netdev_features_t harmonize_features(struct sk_buff *skb,
 	if (skb->ip_summed != CHECKSUM_NONE &&
 	    !can_checksum_protocol(features, type)) {
 		features &= ~(NETIF_F_CSUM_MASK | NETIF_F_GSO_MASK);
-	} else if (illegal_highdma(skb->dev, skb)) {
-		features &= ~NETIF_F_SG;
 	}
+	if (illegal_highdma(skb->dev, skb))
+		features &= ~NETIF_F_SG;
 
 	return features;
 }
-- 
2.4.11