From: Paolo Abeni <pabeni@redhat.com>
Date: Mon, 13 Jun 2016 22:00:04 +0000 (+0200)
Subject: tun: fix csum generation for tap devices
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=df10db98ab546e899b79d1b2b8a00a86fe8bb29d;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

tun: fix csum generation for tap devices

The commit 34166093639b ("tuntap: use common code for virtio_net_hdr
and skb GSO conversion") replaced the tun code for header manipulation
with the generic helpers. While doing so, it implictly moved the
skb_partial_csum_set() invocation after eth_type_trans(), which
invalidate the current gso start/offset values.
Fix it by moving the helper invocation before the mac pulling.

Fixes: 34166093639 ("tuntap: use common code for virtio_net_hdr and skb GSO conversion")
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Acked-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
---

diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 8cc6bf4f5ba3..4884802e0af1 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1254,6 +1254,13 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 		return -EFAULT;
 	}
 
+	err = virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun));
+	if (err) {
+		this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
+		kfree_skb(skb);
+		return -EINVAL;
+	}
+
 	switch (tun->flags & TUN_TYPE_MASK) {
 	case IFF_TUN:
 		if (tun->flags & IFF_NO_PI) {
@@ -1280,13 +1287,6 @@ static ssize_t tun_get_user(struct tun_struct *tun, struct tun_file *tfile,
 		break;
 	}
 
-	err = virtio_net_hdr_to_skb(skb, &gso, tun_is_little_endian(tun));
-	if (err) {
-		this_cpu_inc(tun->pcpu_stats->rx_frame_errors);
-		kfree_skb(skb);
-		return -EINVAL;
-	}
-
 	/* copy skb_ubuf_info for callback when skb has no error */
 	if (zerocopy) {
 		skb_shinfo(skb)->destructor_arg = msg_control;