netdev - [PATCH] virtio: don't set VIRTIO_NET_HDR_F_DATA

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Message-Id: <20170117181351.98291-1-rolf.neugebauer@docker.com>
Date:   Tue, 17 Jan 2017 18:13:51 +0000
From:   Rolf Neugebauer <rolf.neugebauer@...ker.com>
To:     netdev@...r.kernel.org
Cc:     mst@...hat.com, davem@...emloft.net, jasowang@...hat.com,
        rppt@...ux.vnet.ibm.com,
        Rolf Neugebauer <rolf.neugebauer@...ker.com>
Subject: [PATCH] virtio: don't set VIRTIO_NET_HDR_F_DATA_VALID on xmit

This patch part reverts fd2a0437dc33 and e858fae2b0b8 which introduced a
subtle change in how the virtio_net flags are derived from the SKBs
ip_summed field.

With the above commits, the flags are set to VIRTIO_NET_HDR_F_DATA_VALID
when ip_summed == CHECKSUM_UNNECESSARY, thus treating it differently to
ip_summed == CHECKSUM_NONE, which should be the same.

Further, the virtio spec 1.0 / CS04 explicitly says that
VIRTIO_NET_HDR_F_DATA_VALID must not be set by the driver.

Signed-off-by: Rolf Neugebauer <rolf.neugebauer@...ker.com>
---
 include/linux/virtio_net.h | 2 --
 1 file changed, 2 deletions(-)

diff --git a/include/linux/virtio_net.h b/include/linux/virtio_net.h
index 66204007d7ac..56436472ccc7 100644
--- a/include/linux/virtio_net.h
+++ b/include/linux/virtio_net.h
@@ -91,8 +91,6 @@ static inline int virtio_net_hdr_from_skb(const struct sk_buff *skb,
 				skb_checksum_start_offset(skb));
 		hdr->csum_offset = __cpu_to_virtio16(little_endian,
 				skb->csum_offset);
-	} else if (skb->ip_summed == CHECKSUM_UNNECESSARY) {
-		hdr->flags = VIRTIO_NET_HDR_F_DATA_VALID;
 	} /* else everything is zero */

 	return 0;
-- 
2.11.0