Patch "virtio: don't set VIRTIO_NET_HDR_F_DATA_VALID on xmit" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

virtio: don't set VIRTIO_NET_HDR_F_DATA_VALID on xmit

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
virtio-don-t-set-virtio_net_hdr_f_data_valid-on-xmit.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Rolf Neugebauer <[email protected]>
Date: Tue, 17 Jan 2017 18:13:51 +0000
Subject: virtio: don't set VIRTIO_NET_HDR_F_DATA_VALID on xmit

From: Rolf Neugebauer <[email protected]>

[ Upstream commit 501db511397fd6efff3aa5b4e8de415b55559550 ]

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.

---
 include/linux/virtio_net.h |    2 --
 1 file changed, 2 deletions(-)

@@ -91,8 +91,6 @@ static inline int virtio_net_hdr_from_sk
 				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;

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/virtio-net-restore-virtio_hdr_f_data_valid-on-receiving.patch queue-4.9/virtio-don-t-set-virtio_net_hdr_f_data_valid-on-xmit.patch