[PATCH net] hyperv: Fix vlan_proto setting in netvsc_recv_callback()

[PATCH net] hyperv: Fix vlan_proto setting in netvsc_recv_callback()

[Haiyang Zhang]

Since the recent addition of 8021AD, we need to set the new field vlan_proto in
sk_buff. Otherwise, it will trigger BUG() call in vlan_proto_idx().

This patch fixes the problem.

Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>

---
 drivers/net/hyperv/netvsc_drv.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)

diff --git a/drivers/net/hyperv/netvsc_drv.c b/drivers/net/hyperv/netvsc_drv.c
index 088c554..ab2307b 100644
--- a/drivers/net/hyperv/netvsc_drv.c
+++ b/drivers/net/hyperv/netvsc_drv.c
@@ -31,6 +31,7 @@
 #include <linux/inetdevice.h>
 #include <linux/etherdevice.h>
 #include <linux/skbuff.h>
+#include <linux/if_vlan.h>
 #include <linux/in.h>
 #include <linux/slab.h>
 #include <net/arp.h>
@@ -284,7 +285,7 @@ int netvsc_recv_callback(struct hv_device *device_obj,
 
 	skb->protocol = eth_type_trans(skb, net);
 	skb->ip_summed = CHECKSUM_NONE;
-	skb->vlan_tci = packet->vlan_tci;
+	__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), packet->vlan_tci);
 
 	net->stats.rx_packets++;
 	net->stats.rx_bytes += packet->total_data_buflen;
-- 
1.7.4.1

Re: [PATCH net] hyperv: Fix vlan_proto setting in netvsc_recv_callback()

[David Miller]

From: Haiyang Zhang <haiyangz@microsoft.com>
Date: Tue, 28 May 2013 09:15:56 -0700

> Since the recent addition of 8021AD, we need to set the new field vlan_proto in
> sk_buff. Otherwise, it will trigger BUG() call in vlan_proto_idx().
> 
> This patch fixes the problem.
> 
> Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
> Reviewed-by: K. Y. Srinivasan <kys@microsoft.com>

Applied, thanks.

Re: [PATCH net] hyperv: Fix vlan_proto setting in netvsc_recv_callback()

[Olaf Hering]

On Tue, May 28, Haiyang Zhang wrote:

> Since the recent addition of 8021AD, we need to set the new field vlan_proto in
> sk_buff. Otherwise, it will trigger BUG() call in vlan_proto_idx().

> @@ -284,7 +285,7 @@ int netvsc_recv_callback(struct hv_device *device_obj,
>  
>  	skb->protocol = eth_type_trans(skb, net);
>  	skb->ip_summed = CHECKSUM_NONE;
> -	skb->vlan_tci = packet->vlan_tci;
> +	__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), packet->vlan_tci);


Just curious:

Doesnt that change behaviour in the sense that __vlan_hwaccel_put_tag()
now always adds VLAN_TAG_PRESENT to skb->vlan_tci, while before that
change packet->vlan_tci may or may not had this flag?

In other words, should a variant of this patch be backported if it was a
bug not not use __vlan_hwaccel_put_tag right from the start?

Olaf

RE: [PATCH net] hyperv: Fix vlan_proto setting in netvsc_recv_callback()

[Haiyang Zhang]

> -----Original Message-----
> From: Olaf Hering [mailto:olaf@aepfle.de]
> Sent: Friday, June 14, 2013 11:29 AM
> To: Haiyang Zhang
> Cc: davem@davemloft.net; netdev@vger.kernel.org; KY Srinivasan;
> jasowang@redhat.com; linux-kernel@vger.kernel.org;
> devel@linuxdriverproject.org
> Subject: Re: [PATCH net] hyperv: Fix vlan_proto setting in
> netvsc_recv_callback()
> 
> On Tue, May 28, Haiyang Zhang wrote:
> 
> > Since the recent addition of 8021AD, we need to set the new field
> > vlan_proto in sk_buff. Otherwise, it will trigger BUG() call in
> vlan_proto_idx().
> 
> > @@ -284,7 +285,7 @@ int netvsc_recv_callback(struct hv_device
> > *device_obj,
> >
> >  	skb->protocol = eth_type_trans(skb, net);
> >  	skb->ip_summed = CHECKSUM_NONE;
> > -	skb->vlan_tci = packet->vlan_tci;
> > +	__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), packet-
> >vlan_tci);
> 
> 
> Just curious:
> 
> Doesnt that change behaviour in the sense that __vlan_hwaccel_put_tag()
> now always adds VLAN_TAG_PRESENT to skb->vlan_tci, while before that
> change packet->vlan_tci may or may not had this flag?
> 
> In other words, should a variant of this patch be backported if it was a bug
> not not use __vlan_hwaccel_put_tag right from the start?
> 

Thanks for looking at this. Actually, the previous code was correct, because I 
add the VLAN_TAG_PRESENT if the packet comes from vlan in function
rndis_filter_receive_data():
        if (vlan) {
                pkt->vlan_tci = VLAN_TAG_PRESENT | vlan->vlanid |
                        (vlan->pri << VLAN_PRIO_SHIFT);
        } else {
                pkt->vlan_tci = 0;
        }

But, the new code should be updated below, so the VLAN_TAG_PRESENT won't be set
when it's not from a vlan:
If (VLAN_TAG_PRESENT & packet->vlan_tci)
	__vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), packet- vlan_tci);

I will submit a patch soon.

Thanks,
- Haiyang