On 01/09/17 15:01, Jiri Pirko wrote:
> Fri, Sep 01, 2017 at 01:45:15PM CEST, niko...@cumulusnetworks.com wrote:
>> On 01/09/17 12:22, Ido Schimmel wrote:
>>> Commit 6bc506b4fb06 ("bridge: switchdev: Add forward mark support for
>>> stacked devices") added the 'offload_fwd_mark' bit to the skb in order
>>> to allow drivers to indicate to the bridge driver that they already
>>> forwarded the packet in L2.
>>>
>>> In case the bit is set, before transmitting the packet from each port,
>>> the port's mark is compared with the mark stored in the skb's control
>>> block. If both marks are equal, we know the packet arrived from a switch
>>> device that already forwarded the packet and it's not re-transmitted.
>>>
>>> However, if the packet is transmitted from the bridge device itself
>>> (e.g., br0), we should clear the 'offload_fwd_mark' bit as the mark
>>> stored in the skb's control block isn't valid.
>>>
>>> This scenario can happen in rare cases where a packet was trapped during
>>> L3 forwarding and forwarded by the kernel to a bridge device.
>>>
>>> Fixes: 6bc506b4fb06 ("bridge: switchdev: Add forward mark support for
>>> stacked devices")
>>> Signed-off-by: Ido Schimmel <ido...@mellanox.com>
>>> Reported-by: Yotam Gigi <yot...@mellanox.com>
>>> Tested-by: Yotam Gigi <yot...@mellanox.com>
>>> Reviewed-by: Jiri Pirko <j...@mellanox.com>
>>> ---
>>> net/bridge/br_device.c | 3 +++
>>> 1 file changed, 3 insertions(+)
>>>
>>> diff --git a/net/bridge/br_device.c b/net/bridge/br_device.c
>>> index 861ae2a165f4..5a7be3bddfa9 100644
>>> --- a/net/bridge/br_device.c
>>> +++ b/net/bridge/br_device.c
>>> @@ -53,6 +53,9 @@ netdev_tx_t br_dev_xmit(struct sk_buff *skb, struct
>>> net_device *dev)
>>> brstats->tx_bytes += skb->len;
>>> u64_stats_update_end(&brstats->syncp);
>>>
>>> +#ifdef CONFIG_NET_SWITCHDEV
>>> + skb->offload_fwd_mark = 0;
>>> +#endif
>>> BR_INPUT_SKB_CB(skb)->brdev = dev;
>>>
>>> skb_reset_mac_header(skb);
>>>
>>
>> Good catch, just one minor nit since there is already an ifdef
>> switchdev/else in br_private.h, why not make this a helper and avoid the
>> ifdef/endif in here ? Currently there is no ifdef switchdev anywhere else.
>
> I think it would be better to convert this to a helper in -net-next and
> take the patch as it is for -net
>
Either way is fine I guess, it's just more work for something as simple. :-)
Whichever way you choose,
Acked-by: Nikolay Aleksandrov <niko...@cumulusnetworks.com>
