Re: [PATCH] doc: fix wrongly referencing dev->skb_mark

On Mon, Oct 10, 2016 at 10:49 PM, Ido Schimmel [off-list ref] wrote:

Hi,

On Mon, Oct 10, 2016 at 08:15:39PM +0900, Ryota Ozaki wrote:

quoted

Section "Flooding L2 domain" says, to avoid duplicated flooding, if
skb->offload_fwd_mark is matched with dev->skb_mark, the kernel will
drop the packet. However, the relevant code in __dev_queue_xmit
compares skb->offload_fwd_mark with dev->offload_fwd_mark, not
dev->skb_mark. I guess the text is wrong.

Signed-off-by: Ryota Ozaki <redacted>
---
 Documentation/networking/switchdev.txt | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/networking/switchdev.txt b/Documentation/networking/switchdev.txt
index 31c3911..d4124a0 100644
--- a/Documentation/networking/switchdev.txt
+++ b/Documentation/networking/switchdev.txt

@@ -286,8 +286,8 @@ otherwise there will be duplicate packets on the wire.
 To avoid duplicate packets, the device/driver should mark a packet as already
 forwarded using skb->offload_fwd_mark.  The same mark is set on the device
 ports in the domain using dev->offload_fwd_mark.  If the skb->offload_fwd_mark
-is non-zero and matches the forwarding egress port's dev->skb_mark, the kernel
-will drop the skb right before transmit on the egress port, with the
+is non-zero and matches the forwarding egress port's dev->offload_fwd_mark,
+the kernel will drop the skb right before transmit on the egress port, with the

I think your tree isn't up to date. The flooding mechanism (and this
document) were modified in commit 6bc506b4fb06 ("bridge: switchdev: Add
forward mark support for stacked devices")
https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=6bc506b4fb065eac3d89ca1ce37082e174493d9e

Oh, right. I forgot to rebase my branch after the 4.9 merge period
and saw the file as of 4.8.

Also, in the future, please specify to which tree (net, net-next) your
patch should go. See:
https://www.kernel.org/doc/Documentation/networking/netdev-FAQ.txt
(under "How do I indicate which tree (net vs. net-next) my patch
should be in?").

Thanks for the pointer. I'll follow the rule next time.

Thanks,
  ozaki-r

Thanks!

quoted

 understanding that the device already forwarded the packet on same egress port.
 The driver can use switchdev_port_fwd_mark_set() to set a globally unique mark
 for port's dev->offload_fwd_mark, based on the port's parent ID (switch ID) and
--
2.7.4