bridge: switchdev: Add forward mark support for stacked devices

[karo-tx-linux.git] / Documentation / networking / switchdev.txt

diff --git a/Documentation/networking/switchdev.txt b/Documentation/networking/switchdev.txt
index 2f659129694bd59e685792abb568e80ad477e7da..44235e83799b300df063699454b5732952755ab9 100644 (file)
--- a/Documentation/networking/switchdev.txt
+++ b/Documentation/networking/switchdev.txt
@@ -89,6 +89,18 @@ Typically, the management port is not participating in offloaded data plane and
 is loaded with a different driver, such as a NIC driver, on the management port
 device.
 
+Switch ID
+^^^^^^^^^
+
+The switchdev driver must implement the switchdev op switchdev_port_attr_get
+for SWITCHDEV_ATTR_ID_PORT_PARENT_ID for each port netdev, returning the same
+physical ID for each port of a switch.  The ID must be unique between switches
+on the same system.  The ID does not need to be unique between switches on
+different systems.
+
+The switch ID is used to locate ports on a switch and to know if aggregated
+ports belong to the same switch.
+
 Port Netdev Naming
 ^^^^^^^^^^^^^^^^^^
 
@@ -104,25 +116,13 @@ external configuration.  For example, if a physical 40G port is split logically
 into 4 10G ports, resulting in 4 port netdevs, the device can give a unique
 name for each port using port PHYS name.  The udev rule would be:
 
-SUBSYSTEM=="net", ACTION=="add", DRIVER="<driver>", ATTR{phys_port_name}!="", \
-       NAME="$attr{phys_port_name}"
+SUBSYSTEM=="net", ACTION=="add", ATTR{phys_switch_id}=="<phys_switch_id>", \
+       ATTR{phys_port_name}!="", NAME="swX$attr{phys_port_name}"
 
 Suggested naming convention is "swXpYsZ", where X is the switch name or ID, Y
 is the port name or ID, and Z is the sub-port name or ID.  For example, sw1p1s0
 would be sub-port 0 on port 1 on switch 1.
 
-Switch ID
-^^^^^^^^^
-
-The switchdev driver must implement the switchdev op switchdev_port_attr_get
-for SWITCHDEV_ATTR_ID_PORT_PARENT_ID for each port netdev, returning the same
-physical ID for each port of a switch.  The ID must be unique between switches
-on the same system.  The ID does not need to be unique between switches on
-different systems.
-
-The switch ID is used to locate ports on a switch and to know if aggregated
-ports belong to the same switch.
-
 Port Features
 ^^^^^^^^^^^^^
 
@@ -283,15 +283,10 @@ be sent to the port netdev for processing by the bridge driver.  The
 bridge should not reflood the packet to the same ports the device flooded,
 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
-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
-a group ifindex.
+To avoid duplicate packets, the switch driver should mark a packet as already
+forwarded by setting the skb->offload_fwd_mark bit. The bridge driver will mark
+the skb using the ingress bridge port's mark and prevent it from being forwarded
+through any bridge port with the same mark.
 
 It is possible for the switch device to not handle flooding and push the
 packets up to the bridge driver for flooding.  This is not ideal as the number