net: bridge: switchdev: let drivers inform which bridge ports are offloaded

On reception of an skb, the bridge checks if it was marked as 'already
forwarded in hardware' (checks if skb->offload_fwd_mark == 1), and if it
is, it assigns the source hardware domain of that skb based on the
hardware domain of the ingress port. Then during forwarding, it enforces
that the egress port must have a different hardware domain than the
ingress one (this is done in nbp_switchdev_allowed_egress).

Non-switchdev drivers don't report any physical switch id (neither
through devlink nor .ndo_get_port_parent_id), therefore the bridge
assigns them a hardware domain of 0, and packets coming from them will
always have skb->offload_fwd_mark = 0. So there aren't any restrictions.

Problems appear due to the fact that DSA would like to perform software
fallback for bonding and team interfaces that the physical switch cannot
offload.

+-- br0 ---+
/ / | \
/ / | \
/ | | bond0
/ | | / \
swp0 swp1 swp2 swp3 swp4

There, it is desirable that the presence of swp3 and swp4 under a
non-offloaded LAG does not preclude us from doing hardware bridging
beteen swp0, swp1 and swp2. The bandwidth of the CPU is often times high
enough that software bridging between {swp0,swp1,swp2} and bond0 is not
impractical.

But this creates an impossible paradox given the current way in which
port hardware domains are assigned. When the driver receives a packet
from swp0 (say, due to flooding), it must set skb->offload_fwd_mark to
something.

- If we set it to 0, then the bridge will forward it towards swp1, swp2
and bond0. But the switch has already forwarded it towards swp1 and
swp2 (not to bond0, remember, that isn't offloaded, so as far as the
switch is concerned, ports swp3 and swp4 are not looking up the FDB,
and the entire bond0 is a destination that is strictly behind the
CPU). But we don't want duplicated traffic towards swp1 and swp2, so
it's not ok to set skb->offload_fwd_mark = 0.

- If we set it to 1, then the bridge will not forward the skb towards
the ports with the same switchdev mark, i.e. not to swp1, swp2 and
bond0. Towards swp1 and swp2 that's ok, but towards bond0? It should
have forwarded the skb there.

So the real issue is that bond0 will be assigned the same hardware
domain as {swp0,swp1,swp2}, because the function that assigns hardware
domains to bridge ports, nbp_switchdev_add(), recurses through bond0's
lower interfaces until it finds something that implements devlink (calls
dev_get_port_parent_id with bool recurse = true). This is a problem
because the fact that bond0 can be offloaded by swp3 and swp4 in our
example is merely an assumption.

A solution is to give the bridge explicit hints as to what hardware
domain it should use for each port.

Currently, the bridging offload is very 'silent': a driver registers a
netdevice notifier, which is put on the netns's notifier chain, and
which sniffs around for NETDEV_CHANGEUPPER events where the upper is a
bridge, and the lower is an interface it knows about (one registered by
this driver, normally). Then, from within that notifier, it does a bunch
of stuff behind the bridge's back, without the bridge necessarily
knowing that there's somebody offloading that port. It looks like this:

ip link set swp0 master br0
|
v
br_add_if() calls netdev_master_upper_dev_link()
|
v
call_netdevice_notifiers
|
v
dsa_slave_netdevice_event
|
v
oh, hey! it's for me!
|
v
.port_bridge_join

What we do to solve the conundrum is to be less silent, and change the
switchdev drivers to present themselves to the bridge. Something like this:

ip link set swp0 master br0
|
v
br_add_if() calls netdev_master_upper_dev_link()
|
v bridge: Aye! I'll use this
call_netdevice_notifiers ^ ppid as the
| | hardware domain for
v | this port, and zero
dsa_slave_netdevice_event | if I got nothing.
| |
v |
oh, hey! it's for me! |
| |
v |
.port_bridge_join |
| |
+------------------------+
switchdev_bridge_port_offload(swp0, swp0)

Then stacked interfaces (like bond0 on top of swp3/swp4) would be
treated differently in DSA, depending on whether we can or cannot
offload them.

The offload case:

ip link set bond0 master br0
|
v
br_add_if() calls netdev_master_upper_dev_link()
|
v bridge: Aye! I'll use this
call_netdevice_notifiers ^ ppid as the
| | switchdev mark for
v | bond0.
dsa_slave_netdevice_event | Coincidentally (or not),
| | bond0 and swp0, swp1, swp2
v | all have the same switchdev
hmm, it's not quite for me, | mark now, since the ASIC
but my driver has already | is able to forward towards
called .port_lag_join | all these ports in hw.
for it, because I have |
a port with dp->lag_dev == bond0. |
| |
v |
.port_bridge_join |
for swp3 and swp4 |
| |
+------------------------+
switchdev_bridge_port_offload(bond0, swp3)
switchdev_bridge_port_offload(bond0, swp4)

And the non-offload case:

ip link set bond0 master br0
|
v
br_add_if() calls netdev_master_upper_dev_link()
|
v bridge waiting:
call_netdevice_notifiers ^ huh, switchdev_bridge_port_offload
| | wasn't called, okay, I'll use a
v | hwdom of zero for this one.
dsa_slave_netdevice_event : Then packets received on swp0 will
| : not be software-forwarded towards
v : swp1, but they will towards bond0.
it's not for me, but
bond0 is an upper of swp3
and swp4, but their dp->lag_dev
is NULL because they couldn't
offload it.

Basically we can draw the conclusion that the lowers of a bridge port
can come and go, so depending on the configuration of lowers for a
bridge port, it can dynamically toggle between offloaded and unoffloaded.
Therefore, we need an equivalent switchdev_bridge_port_unoffload too.

This patch changes the way any switchdev driver interacts with the
bridge. From now on, everybody needs to call switchdev_bridge_port_offload
and switchdev_bridge_port_unoffload, otherwise the bridge will treat the
port as non-offloaded and allow software flooding to other ports from
the same ASIC.

Note that these functions lay the ground for a more complex handshake
between switchdev drivers and the bridge in the future.

For drivers that will request a replay of the switchdev objects when
they offload and unoffload a bridge port (DSA, dpaa2-switch, ocelot), we
place the call to switchdev_bridge_port_unoffload() strategically inside
the NETDEV_PRECHANGEUPPER notifier's code path, and not inside
NETDEV_CHANGEUPPER. This is because the switchdev object replay helpers
need the netdev adjacency lists to be valid, and that is only true in
NETDEV_PRECHANGEUPPER.

Cc: Vadym Kochan <vkochan@marvell.com>
Cc: Taras Chornyi <tchornyi@marvell.com>
Cc: Ioana Ciornei <ioana.ciornei@nxp.com>
Cc: Lars Povlsen <lars.povlsen@microchip.com>
Cc: Steen Hegelund <Steen.Hegelund@microchip.com>
Cc: UNGLinuxDriver@microchip.com
Cc: Claudiu Manoil <claudiu.manoil@nxp.com>
Cc: Alexandre Belloni <alexandre.belloni@bootlin.com>
Cc: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Ioana Ciornei <ioana.ciornei@nxp.com> # dpaa2-switch: regression
Acked-by: Ioana Ciornei <ioana.ciornei@nxp.com> # dpaa2-switch
Tested-by: Horatiu Vultur <horatiu.vultur@microchip.com> # ocelot-switch
Signed-off-by: David S. Miller <davem@davemloft.net>

net: switchdev: remove the transaction structure from port attributes

Since the introduction of the switchdev API, port attributes were
transmitted to drivers for offloading using a two-step transactional
model, with a prepare phase that was supposed to catch all errors, and a
commit phase that was supposed to never fail.

Some classes of failures can never be avoided, like hardware access, or
memory allocation. In the latter case, merely attempting to move the
memory allocation to the preparation phase makes it impossible to avoid
memory leaks, since commit 91cf8eceffc1 ("switchdev: Remove unused
transaction item queue") which has removed the unused mechanism of
passing on the allocated memory between one phase and another.

It is time we admit that separating the preparation from the commit
phase is something that is best left for the driver to decide, and not
something that should be baked into the API, especially since there are
no switchdev callers that depend on this.

This patch removes the struct switchdev_trans member from switchdev port
attribute notifier structures, and converts drivers to not look at this
member.

In part, this patch contains a revert of my previous commit 2e554a7a5d8a
("net: dsa: propagate switchdev vlan_filtering prepare phase to
drivers").

For the most part, the conversion was trivial except for:
- Rocker's world implementation based on Broadcom OF-DPA had an odd
implementation of ofdpa_port_attr_bridge_flags_set. The conversion was
done mechanically, by pasting the implementation twice, then only
keeping the code that would get executed during prepare phase on top,
then only keeping the code that gets executed during the commit phase
on bottom, then simplifying the resulting code until this was obtained.
- DSA's offloading of STP state, bridge flags, VLAN filtering and
multicast router could be converted right away. But the ageing time
could not, so a shim was introduced and this was left for a further
commit.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Jiri Pirko <jiri@nvidia.com>
Reviewed-by: Kurt Kanzenbach <kurt@linutronix.de> # hellcreek
Reviewed-by: Linus Walleij <linus.walleij@linaro.org> # RTL8366RB
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 152

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms of the gnu general public license as published by
the free software foundation either version 2 of the license or at
your option any later version

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 3029 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070032.746973796@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

rocker: Remove getting PORT_BRIDGE_FLAGS

There is no code that attempts to get the
SWITCHDEV_ATTR_ID_PORT_BRIDGE_FLAGS attribute, remove support for that.

Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: Remove support bridge bypass FDB

The FDB add/delete are now done through the notification chain. The FDBs
are synced with the bridge and there is no need for extra dumping.

Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: Remove support for bypass bridge port attributes/vlan set

The bridge port attributes/vlan for mlxsw devices should be set only
from bridge code. The vlans are synced totally with the bridge so
there is no need to special dump support.

Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: Change world_ops API and implementation to be switchdev independant

Currently the switchdev_trans struct is embedded in the world_ops API.
In order to add support for adding FDB via a notfication chain the API should
be switchdev independent.

Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: Add support for querying supported bridge flags

Add support for querying supported bridge flags.

Signed-off-by: Arkadi Sharshevsky <arkadis@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: Create an ordered workqueue for FIB offload

As explained in the previous commits, we need to process FIB entries
addition / deletion events in FIFO order or otherwise we can have a
mismatch between the kernel's FIB table and the device's.

Create an ordered workqueue for rocker to which these work items will be
submitted to.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: use FIB notifications instead of switchdev calls

Until now, in order to offload a FIB entry to HW we use switchdev op.
Use the newly introduced FIB notifier infrasturucture to process
FIB entries to offload the in HW.
Abort mechanism is now handled within the rocker driver.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: move ageing_time from struct rocker to struct ofdpa

This is OF-DPA specific, used only there, similar to
ofdpa_port->ageing_time. So move it to OF-DPA code.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: set FDB cleanup timer according to lowest ageing time

In rocker, ageing time is a per-port attribute, so the next time the FDB
cleanup timer fires should be set according to the lowest ageing time.

This will later allow us to delete the BR_MIN_AGEING_TIME macro, which was
added to guarantee minimum ageing time in the bridge layer, thereby breaking
existing behavior.

Signed-off-by: Ido Schimmel <idosch@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: move OF-DPA stuff into separate file

Carve out OF-DPA would specific code from the common file to the world
file. This change required struct rocker and struct rocker_port split
into world specific struct ofdpa and struct ofdpa_port. Along with this
the world specific functions and defines were renamed from prefix
"rocker_" to "ofdpa_".

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: introduce worlds infrastructure

This is another step on the way to per-world clean cut. Introduce world
ops hooks which each world can implement in world-specific way.
Also introduce world infrastructure along with OF-DPA world stub.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: move rocker and rocker_port structs into header

And take some other related thing along. They are going to be pushed
into of-dpa part anyway.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: push tlv processing into separate files

Carve out TLV processing helpers into separate files.

Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Acked-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: add offload_fwd_mark support

If device flags ingress packet as "fwd offload", mark the
skb->offlaod_fwd_mark using the ingress port's dev->offlaod_fwd_mark. This
will be the hint to the kernel that this packet has already been forwarded
by device to egress ports matching skb->offlaod_fwd_mark.

For rocker, derive port dev->offlaod_fwd_mark based on device switch ID and
port ifindex. If port is bridged, use the bridge ifindex rather than the
port ifindex.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: add change MTU support

Implement ndo_change_mtu: on MTU change, reallocate Rx ring bufs and signal
HW of new port MTU value.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Reviewed-by: Simon Horman <simon.horman@netronome.com>
Tested-by: Simon Horman <simon.horman@netronome.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: make checkpatch -f clean

Well almost clean: ignore the CHECKs for space after cast operator and some
longer-than-80 char cases where for readability it's better to keep as-is.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: add support for phys_port_name

Implement the phys_port_name operation. Port names are pulled from the
rocker hardware model in qemu and default to the qemu name + port id.
e.g.,

sw1p1: flags=4098<BROADCAST,MULTICAST> mtu 1500
ether 52:54:00:12:35:01 txqueuelen 1000 (Ethernet)
RX packets 0 bytes 0 (0.0 B)
RX errors 0 dropped 0 overruns 0 frame 0
TX packets 0 bytes 0 (0.0 B)
TX errors 0 dropped 0 overruns 0 carrier 0 collisions 0

where 'sw1' comes from the qemu command line -device rocker,name=sw1, and
'p1' is port 1.

Patch is adapted from Scott's phys_port_id patch.

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Scott Feldman <sfeldma@gmail.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: sparse: fix dynamic allocation on stack warning

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: rename lport to pport

This is just a rename of physical ports from "lport" to "pport". Not a
functional change. OF-DPA uses logical ports (lport) for tunnels, but the
driver (and device) were using "lport" for physical ports. Renaming physical
ports references to "pport", freeing up "lport" for use later with tunnels.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: fix non-portable err return codes

The rocker device returns error codes if something goes wrong with descriptor
processing. Originally the device used standard errno codes for different
errors, but since those errno codes aren't portable across ARCHs, the device
now returns hard-coded error codes that stay constant across diff ARCHs. Fix
driver to use those same hard-coded values.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Acked-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: rocker: Add support for retrieving port level statistics

Add support for retrieving port level statistics from device.
Hook is added for ethtool's stats functionality. For example,

$ ethtool -S eth3
NIC statistics:
rx_packets: 12
rx_bytes: 2790
rx_dropped: 0
rx_errors: 0
tx_packets: 8
tx_bytes: 728
tx_dropped: 0
tx_errors: 0

Signed-off-by: David Ahern <dsahern@gmail.com>
Acked-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: add ndo_bridge_setlink/getlink support for learning policy

Rocker ports will use new "swdev" hwmode for bridge port offload policy.
Current supported policy settings are BR_LEARNING and BR_LEARNING_SYNC.
User can turn on/off device port FDB learning and syncing to bridge.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>

rocker: introduce rocker switch driver

This patch introduces the first driver to benefit from the switchdev
infrastructure and to implement newly introduced switch ndos. This is a
driver for emulated switch chip implemented in qemu:
https://github.com/sfeldma/qemu-rocker/

This patch is a result of joint work with Scott Feldman.

Signed-off-by: Scott Feldman <sfeldma@gmail.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Reviewed-by: Thomas Graf <tgraf@suug.ch>
Reviewed-by: John Fastabend <john.r.fastabend@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>