net: dsa: avoid suspicious RCU usage for synced VLAN-aware MAC addresses

When using the felix driver (the only one which supports UC filtering
and MC filtering) as a DSA master for a random other DS

net: dsa: avoid suspicious RCU usage for synced VLAN-aware MAC addresses

When using the felix driver (the only one which supports UC filtering
and MC filtering) as a DSA master for a random other DSA switch, one can
see the following stack trace when the downstream switch ports join a
VLAN-aware bridge:

=============================
WARNING: suspicious RCU usage
-----------------------------
net/8021q/vlan_core.c:238 suspicious rcu_dereference_protected() usage!

stack backtrace:
Workqueue: dsa_ordered dsa_slave_switchdev_event_work
Call trace:
lockdep_rcu_suspicious+0x170/0x210
vlan_for_each+0x8c/0x188
dsa_slave_sync_uc+0x128/0x178
__hw_addr_sync_dev+0x138/0x158
dsa_slave_set_rx_mode+0x58/0x70
__dev_set_rx_mode+0x88/0xa8
dev_uc_add+0x74/0xa0
dsa_port_bridge_host_fdb_add+0xec/0x180
dsa_slave_switchdev_event_work+0x7c/0x1c8
process_one_work+0x290/0x568

What it's saying is that vlan_for_each() expects rtnl_lock() context and
it's not getting it, when it's called from the DSA master's ndo_set_rx_mode().

The caller of that - dsa_slave_set_rx_mode() - is the slave DSA
interface's dsa_port_bridge_host_fdb_add() which comes from the deferred
dsa_slave_switchdev_event_work().

We went to great lengths to avoid the rtnl_lock() context in that call
path in commit 0faf890fc519 ("net: dsa: drop rtnl_lock from
dsa_slave_switchdev_event_work"), and calling rtnl_lock() is simply not
an option due to the possibility of deadlocking when calling
dsa_flush_workqueue() from the call paths that do hold rtnl_lock() -
basically all of them.

So, when the DSA master calls vlan_for_each() from its ndo_set_rx_mode(),
the state of the 8021q driver on this device is really not protected
from concurrent access by anything.

Looking at net/8021q/, I don't think that vlan_info->vid_list was
particularly designed with RCU traversal in mind, so introducing an RCU
read-side form of vlan_for_each() - vlan_for_each_rcu() - won't be so
easy, and it also wouldn't be exactly what we need anyway.

In general I believe that the solution isn't in net/8021q/ anyway;
vlan_for_each() is not cut out for this task. DSA doesn't need rtnl_lock()
to be held per se - since it's not a netdev state change that we're
blocking, but rather, just concurrent additions/removals to a VLAN list.
We don't even need sleepable context - the callback of vlan_for_each()
just schedules deferred work.

The proposed escape is to remove the dependency on vlan_for_each() and
to open-code a non-sleepable, rtnl-free alternative to that, based on
copies of the VLAN list modified from .ndo_vlan_rx_add_vid() and
.ndo_vlan_rx_kill_vid().

Fixes: 64fdc5f341db ("net: dsa: sync unicast and multicast addresses for VLAN filters too")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20230626154402.3154454-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: introduce preferred_default_local_cpu_port and use on MT7530

Since the introduction of the OF bindings, DSA has always had a policy that
in case multiple CPU ports are present in the devic

net: dsa: introduce preferred_default_local_cpu_port and use on MT7530

Since the introduction of the OF bindings, DSA has always had a policy that
in case multiple CPU ports are present in the device tree, the numerically
smallest one is always chosen.

The MT7530 switch family, except the switch on the MT7988 SoC, has 2 CPU
ports, 5 and 6, where port 6 is preferable on the MT7531BE switch because
it has higher bandwidth.

The MT7530 driver developers had 3 options:
- to modify DSA when the MT7531 switch support was introduced, such as to
prefer the better port
- to declare both CPU ports in device trees as CPU ports, and live with the
sub-optimal performance resulting from not preferring the better port
- to declare just port 6 in the device tree as a CPU port

Of course they chose the path of least resistance (3rd option), kicking the
can down the road. The hardware description in the device tree is supposed
to be stable - developers are not supposed to adopt the strategy of
piecemeal hardware description, where the device tree is updated in
lockstep with the features that the kernel currently supports.

Now, as a result of the fact that they did that, any attempts to modify the
device tree and describe both CPU ports as CPU ports would make DSA change
its default selection from port 6 to 5, effectively resulting in a
performance degradation visible to users with the MT7531BE switch as can be
seen below.

Without preferring port 6:

[ ID][Role] Interval Transfer Bitrate Retr
[ 5][TX-C] 0.00-20.00 sec 374 MBytes 157 Mbits/sec 734 sender
[ 5][TX-C] 0.00-20.00 sec 373 MBytes 156 Mbits/sec receiver
[ 7][RX-C] 0.00-20.00 sec 1.81 GBytes 778 Mbits/sec 0 sender
[ 7][RX-C] 0.00-20.00 sec 1.81 GBytes 777 Mbits/sec receiver

With preferring port 6:

[ ID][Role] Interval Transfer Bitrate Retr
[ 5][TX-C] 0.00-20.00 sec 1.99 GBytes 856 Mbits/sec 273 sender
[ 5][TX-C] 0.00-20.00 sec 1.99 GBytes 855 Mbits/sec receiver
[ 7][RX-C] 0.00-20.00 sec 1.72 GBytes 737 Mbits/sec 15 sender
[ 7][RX-C] 0.00-20.00 sec 1.71 GBytes 736 Mbits/sec receiver

Using one port for WAN and the other ports for LAN is a very popular use
case which is what this test emulates.

As such, this change proposes that we retroactively modify stable kernels
(which don't support the modification of the CPU port assignments, so as to
let user space fix the problem and restore the throughput) to keep the
mt7530 driver preferring port 6 even with device trees where the hardware
is more fully described.

Fixes: c288575f7810 ("net: dsa: mt7530: Add the support of MT7531 switch")
Signed-off-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net: dsa: replace NETDEV_PRE_CHANGE_HWTSTAMP notifier with a stub

There was a sort of rush surrounding commit 88c0a6b503b7 ("net: create a
netdev notifier for DSA to reject PTP on DSA master"), due

net: dsa: replace NETDEV_PRE_CHANGE_HWTSTAMP notifier with a stub

There was a sort of rush surrounding commit 88c0a6b503b7 ("net: create a
netdev notifier for DSA to reject PTP on DSA master"), due to a desire
to convert DSA's attempt to deny TX timestamping on a DSA master to
something that doesn't block the kernel-wide API conversion from
ndo_eth_ioctl() to ndo_hwtstamp_set().

What was required was a mechanism that did not depend on ndo_eth_ioctl(),
and what was provided was a mechanism that did not depend on
ndo_eth_ioctl(), while at the same time introducing something that
wasn't absolutely necessary - a new netdev notifier.

There have been objections from Jakub Kicinski that using notifiers in
general when they are not absolutely necessary creates complications to
the control flow and difficulties to maintainers who look at the code.
So there is a desire to not use notifiers.

In addition to that, the notifier chain gets called even if there is no
DSA in the system and no one is interested in applying any restriction.

Take the model of udp_tunnel_nic_ops and introduce a stub mechanism,
through which net/core/dev_ioctl.c can call into DSA even when
CONFIG_NET_DSA=m.

Compared to the code that existed prior to the notifier conversion, aka
what was added in commits:
- 4cfab3566710 ("net: dsa: Add wrappers for overloaded ndo_ops")
- 3369afba1e46 ("net: Call into DSA netdevice_ops wrappers")

this is different because we are not overloading any struct
net_device_ops of the DSA master anymore, but rather, we are exposing a
rather specific functionality which is orthogonal to which API is used
to enable it - ndo_eth_ioctl() or ndo_hwtstamp_set().

Also, what is similar is that both approaches use function pointers to
get from built-in code to DSA.

There is no point in replicating the function pointers towards
__dsa_master_hwtstamp_validate() once for every CPU port (dev->dsa_ptr).
Instead, it is sufficient to introduce a singleton struct dsa_stubs,
built into the kernel, which contains a single function pointer to
__dsa_master_hwtstamp_validate().

I find this approach preferable to what we had originally, because
dev->dsa_ptr->netdev_ops->ndo_do_ioctl() used to require going through
struct dsa_port (dev->dsa_ptr), and so, this was incompatible with any
attempts to add any data encapsulation and hide DSA data structures from
the outside world.

Link: https://lore.kernel.org/netdev/20230403083019.120b72fd@kernel.org/
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net: dsa: kill off dsa_priv.h

The last remnants in dsa_priv.h are a netlink-related definition for
which we create a new header, and DSA_MAX_NUM_OFFLOADING_BRIDGES which
is only used from dsa.c, so

net: dsa: kill off dsa_priv.h

The last remnants in dsa_priv.h are a netlink-related definition for
which we create a new header, and DSA_MAX_NUM_OFFLOADING_BRIDGES which
is only used from dsa.c, so move it there.

Some inclusions need to be adjusted now that we no longer have headers
included transitively from dsa_priv.h.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: rename dsa2.c back into dsa.c and create its header

The previous change moved the code into the larger file (dsa2.c) to
minimize the delta. Rename that now to dsa.c, and create dsa.h, wher

net: dsa: rename dsa2.c back into dsa.c and create its header

The previous change moved the code into the larger file (dsa2.c) to
minimize the delta. Rename that now to dsa.c, and create dsa.h, where
all related definitions from dsa_priv.h go.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: move tagging protocol code to tag.{c,h}

It would be nice if tagging protocol drivers could include just the
header they need, since they are (mostly) data path and isolated from
most of th

net: dsa: move tagging protocol code to tag.{c,h}

It would be nice if tagging protocol drivers could include just the
header they need, since they are (mostly) data path and isolated from
most of the other DSA core code does.

Create a tag.c and a tag.h file which are meant to support tagging
protocol drivers.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: move headers exported by slave.c to slave.h

Minimize the use of the bloated dsa_priv.h by moving the prototypes
exported by slave.c to their own header file.

This is just approximate to g

net: dsa: move headers exported by slave.c to slave.h

Minimize the use of the bloated dsa_priv.h by moving the prototypes
exported by slave.c to their own header file.

This is just approximate to get the code structure right. There are some
interdependencies with static inline code left in dsa_priv.h, so leave
slave.h included from there for now.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: move bulk of devlink code to devlink.{c,h}

dsa.c and dsa2.c are bloated with too much off-topic code. Identify all
code related to devlink and move it to a new devlink.c file.

Steer clear

net: dsa: move bulk of devlink code to devlink.{c,h}

dsa.c and dsa2.c are bloated with too much off-topic code. Identify all
code related to devlink and move it to a new devlink.c file.

Steer clear of the dsa_priv.h dumping ground antipattern and create a
dedicated devlink.h for it, which will be included only by the C files
which need it. Usage of dsa_priv.h will be minimized in later patches.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: modularize DSA_TAG_PROTO_NONE

There is no reason that I can see why the no-op tagging protocol should
be registered manually, so make it a module and make all drivers which
have any sort o

net: dsa: modularize DSA_TAG_PROTO_NONE

There is no reason that I can see why the no-op tagging protocol should
be registered manually, so make it a module and make all drivers which
have any sort of reference to DSA_TAG_PROTO_NONE select it.

Note that I don't know if ksz_get_tag_protocol() really needs this,
or if it's just the logic which is poorly written. All switches seem to
have their own tagging protocol, and DSA_TAG_PROTO_NONE is just a
fallback that never gets used.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: unexport dsa_dev_to_net_device()

dsa.o and dsa2.o are linked into the same dsa_core.o, there is no reason
to export this symbol when its only caller is local.

Signed-off-by: Vladimir Olte

net: dsa: unexport dsa_dev_to_net_device()

dsa.o and dsa2.o are linked into the same dsa_core.o, there is no reason
to export this symbol when its only caller is local.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: autoload tag driver module on tagging protocol change

Issue a request_module() call when an attempt to change the tagging
protocol is made, either by sysfs or by device tree. In the case o

net: dsa: autoload tag driver module on tagging protocol change

Issue a request_module() call when an attempt to change the tagging
protocol is made, either by sysfs or by device tree. In the case of
ocelot (the only driver for which the default and the alternative
tagging protocol are compiled as different modules), the user is now no
longer required to insert tag_ocelot_8021q.ko manually.

In the particular case of ocelot, this solves a problem where
tag_ocelot_8021q.ko is built as module, and this is present in the
device tree:

&mscc_felix_port4 {
dsa-tag-protocol = "ocelot-8021q";
};

&mscc_felix_port5 {
dsa-tag-protocol = "ocelot-8021q";
};

Because no one attempts to load the module into the kernel at boot time,
the switch driver will fail to probe (actually forever defer) until
someone manually inserts tag_ocelot_8021q.ko. This is now no longer
necessary and happens automatically.

Rename dsa_find_tagger_by_name() to denote the change in functionality:
there is now feature parity with dsa_tag_driver_get_by_id(), i.o.w. we
also load the module if it's missing.

Link: https://lore.kernel.org/lkml/20221027113248.420216-1-michael@walle.cc/
Suggested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc> # on kontron-sl28 w/ ocelot_8021q
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: rename dsa_tag_driver_get() to dsa_tag_driver_get_by_id()

A future patch will introduce one more way of getting a reference on a
tagging protocl driver (by name). Rename the current method

net: dsa: rename dsa_tag_driver_get() to dsa_tag_driver_get_by_id()

A future patch will introduce one more way of getting a reference on a
tagging protocl driver (by name). Rename the current method to "by_id".

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: strip sysfs "tagging" string of trailing newline

Currently, dsa_find_tagger_by_name() uses sysfs_streq() which works both
with strings that contain \n at the end (echo ocelot > .../dsa/tag

net: dsa: strip sysfs "tagging" string of trailing newline

Currently, dsa_find_tagger_by_name() uses sysfs_streq() which works both
with strings that contain \n at the end (echo ocelot > .../dsa/tagging)
and with strings that don't (printf ocelot > .../dsa/tagging).

There will be a problem once we'll want to construct the modalias string
based on which we auto-load the protocol kernel module. If the sysfs
buffer ends in a newline, we need to strip it first. This is a
preparatory patch specifically for that.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: rename tagging protocol driver modalias

It's autumn cleanup time, and today's target are modaliases.

Michael says that for users of modinfo, "dsa_tag-20" is not the most
suggestive name,

net: dsa: rename tagging protocol driver modalias

It's autumn cleanup time, and today's target are modaliases.

Michael says that for users of modinfo, "dsa_tag-20" is not the most
suggestive name, and recommends a change to "dsa_tag-id-20".

Andrew points out that other modaliases have a prefix delimited by
colons, so he recommends "dsa_tag:20" instead of "dsa_tag-20".

To satisfy both proposals, Florian recommends "dsa_tag:id-20".

The modaliases are not stable ABI, and the essential information
(protocol ID) is still conveyed in the new string, which
request_module() must be adapted to form.

Link: 20221027210830.3577793-1-vladimir.oltean@nxp.com
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Suggested-by: Michael Walle <michael@walle.cc>
Suggested-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: add support for DSA rx offloading via metadata dst

If a metadata dst is present with the type METADATA_HW_PORT_MUX on a dsa cpu
port netdev, assume that it carries the port number and that

net: dsa: add support for DSA rx offloading via metadata dst

If a metadata dst is present with the type METADATA_HW_PORT_MUX on a dsa cpu
port netdev, assume that it carries the port number and that there is no DSA
tag present in the skb data.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

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net: dsa: allow the DSA master to be seen and changed through rtnetlink

Some DSA switches have multiple CPU ports, which can be used to improve
CPU termination throughput, but DSA, through dsa_tree_

net: dsa: allow the DSA master to be seen and changed through rtnetlink

Some DSA switches have multiple CPU ports, which can be used to improve
CPU termination throughput, but DSA, through dsa_tree_setup_cpu_ports(),
sets up only the first one, leading to suboptimal use of hardware.

The desire is to not change the default configuration but to permit the
user to create a dynamic mapping between individual user ports and the
CPU port that they are served by, configurable through rtnetlink. It is
also intended to permit load balancing between CPU ports, and in that
case, the foreseen model is for the DSA master to be a bonding interface
whose lowers are the physical DSA masters.

To that end, we create a struct rtnl_link_ops for DSA user ports with
the "dsa" kind. We expose the IFLA_DSA_MASTER link attribute that
contains the ifindex of the newly desired DSA master.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>

show more ...

net: dsa: delete dsa_port_walk_{fdbs,mdbs}

All the users of these functions are gone, delete them before they gain
new ones.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by:

net: dsa: delete dsa_port_walk_{fdbs,mdbs}

All the users of these functions are gone, delete them before they gain
new ones.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

show more ...

net: dsa: remove unused headers

Reduce a number of included headers to a necessary minimum.

Signed-off-by: Marcin Wojtas <mw@semihalf.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: dsa: felix: avoid early deletion of host FDB entries

The Felix driver declares FDB isolation but puts all standalone ports in
VID 0. This is mostly problem-free as discussed with Alvin here:
ht

net: dsa: felix: avoid early deletion of host FDB entries

The Felix driver declares FDB isolation but puts all standalone ports in
VID 0. This is mostly problem-free as discussed with Alvin here:
https://patchwork.kernel.org/project/netdevbpf/cover/20220302191417.1288145-1-vladimir.oltean@nxp.com/#24763870

however there is one catch. DSA still thinks that FDB entries are
installed on the CPU port as many times as there are user ports, and
this is problematic when multiple user ports share the same MAC address.

Consider the default case where all user ports inherit their MAC address
from the DSA master, and then the user runs:

ip link set swp0 address 00:01:02:03:04:05

The above will make dsa_slave_set_mac_address() call
dsa_port_standalone_host_fdb_add() for 00:01:02:03:04:05 in port 0's
standalone database, and dsa_port_standalone_host_fdb_del() for the old
address of swp0, again in swp0's standalone database.

Both the ->port_fdb_add() and ->port_fdb_del() will be propagated down
to the felix driver, which will end up deleting the old MAC address from
the CPU port. But this is still in use by other user ports, so we end up
breaking unicast termination for them.

There isn't a problem in the fact that DSA keeps track of host
standalone addresses in the individual database of each user port: some
drivers like sja1105 need this. There also isn't a problem in the fact
that some drivers choose the same VID/FID for all standalone ports.
It is just that the deletion of these host addresses must be delayed
until they are known to not be in use any longer, and only the driver
has this knowledge. Since DSA keeps these addresses in &cpu_dp->fdbs and
&cpu_db->mdbs, it is just a matter of walking over those lists and see
whether the same MAC address is present on the CPU port in the port db
of another user port.

I have considered reusing the generic dsa_port_walk_fdbs() and
dsa_port_walk_mdbs() schemes for this, but locking makes it difficult.
In the ->port_fdb_add() method and co, &dp->addr_lists_lock is held, but
dsa_port_walk_fdbs() also acquires that lock. Also, even assuming that
we introduce an unlocked variant of the address iterator, we'd still
need some relatively complex data structures, and a void *ctx in the
dsa_fdb_walk_cb_t which we don't currently pass, such that drivers are
able to figure out, after iterating, whether the same MAC address is or
isn't present in the port db of another port.

All the above, plus the fact that I expect other drivers to follow the
same model as felix where all standalone ports use the same FID, made me
conclude that a generic method provided by DSA is necessary:
dsa_fdb_present_in_other_db() and the mdb equivalent. Felix calls this
from the ->port_fdb_del() handler for the CPU port, when the database
was classified to either a port db, or a LAG db.

For symmetry, we also call this from ->port_fdb_add(), because if the
address was installed once, then installing it a second time serves no
purpose: it's already in hardware in VID 0 and it affects all standalone
ports.

This change moves dsa_db_equal() from switch.c to dsa.c, since it now
has one more caller.

Fixes: 54c319846086 ("net: mscc: ocelot: enforce FDB isolation when VLAN-unaware")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

show more ...

net: dsa: return success if there was nothing to do

Clang static analysis reports this representative issue
dsa.c:486:2: warning: Undefined or garbage value
returned to caller
return err;
^~~~

net: dsa: return success if there was nothing to do

Clang static analysis reports this representative issue
dsa.c:486:2: warning: Undefined or garbage value
returned to caller
return err;
^~~~~~~~~~

err is only set in the loop. If the loop is empty,
garbage will be returned. So initialize err to 0
to handle this noop case.

Signed-off-by: Tom Rix <trix@redhat.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: dsa: felix: migrate host FDB and MDB entries when changing tag proto

The "ocelot" and "ocelot-8021q" tagging protocols make use of different
hardware resources, and host FDB entries have differ

net: dsa: felix: migrate host FDB and MDB entries when changing tag proto

The "ocelot" and "ocelot-8021q" tagging protocols make use of different
hardware resources, and host FDB entries have different destination
ports in the switch analyzer module, practically speaking.

So when the user requests a tagging protocol change, the driver must
migrate all host FDB and MDB entries from the NPI port (in fact CPU port
module) towards the same physical port, but this time used as a regular
port.

It is pointless for the felix driver to keep a copy of the host
addresses, when we can create and export DSA helpers for walking through
the addresses that it already needs to keep on the CPU port, for
refcounting purposes.

felix_classify_db() is moved up to avoid a forward declaration.

We pass "bool change" because dp->fdbs and dp->mdbs are uninitialized
lists when felix_setup() first calls felix_set_tag_protocol(), so we
need to avoid calling dsa_port_walk_fdbs() during probe time.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: dsa: mv88e6xxx: flush switchdev FDB workqueue before removing VLAN

mv88e6xxx is special among DSA drivers in that it requires the VTU to
contain the VID of the FDB entry it modifies in
mv88e6xx

net: dsa: mv88e6xxx: flush switchdev FDB workqueue before removing VLAN

mv88e6xxx is special among DSA drivers in that it requires the VTU to
contain the VID of the FDB entry it modifies in
mv88e6xxx_port_db_load_purge(), otherwise it will return -EOPNOTSUPP.

Sometimes due to races this is not always satisfied even if external
code does everything right (first deletes the FDB entries, then the
VLAN), because DSA commits to hardware FDB entries asynchronously since
commit c9eb3e0f8701 ("net: dsa: Add support for learning FDB through
notification").

Therefore, the mv88e6xxx driver must close this race condition by
itself, by asking DSA to flush the switchdev workqueue of any FDB
deletions in progress, prior to exiting a VLAN.

Fixes: c9eb3e0f8701 ("net: dsa: Add support for learning FDB through notification")
Reported-by: Rafael Richter <rafael.richter@gin.de>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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devlink: Simplify devlink resources unregister call

The devlink_resources_unregister() used second parameter as an
entry point for the recursive removal of devlink resources. None
of the callers out

devlink: Simplify devlink resources unregister call

The devlink_resources_unregister() used second parameter as an
entry point for the recursive removal of devlink resources. None
of the callers outside of devlink core needed to use this field,
so let's remove it.

As part of this removal, the "struct devlink_resource" was moved
from .h to .c file as it is not possible to use in any place in
the code except devlink.c.

Signed-off-by: Leon Romanovsky <leonro@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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net: dsa: remove the "dsa_to_port in a loop" antipattern from the core

Ever since Vivien's conversion of the ds->ports array into a dst->ports
list, and the introduction of dsa_to_port, iterations t

net: dsa: remove the "dsa_to_port in a loop" antipattern from the core

Ever since Vivien's conversion of the ds->ports array into a dst->ports
list, and the introduction of dsa_to_port, iterations through the ports
of a switch became quadratic whenever dsa_to_port was needed.

dsa_to_port can either be called directly, or indirectly through the
dsa_is_{user,cpu,dsa,unused}_port helpers.

Use the newly introduced dsa_switch_for_each_port() iteration macro
that works with the iterator variable being a struct dsa_port *dp
directly, and not an int i. It is an expensive variable to go from i to
dp, but cheap to go from dp to i.

This macro iterates through the entire ds->dst->ports list and filters
by the ports belonging just to the switch provided as argument.

Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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Revert "net: dsa: mv88e6xxx: flush switchdev FDB workqueue before removing VLAN"

This reverts commit 2566a89b9e163b2fcd104d6005e0149f197b8a48 which is
commit a2614140dc0f467a83aa3bb4b6ee2d6480a76202

Revert "net: dsa: mv88e6xxx: flush switchdev FDB workqueue before removing VLAN"

This reverts commit 2566a89b9e163b2fcd104d6005e0149f197b8a48 which is
commit a2614140dc0f467a83aa3bb4b6ee2d6480a76202 upstream.

The above change depends on upstream commit 0faf890fc519 ("net: dsa:
drop rtnl_lock from dsa_slave_switchdev_event_work"), which is not
present in linux-5.15.y. Without that change, waiting for the switchdev
workqueue causes deadlocks on the rtnl_mutex.

Backporting the dependency commit isn't trivial/desirable, since it
requires that the following dependencies of the dependency are also
backported:

df405910ab9f net: dsa: sja1105: wait for dynamic config command completion on writes too
eb016afd83a9 net: dsa: sja1105: serialize access to the dynamic config interface
2468346c5677 net: mscc: ocelot: serialize access to the MAC table
f7eb4a1c0864 net: dsa: b53: serialize access to the ARL table
cf231b436f7c net: dsa: lantiq_gswip: serialize access to the PCE registers
338a3a4745aa net: dsa: introduce locking for the address lists on CPU and DSA ports

and then this bugfix on top:

8940e6b669ca ("net: dsa: avoid call to __dev_set_promiscuity() while rtnl_mutex isn't held")

Reported-by: Daniel Suchy <danny@danysek.cz>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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