Prior to 1d27732f ("net: dsa: setup and teardown ports"), we would
not treat failures to set-up an user port as fatal, but after this
commit we would, which is a regression for some systems where interfaces
may be declared in the Device Tree, but the underlying hardware may not
be present (pluggable daughter cards for instance).

Fixes: 1d27732f ("net: dsa: setup and teardown ports")
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Many switches don't have an explicit knob for configuring the MTU
(maximum transmission unit per interface).  Instead, they do the
length-based packet admission checks on the ingress interface, for
reasons that are easy to understand (why would you accept a packet in
the queuing subsystem if you know you're going to drop it anyway).

So it is actually the MRU that these switches permit configuring.

In Linux there only exists the IFLA_MTU netlink attribute and the
associated dev_set_mtu function. The comments like to play blind and say
that it's changing the "maximum transfer unit", which is to say that
there isn't any directionality in the meaning of the MTU word. So that
is the interpretation that this patch is giving to things: MTU == MRU.

When 2 interfaces having different MTUs are bridged, the bridge driver
MTU auto-adjustment logic kicks in: what br_mtu_auto_adjust() does is it
adjusts the MTU of the bridge net device itself (and not that of the
slave net devices) to the minimum value of all slave interfaces, in
order for forwarded packets to not exceed the MTU regardless of the
interface they are received and send on.

The idea behind this behavior, and why the slave MTUs are not adjusted,
is that normal termination from Linux over the L2 forwarding domain
should happen over the bridge net device, which _is_ properly limited by
the minimum MTU. And termination over individual slave devices is
possible even if those are bridged. But that is not "forwarding", so
there's no reason to do normalization there, since only a single
interface sees that packet.

The problem with those switches that can only control the MRU is with
the offloaded data path, where a packet received on an interface with
MRU 9000 would still be forwarded to an interface with MRU 1500. And the
br_mtu_auto_adjust() function does not really help, since the MTU
configured on the bridge net device is ignored.

In order to enforce the de-facto MTU == MRU rule for these switches, we
need to do MTU normalization, which means: in order for no packet larger
than the MTU configured on this port to be sent, then we need to limit
the MRU on all ports that this packet could possibly come from. AKA
since we are configuring the MRU via MTU, it means that all ports within
a bridge forwarding domain should have the same MTU.

And that is exactly what this patch is trying to do.

>From an implementation perspective, we try to follow the intent of the
user, otherwise there is a risk that we might livelock them (they try to
change the MTU on an already-bridged interface, but we just keep
changing it back in an attempt to keep the MTU normalized). So the MTU
that the bridge is normalized to is either:

 - The most recently changed one:

   ip link set dev swp0 master br0
   ip link set dev swp1 master br0
   ip link set dev swp0 mtu 1400

   This sequence will make swp1 inherit MTU 1400 from swp0.

 - The one of the most recently added interface to the bridge:

   ip link set dev swp0 master br0
   ip link set dev swp1 mtu 1400
   ip link set dev swp1 master br0

   The above sequence will make swp0 inherit MTU 1400 as well.
Suggested-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

DSA sets up a switch tree little by little. Every switch of the N
members of the tree calls dsa_register_switch, and (N - 1) will just
touch the dst->ports list with their ports and quickly exit. Only the
last switch that calls dsa_register_switch will find all DSA links
complete in dsa_tree_setup_routing_table, and not return zero as a
result but instead go ahead and set up the entire DSA switch tree
(practically on behalf of the other switches too).

The trouble is that the (N - 1) switches don't clean up after themselves
after they get an error such as EPROBE_DEFER. Their footprint left in
dst->ports by dsa_switch_touch_ports is still there. And switch N, the
one responsible with actually setting up the tree, is going to work with
those stale dp, dp->ds and dp->ds->dev pointers. In particular ds and
ds->dev might get freed by the device driver.

Be there a 2-switch tree and the following calling order:
- Switch 1 calls dsa_register_switch
  - Calls dsa_switch_touch_ports, populates dst->ports
  - Calls dsa_port_parse_cpu, gets -EPROBE_DEFER, exits.
- Switch 2 calls dsa_register_switch
  - Calls dsa_switch_touch_ports, populates dst->ports
  - Probe doesn't get deferred, so it goes ahead.
  - Calls dsa_tree_setup_routing_table, which returns "complete == true"
    due to Switch 1 having called dsa_switch_touch_ports before.
  - Because the DSA links are complete, it calls dsa_tree_setup_switches
    now.
  - dsa_tree_setup_switches iterates through dst->ports, initializing
    the Switch 1 ds structure (invalid) and the Switch 2 ds structure
    (valid).
  - Undefined behavior (use after free, sometimes NULL pointers, etc).

Real example below (debugging prints added by me, as well as guards
against NULL pointers):

[    5.477947] dsa_tree_setup_switches: Setting up port 0 of switch ffffff803df0b980 (dev ffffff803f775c00)
[    6.313002] dsa_tree_setup_switches: Setting up port 1 of switch ffffff803df0b980 (dev ffffff803f775c00)
[    6.319932] dsa_tree_setup_switches: Setting up port 2 of switch ffffff803df0b980 (dev ffffff803f775c00)
[    6.329693] dsa_tree_setup_switches: Setting up port 3 of switch ffffff803df0b980 (dev ffffff803f775c00)
[    6.339458] dsa_tree_setup_switches: Setting up port 4 of switch ffffff803df0b980 (dev ffffff803f775c00)
[    6.349226] dsa_tree_setup_switches: Setting up port 5 of switch ffffff803df0b980 (dev ffffff803f775c00)
[    6.358991] dsa_tree_setup_switches: Setting up port 6 of switch ffffff803df0b980 (dev ffffff803f775c00)
[    6.368758] dsa_tree_setup_switches: Setting up port 7 of switch ffffff803df0b980 (dev ffffff803f775c00)
[    6.378524] dsa_tree_setup_switches: Setting up port 8 of switch ffffff803df0b980 (dev ffffff803f775c00)
[    6.388291] dsa_tree_setup_switches: Setting up port 9 of switch ffffff803df0b980 (dev ffffff803f775c00)
[    6.398057] dsa_tree_setup_switches: Setting up port 10 of switch ffffff803df0b980 (dev ffffff803f775c00)
[    6.407912] dsa_tree_setup_switches: Setting up port 0 of switch ffffff803da02f80 (dev 0000000000000000)
[    6.417682] dsa_tree_setup_switches: Setting up port 1 of switch ffffff803da02f80 (dev 0000000000000000)
[    6.427446] dsa_tree_setup_switches: Setting up port 2 of switch ffffff803da02f80 (dev 0000000000000000)
[    6.437212] dsa_tree_setup_switches: Setting up port 3 of switch ffffff803da02f80 (dev 0000000000000000)
[    6.446979] dsa_tree_setup_switches: Setting up port 4 of switch ffffff803da02f80 (dev 0000000000000000)
[    6.456744] dsa_tree_setup_switches: Setting up port 5 of switch ffffff803da02f80 (dev 0000000000000000)
[    6.466512] dsa_tree_setup_switches: Setting up port 6 of switch ffffff803da02f80 (dev 0000000000000000)
[    6.476277] dsa_tree_setup_switches: Setting up port 7 of switch ffffff803da02f80 (dev 0000000000000000)
[    6.486043] dsa_tree_setup_switches: Setting up port 8 of switch ffffff803da02f80 (dev 0000000000000000)
[    6.495810] dsa_tree_setup_switches: Setting up port 9 of switch ffffff803da02f80 (dev 0000000000000000)
[    6.505577] dsa_tree_setup_switches: Setting up port 10 of switch ffffff803da02f80 (dev 0000000000000000)
[    6.515433] dsa_tree_setup_switches: Setting up port 0 of switch ffffff803db15b80 (dev ffffff803d8e4800)
[    7.354120] dsa_tree_setup_switches: Setting up port 1 of switch ffffff803db15b80 (dev ffffff803d8e4800)
[    7.361045] dsa_tree_setup_switches: Setting up port 2 of switch ffffff803db15b80 (dev ffffff803d8e4800)
[    7.370805] dsa_tree_setup_switches: Setting up port 3 of switch ffffff803db15b80 (dev ffffff803d8e4800)
[    7.380571] dsa_tree_setup_switches: Setting up port 4 of switch ffffff803db15b80 (dev ffffff803d8e4800)
[    7.390337] dsa_tree_setup_switches: Setting up port 5 of switch ffffff803db15b80 (dev ffffff803d8e4800)
[    7.400104] dsa_tree_setup_switches: Setting up port 6 of switch ffffff803db15b80 (dev ffffff803d8e4800)
[    7.409872] dsa_tree_setup_switches: Setting up port 7 of switch ffffff803db15b80 (dev ffffff803d8e4800)
[    7.419637] dsa_tree_setup_switches: Setting up port 8 of switch ffffff803db15b80 (dev ffffff803d8e4800)
[    7.429403] dsa_tree_setup_switches: Setting up port 9 of switch ffffff803db15b80 (dev ffffff803d8e4800)
[    7.439169] dsa_tree_setup_switches: Setting up port 10 of switch ffffff803db15b80 (dev ffffff803d8e4800)

The solution is to recognize that the functions that call
dsa_switch_touch_ports (dsa_switch_parse_of, dsa_switch_parse) have side
effects, and therefore one should clean up their side effects on error
path. The cleanup of dst->ports was taken from dsa_switch_remove and
moved into a dedicated dsa_switch_release_ports function, which should
really be per-switch (free only the members of dst->ports that are also
members of ds, instead of all switch ports).
Signed-off-by: NVladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is possible to stack multiple DSA switches in a way that they are not
part of the tree (disjoint) but the DSA master of a switch is a DSA
slave of another. When that happens switch drivers may have to know this
is the case so as to determine whether their tagging protocol has a
remove chance of working.

This is useful for specific switch drivers such as b53 where devices
have been known to be stacked in the wild without the Broadcom tag
protocol supporting that feature. This allows b53 to continue supporting
those devices by forcing the disabling of Broadcom tags on the outermost
switches if necessary.

The get_tag_protocol() function is therefore updated to gain an
additional enum dsa_tag_protocol argument which denotes the current
tagging protocol used by the DSA master we are attached to, else
DSA_TAG_PROTO_NONE for the top of the dsa_switch_tree.
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

dsa_link_touch() is not exported, or defined outside of the
file it is in so make it static to avoid the following warning:

net/dsa/dsa2.c:127:17: warning: symbol 'dsa_link_touch' was not declared. Should it be static?
Signed-off-by: NBen Dooks (Codethink) <ben.dooks@codethink.co.uk>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The order in which the ports are deleted from the list and freed and the
call to dsa_switch_remove() is done is reversed, which leads to an
use after free condition. Reverse the two: first tear down the ports and
switch from the fabric, then free the ports associated with that switch
fabric.

Fixes: 05f294a8 ("net: dsa: allocate ports on touch")
Signed-off-by: NFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Because there is no static array describing the links between switches
anymore, we have no reason to force a limitation of the index value
set by the device tree.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The DSA fabric setup code has been simplified a lot so get rid of
the dsa_tree_remove_switch, dsa_tree_add_switch and dsa_switch_add
helpers, and keep the code simple with only the dsa_switch_probe and
dsa_switch_remove functions.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that the DSA ports are listed in the switch fabric, there is
no need to store the dsa_switch structures from the drivers in the
fabric anymore. So get rid of the dst->ds static array.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The dsa_switch structure has no routing table specific data to setup,
so the switch fabric can directly walk its ports and initialize its
routing table from them.

This allows us to remove the dsa_switch_setup_routing_table function.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Drivers do not use the ds->rtable static arrays anymore, get rid of it.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Implement a new list of DSA links in the switch fabric itself, to
provide an alterative to the ds->rtable static arrays.

At the same time, provide a new dsa_routing_port() helper to abstract
the usage of ds->rtable in drivers. If there's no port to reach a
given device, return the first invalid port, ds->num_ports. This avoids
potential signedness errors or the need to define special values.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add plumbing to allow DSA drivers to register parameters with devlink.

To keep with the abstraction, the DSA drivers pass the ds structure to
these helpers, and the DSA core then translates that to the devlink
structure associated to the device.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Currently ds->dev is dereferenced on the assignments of pdata and
np before ds->dev is null checked, hence there is a potential null
pointer dereference on ds->dev.  Fix this by assigning pdata and
np after the ds->dev null pointer sanity check.

Addresses-Coverity: ("Dereference before null check")
Fixes: 7e99e347 ("net: dsa: remove dsa_switch_alloc helper")
Signed-off-by: NColin Ian King <colin.king@canonical.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Reported-by: Nkbuild test robot <lkp@intel.com>
Reported-by: NDan Carpenter <dan.carpenter@oracle.com>
Reviewed-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that ports are dynamically listed in the fabric, there is no need
to provide a special helper to allocate the dsa_switch structure. This
will give more flexibility to drivers to embed this structure as they
wish in their private structure.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>

Allocate the struct dsa_port the first time it is accessed with
dsa_port_touch, and remove the static dsa_port array from the
dsa_switch structure.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>

Use the new ports list instead of iterating over switches and their
ports when setting up the default CPU port. Unassign it on teardown.

Now that we can iterate over multiple CPU ports, remove dst->cpu_dp.

At the same time, provide a better error message for CPU-less tree.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>

Use the new ports list instead of iterating over switches and their
ports when looking up the first CPU port in the tree.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>

Now that we have a potential list of CPU ports, make use of it instead
of only configuring the master device of an unique CPU port.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>

Use the new ports list instead of iterating over switches and their
ports to find a port from a given node.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>

Use the new ports list instead of accessing the dsa_switch array
of ports when iterating over DSA ports of a switch to set up the
routing table.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>

Use the new ports list instead of iterating over switches and their
ports when setting up the switches and their ports.

At the same time, provide setup states and messages for ports and
switches as it is done for the trees.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>

Add a list of switch ports within the switch fabric. This will help the
lookup of a port inside the whole fabric, and it is the first step
towards supporting multiple CPU ports, before deprecating the usage of
the unique dst->cpu_dp pointer.

In preparation for a future allocation of the dsa_port structures,
return -ENOMEM in case no structure is returned, even though this
error cannot be reached yet.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>

Do not let the drivers access the ds->ports static array directly
while there is a dsa_to_port helper for this purpose.

At the same time, un-const this helper since the SJA1105 driver
assigns the priv member of the returned dsa_port structure.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NJakub Kicinski <jakub.kicinski@netronome.com>

If there are multiple switch trees on the device, only the last one
will be listed, because the arguments of list_add_tail are swapped.

Fixes: 83c0afae ("net: dsa: Add new binding implementation")
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The DSA core, DSA taggers and DSA drivers all make use of
module_init(). Hence they get initialised at device_initcall() time.
The ordering is non-deterministic. It can be a DSA driver is bound to
a device before the needed tag driver has been initialised, resulting
in the message:

No tagger for this switch

Rather than have this be fatal, return -EPROBE_DEFER so that it is
tried again later once all the needed drivers have been loaded.

Fixes: d3b8c049 ("dsa: Add boilerplate helper to register DSA tag driver modules")
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a function such as dsa_slave_create fails, currently the following
stack trace can be seen:

[    2.038342] sja1105 spi0.1: Probed switch chip: SJA1105T
[    2.054556] sja1105 spi0.1: Reset switch and programmed static config
[    2.063837] sja1105 spi0.1: Enabled switch tagging
[    2.068706] fsl-gianfar soc:ethernet@2d90000 eth2: error -19 setting up slave phy
[    2.076371] ------------[ cut here ]------------
[    2.080973] WARNING: CPU: 1 PID: 21 at net/core/devlink.c:6184 devlink_free+0x1b4/0x1c0
[    2.088954] Modules linked in:
[    2.092005] CPU: 1 PID: 21 Comm: kworker/1:1 Not tainted 5.3.0-rc6-01360-g41b52e38d2b6-dirty #1746
[    2.100912] Hardware name: Freescale LS1021A
[    2.105162] Workqueue: events deferred_probe_work_func
[    2.110287] [<c03133a4>] (unwind_backtrace) from [<c030d8cc>] (show_stack+0x10/0x14)
[    2.117992] [<c030d8cc>] (show_stack) from [<c10b08d8>] (dump_stack+0xb4/0xc8)
[    2.125180] [<c10b08d8>] (dump_stack) from [<c0349d04>] (__warn+0xe0/0xf8)
[    2.132018] [<c0349d04>] (__warn) from [<c0349e34>] (warn_slowpath_null+0x40/0x48)
[    2.139549] [<c0349e34>] (warn_slowpath_null) from [<c0f19d74>] (devlink_free+0x1b4/0x1c0)
[    2.147772] [<c0f19d74>] (devlink_free) from [<c1064fc0>] (dsa_switch_teardown+0x60/0x6c)
[    2.155907] [<c1064fc0>] (dsa_switch_teardown) from [<c1065950>] (dsa_register_switch+0x8e4/0xaa8)
[    2.164821] [<c1065950>] (dsa_register_switch) from [<c0ba7fe4>] (sja1105_probe+0x21c/0x2ec)
[    2.173216] [<c0ba7fe4>] (sja1105_probe) from [<c0b35948>] (spi_drv_probe+0x80/0xa4)
[    2.180920] [<c0b35948>] (spi_drv_probe) from [<c0a4c1cc>] (really_probe+0x108/0x400)
[    2.188711] [<c0a4c1cc>] (really_probe) from [<c0a4c694>] (driver_probe_device+0x78/0x1bc)
[    2.196933] [<c0a4c694>] (driver_probe_device) from [<c0a4a3dc>] (bus_for_each_drv+0x58/0xb8)
[    2.205414] [<c0a4a3dc>] (bus_for_each_drv) from [<c0a4c024>] (__device_attach+0xd0/0x168)
[    2.213637] [<c0a4c024>] (__device_attach) from [<c0a4b1d0>] (bus_probe_device+0x84/0x8c)
[    2.221772] [<c0a4b1d0>] (bus_probe_device) from [<c0a4b72c>] (deferred_probe_work_func+0x84/0xc4)
[    2.230686] [<c0a4b72c>] (deferred_probe_work_func) from [<c03650a4>] (process_one_work+0x218/0x510)
[    2.239772] [<c03650a4>] (process_one_work) from [<c03660d8>] (worker_thread+0x2a8/0x5c0)
[    2.247908] [<c03660d8>] (worker_thread) from [<c036b348>] (kthread+0x148/0x150)
[    2.255265] [<c036b348>] (kthread) from [<c03010e8>] (ret_from_fork+0x14/0x2c)
[    2.262444] Exception stack(0xea965fb0 to 0xea965ff8)
[    2.267466] 5fa0:                                     00000000 00000000 00000000 00000000
[    2.275598] 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[    2.283729] 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
[    2.290333] ---[ end trace ca5d506728a0581a ]---

devlink_free is complaining right here:

	WARN_ON(!list_empty(&devlink->port_list));

This happens because devlink_port_unregister is no longer done right
away in dsa_port_setup when a DSA_PORT_TYPE_USER has failed.
Vivien said about this change that:

    Also no need to call devlink_port_unregister from within dsa_port_setup
    as this step is inconditionally handled by dsa_port_teardown on error.

which is not really true. The devlink_port_unregister function _is_
being called unconditionally from within dsa_port_setup, but not for
this port that just failed, just for the previous ones which were set
up.

ports_teardown:
	for (i = 0; i < port; i++)
		dsa_port_teardown(&ds->ports[i]);

Initially I was tempted to fix this by extending the "for" loop to also
cover the port that failed during setup. But this could have potentially
unforeseen consequences unrelated to devlink_port or even other types of
ports than user ports, which I can't really test for. For example, if
for some reason devlink_port_register itself would fail, then
unconditionally unregistering it in dsa_port_teardown would not be a
smart idea. The list might go on.

So just make dsa_port_setup undo the setup it had done upon failure, and
let the for loop undo the work of setting up the previous ports, which
are guaranteed to be brought up to a consistent state.

Fixes: 955222ca ("net: dsa: use a single switch statement for port setup")
Signed-off-by: NVladimir Oltean <olteanv@gmail.com>
Reviewed-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The bitmap operations were introduced to simplify the switch drivers
in the future, since most of them could implement the common VLAN and
MDB operations (add, del, dump) with simple functions taking all target
ports at once, and thus limiting the number of hardware accesses.

Programming an MDB or VLAN this way in a single operation would clearly
simplify the drivers a lot but would require a new get-set interface
in DSA. The usage of such bitmap from the stack also raised concerned
in the past, leading to the dynamic allocation of a new ds->_bitmap
member in the dsa_switch structure. So let's get rid of them for now.

This commit nicely wraps the ds->ops->port_{mdb,vlan}_{prepare,add}
switch operations into new dsa_switch_{mdb,vlan}_{prepare,add}
variants not using any bitmap argument anymore.

New dsa_switch_{mdb,vlan}_match helpers have been introduced to make
clear which local port of a switch must be programmed with the target
object. While the targeted user port is an obvious candidate, the
DSA links must also be programmed, as well as the CPU port for VLANs.

While at it, also remove local variables that are only used once.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Call the .port_enable and .port_disable functions for all ports,
not only the user ports, so that drivers may optimize the power
consumption of all ports after a successful setup.

Unused ports are now disabled on setup. CPU and DSA ports are now
enabled on setup and disabled on teardown. User ports were already
enabled at slave creation and disabled at slave destruction.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

It is currently difficult to read the different steps involved in the
setup and teardown of ports in the DSA code. Keep it simple with a
single switch statement for each port type: UNUSED, CPU, DSA, or USER.

Also no need to call devlink_port_unregister from within dsa_port_setup
as this step is inconditionally handled by dsa_port_teardown on error.
Signed-off-by: NVivien Didelot <vivien.didelot@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is helpful for e.g. draining per-driver (not per-port) tagger
queues.
Signed-off-by: NVladimir Oltean <olteanv@gmail.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

In case a call to dsa_tree_setup() fails, an attempt to cleanup is made
by calling dsa_tree_remove_switch(), which should take care of
removing/unregistering any resources previously allocated. This does not
happen because it is conditioned by dst->setup being true, which is set
only after _all_ setup steps were performed successfully.

This is especially interesting when the internal MDIO bus is registered
but afterwards, a port setup fails and the mdiobus_unregister() is never
called. This leads to a BUG_ON() complaining about the fact that it's
trying to free an MDIO bus that's still registered.

Add proper error handling in all functions branching from
dsa_tree_setup().
Signed-off-by: NIoana Ciornei <ioana.ciornei@nxp.com>
Reported-by: Nkernel test robot <rong.a.chen@intel.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

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

Frames get processed by DSA and redirected to switch port net devices
based on the ETH_P_XDSA multiplexed packet_type handler found by the
network stack when calling eth_type_trans().

The running assumption is that once the DSA .rcv function is called, DSA
is always able to decode the switch tag in order to change the skb->dev
from its master.

However there are tagging protocols (such as the new DSA_TAG_PROTO_SJA1105,
user of DSA_TAG_PROTO_8021Q) where this assumption is not completely
true, since switch tagging piggybacks on the absence of a vlan_filtering
bridge. Moreover, management traffic (BPDU, PTP) for this switch doesn't
rely on switch tagging, but on a different mechanism. So it would make
sense to at least be able to terminate that.

Having DSA receive traffic it can't decode would put it in an impossible
situation: the eth_type_trans() function would invoke the DSA .rcv(),
which could not change skb->dev, then eth_type_trans() would be invoked
again, which again would call the DSA .rcv, and the packet would never
be able to exit the DSA filter and would spiral in a loop until the
whole system dies.

This happens because eth_type_trans() doesn't actually look at the skb
(so as to identify a potential tag) when it deems it as being
ETH_P_XDSA. It just checks whether skb->dev has a DSA private pointer
installed (therefore it's a DSA master) and that there exists a .rcv
callback (everybody except DSA_TAG_PROTO_NONE has that). This is
understandable as there are many switch tags out there, and exhaustively
checking for all of them is far from ideal.

The solution lies in introducing a filtering function for each tagging
protocol. In the absence of a filtering function, all traffic is passed
to the .rcv DSA callback. The tagging protocol should see the filtering
function as a pre-validation that it can decode the incoming skb. The
traffic that doesn't match the filter will bypass the DSA .rcv callback
and be left on the master netdevice, which wasn't previously possible.
Signed-off-by: NVladimir Oltean <olteanv@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This allows the driver to perform some manipulations of its own during
setup, using generic switchdev calls. Having the notifiers registered at
setup time is important because otherwise any switchdev transaction
emitted during this time would be ignored (dispatched to an empty call
chain).

One current usage scenario is for the driver to request DSA to set up
802.1Q based switch tagging for its ports.

There is no danger for the driver setup code to start racing now with
switchdev events emitted from the network stack (such as bridge core)
even if the notifier is registered earlier. This is because the network
stack needs a net_device as a vehicle to perform switchdev operations,
and the slave net_devices are registered later than the core driver
setup anyway (ds->ops->setup in dsa_switch_setup vs dsa_port_setup).

Luckily DSA doesn't need a net_device to carry out switchdev callbacks,
and therefore drivers shouldn't assume either that net_devices are
available at the time their switchdev callbacks get invoked.
Signed-off-by: NVladimir Oltean <olteanv@gmail.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Reviewed-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: Vivien Didelot <vivien.didelot@gmail.com>-
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

When a DSA switch driver is unloaded, the lock on the tag driver
should be released so the module can be unloaded. Add the needed calls,
but leave the actual release code as a stub.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>

v2
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

dsa_resolve_tag_protocol() is used to find the tagging driver needed
by a switch driver. When the tagging drivers become modules, it will
be necassary to take a reference on the module to prevent it being
unloaded. So rename this function to _get() to indicate it has some
locking properties.
Signed-off-by: NAndrew Lunn <andrew@lunn.ch>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pass the switch ID down the to devlink through devlink_port_attrs_set()
so it can be used by devlink_compat_switch_id_get(). Leave
ndo_get_port_parent_id implementation only for legacy.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Reviewed-by: NFlorian Fainelli <f.fainelli@gmail.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Extend devlink_port_attrs_set() to pass switch ID for ports which are
part of switch and store it in port attrs. For other ports, this is
NULL.

Note that this allows the driver to group devlink ports into one or more
switches according to the actual topology.
Signed-off-by: NJiri Pirko <jiri@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Before creating a slave netdevice, get the mac address from DTS and
apply in case it is valid.
Signed-off-by: NXiaofei Shen <xiaofeis@codeaurora.org>
Signed-off-by: NVinod Koul <vkoul@kernel.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>