Given that standalone ports are now configured to bypass the ATU and
forward all frames towards the upstream port, extend the ATU bypass to
multichip systems.
Load VID 0 (standalone) into the VTU with the policy bit set. Since
VID 4095 (bridged) is already loaded, we now know that all VIDs in use
are always available in all VTUs. Therefore, we can safely enable
802.1Q on DSA ports.
Setting the DSA ports' VTU policy to TRAP means that all incoming
frames on VID 0 will be classified as MGMT - as a result, the ATU is
bypassed on all subsequent switches.
With this isolation in place, we are able to support configurations
that are simultaneously very quirky and very useful. Quirky because it
involves looping cables between local switchports like in this
example:
CPU
| .------.
.---0---. | .----0----.
| sw0 | | | sw1 |
'-1-2-3-' | '-1-2-3-4-'
$ @ '---' $ @ % %
We have three physically looped pairs ($, @, and %).
This is very useful because it allows us to run the kernel's
kselftests for the bridge on mv88e6xxx hardware.
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Clear MapDA on standalone ports to bypass any ATU lookup that might
point the packet in the wrong direction. This means that all packets
are flooded using the PVT config. So make sure that standalone ports
are only allowed to communicate with the local upstream port.
Here is a scenario in which this is needed:
CPU
| .----.
.---0---. | .--0--.
| sw0 | | | sw1 |
'-1-2-3-' | '-1-2-'
'---'
- sw0p1 and sw1p1 are bridged
- sw0p2 and sw1p2 are in standalone mode
- Learning must be enabled on sw0p3 in order for hardware forwarding
to work properly between bridged ports
1. A packet with SA :aa comes in on sw1p2
1a. Egresses sw1p0
1b. Ingresses sw0p3, ATU adds an entry for :aa towards port 3
1c. Egresses sw0p0
2. A packet with DA :aa comes in on sw0p2
2a. If an ATU lookup is done at this point, the packet will be
incorrectly forwarded towards sw0p3. With this change in place,
the ATU is bypassed and the packet is forwarded in accordance
with the PVT, which only contains the CPU port.
Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Certain drivers may need to send management traffic to the switch for
things like register access, FDB dump, etc, to accelerate what their
slow bus (SPI, I2C, MDIO) can already do.
Ethernet is faster (especially in bulk transactions) but is also more
unreliable, since the user may decide to bring the DSA master down (or
not bring it up), therefore severing the link between the host and the
attached switch.
Drivers needing Ethernet-based register access already should have
fallback logic to the slow bus if the Ethernet method fails, but that
fallback may be based on a timeout, and the I/O to the switch may slow
down to a halt if the master is down, because every Ethernet packet will
have to time out. The driver also doesn't have the option to turn off
Ethernet-based I/O momentarily, because it wouldn't know when to turn it
back on.
Which is where this change comes in. By tracking NETDEV_CHANGE,
NETDEV_UP and NETDEV_GOING_DOWN events on the DSA master, we should know
the exact interval of time during which this interface is reliably
available for traffic. Provide this information to switches so they can
use it as they wish.
An helper is added dsa_port_master_is_operational() to check if a master
port is operational.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
As discussed during review here:
https://patchwork.kernel.org/project/netdevbpf/patch/20220105132141.2648876-3-vladimir.oltean@nxp.com/
we should inform developers about pitfalls of concurrent access to the
boolean properties of dsa_switch and dsa_port, now that they've been
converted to bit fields. No other measure than a comment needs to be
taken, since the code paths that update these bit fields are not
concurrent with each other.
Suggested-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is a cosmetic incremental fixup to commits
7787ff7763 ("net: dsa: merge all bools of struct dsa_switch into a single u32")
bde82f389a ("net: dsa: merge all bools of struct dsa_port into a single u8")
The desire to make this change was enunciated after posting these
patches here:
https://patchwork.kernel.org/project/netdevbpf/cover/20220105132141.2648876-1-vladimir.oltean@nxp.com/
but due to a slight timing overlap (message posted at 2:28 p.m. UTC,
merge commit is at 2:46 p.m. UTC), that comment was missed and the
changes were applied as-is.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
On the NXP Bluebox 3 board which uses a multi-switch setup with sja1105,
the mechanism through which the tagger connects to the switch tree is
broken, due to improper DSA code design. At the time when tag_ops->connect()
is called in dsa_port_parse_cpu(), DSA hasn't finished "touching" all
the ports, so it doesn't know how large the tree is and how many ports
it has. It has just seen the first CPU port by this time. As a result,
this function will call the tagger's ->connect method too early, and the
tagger will connect only to the first switch from the tree.
This could be perhaps addressed a bit more simply by just moving the
tag_ops->connect(dst) call a bit later (for example in dsa_tree_setup),
but there is already a design inconsistency at present: on the switch
side, the notification is on a per-switch basis, but on the tagger side,
it is on a per-tree basis. Furthermore, the persistent storage itself is
per switch (ds->tagger_data). And the tagger connect and disconnect
procedures (at least the ones that exist currently) could see a fair bit
of simplification if they didn't have to iterate through the switches of
a tree.
To fix the issue, this change transforms tag_ops->connect(dst) into
tag_ops->connect(ds) and moves it somewhere where we already iterate
over all switches of a tree. That is in dsa_switch_setup_tag_protocol(),
which is a good placement because we already have there the connection
call to the switch side of things.
As for the dsa_tree_bind_tag_proto() method (called from the code path
that changes the tag protocol), things are a bit more complicated
because we receive the tree as argument, yet when we unwind on errors,
it would be nice to not call tag_ops->disconnect(ds) where we didn't
previously call tag_ops->connect(ds). We didn't have this problem before
because the tag_ops connection operations passed the entire dst before,
and this is more fine grained now. To solve the error rewind case using
the new API, we have to create yet one more cross-chip notifier for
disconnection, and stay connected with the old tag protocol to all the
switches in the tree until we've succeeded to connect with the new one
as well. So if something fails half way, the whole tree is still
connected to the old tagger. But there may still be leaks if the tagger
fails to connect to the 2nd out of 3 switches in a tree: somebody needs
to tell the tagger to disconnect from the first switch. Nothing comes
for free, and this was previously handled privately by the tagging
protocol driver before, but now we need to emit a disconnect cross-chip
notifier for that, because DSA has to take care of the unwind path. We
assume that the tagging protocol has connected to a switch if it has set
ds->tagger_data to something, otherwise we avoid calling its
disconnection method in the error rewind path.
The rest of the changes are in the tagging protocol drivers, and have to
do with the replacement of dst with ds. The iteration is removed and the
error unwind path is simplified, as mentioned above.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
All current in-tree uses of dp->priv have been replaced with
ds->tagger_data, which provides for a safer API especially when the
connection isn't the regular 1:1 link between one switch driver and one
tagging protocol driver, but could be either one switch to many taggers,
or many switches to one tagger.
Therefore, we can remove this unused pointer.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Ansuel is working on register access over Ethernet for the qca8k switch
family. This requires the qca8k tagging protocol driver to receive
frames which aren't intended for the network stack, but instead for the
qca8k switch driver itself.
The dp->priv is currently the prevailing method for passing data back
and forth between the tagging protocol driver and the switch driver.
However, this method is riddled with caveats.
The DSA design allows in principle for any switch driver to return any
protocol it desires in ->get_tag_protocol(). The dsa_loop driver can be
modified to do just that. But in the current design, the memory behind
dp->priv has to be allocated by the switch driver, so if the tagging
protocol is paired to an unexpected switch driver, we may end up in NULL
pointer dereferences inside the kernel, or worse (a switch driver may
allocate dp->priv according to the expectations of a different tagger).
The latter possibility is even more plausible considering that DSA
switches can dynamically change tagging protocols in certain cases
(dsa <-> edsa, ocelot <-> ocelot-8021q), and the current design lends
itself to mistakes that are all too easy to make.
This patch proposes that the tagging protocol driver should manage its
own memory, instead of relying on the switch driver to do so.
After analyzing the different in-tree needs, it can be observed that the
required tagger storage is per switch, therefore a ds->tagger_data
pointer is introduced. In principle, per-port storage could also be
introduced, although there is no need for it at the moment. Future
changes will replace the current usage of dp->priv with ds->tagger_data.
We define a "binding" event between the DSA switch tree and the tagging
protocol. During this binding event, the tagging protocol's ->connect()
method is called first, and this may allocate some memory for each
switch of the tree. Then a cross-chip notifier is emitted for the
switches within that tree, and they are given the opportunity to fix up
the tagger's memory (for example, they might set up some function
pointers that represent virtual methods for consuming packets).
Because the memory is owned by the tagger, there exists a ->disconnect()
method for the tagger (which is the place to free the resources), but
there doesn't exist a ->disconnect() method for the switch driver.
This is part of the design. The switch driver should make minimal use of
the public part of the tagger data, and only after type-checking it
using the supplied "proto" argument.
In the code there are in fact two binding events, one is the initial
event in dsa_switch_setup_tag_protocol(). At this stage, the cross chip
notifier chains aren't initialized, so we call each switch's connect()
method by hand. Then there is dsa_tree_bind_tag_proto() during
dsa_tree_change_tag_proto(), and here we have an old protocol and a new
one. We first connect to the new one before disconnecting from the old
one, to simplify error handling a bit and to ensure we remain in a valid
state at all times.
Co-developed-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: Ansuel Smith <ansuelsmth@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
We don't really need new switch API for these, and with new switches
which intend to add support for this feature, it will become cumbersome
to maintain.
The change consists in restructuring the two drivers that implement this
offload (sja1105 and mv88e6xxx) such that the offload is enabled and
disabled from the ->port_bridge_{join,leave} methods instead of the old
->port_bridge_tx_fwd_{,un}offload.
The only non-trivial change is that mv88e6xxx_map_virtual_bridge_to_pvt()
has been moved to avoid a forward declaration, and the
mv88e6xxx_reg_lock() calls from inside it have been removed, since
locking is now done from mv88e6xxx_port_bridge_{join,leave}.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This is a preparation patch for the removal of the DSA switch methods
->port_bridge_tx_fwd_offload() and ->port_bridge_tx_fwd_unoffload().
The plan is for the switch to report whether it offloads TX forwarding
directly as a response to the ->port_bridge_join() method.
This change deals with the noisy portion of converting all existing
function prototypes to take this new boolean pointer argument.
The bool is placed in the cross-chip notifier structure for bridge join,
and a reference to it is provided to drivers. In the next change, DSA
will then actually look at this value instead of calling
->port_bridge_tx_fwd_offload().
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The main desire behind this is to provide coherent bridge information to
the fast path without locking.
For example, right now we set dp->bridge_dev and dp->bridge_num from
separate code paths, it is theoretically possible for a packet
transmission to read these two port properties consecutively and find a
bridge number which does not correspond with the bridge device.
Another desire is to start passing more complex bridge information to
dsa_switch_ops functions. For example, with FDB isolation, it is
expected that drivers will need to be passed the bridge which requested
an FDB/MDB entry to be offloaded, and along with that bridge_dev, the
associated bridge_num should be passed too, in case the driver might
want to implement an isolation scheme based on that number.
We already pass the {bridge_dev, bridge_num} pair to the TX forwarding
offload switch API, however we'd like to remove that and squash it into
the basic bridge join/leave API. So that means we need to pass this
pair to the bridge join/leave API.
During dsa_port_bridge_leave, first we unset dp->bridge_dev, then we
call the driver's .port_bridge_leave with what used to be our
dp->bridge_dev, but provided as an argument.
When bridge_dev and bridge_num get folded into a single structure, we
need to preserve this behavior in dsa_port_bridge_leave: we need a copy
of what used to be in dp->bridge.
Switch drivers check bridge membership by comparing dp->bridge_dev with
the provided bridge_dev, but now, if we provide the struct dsa_bridge as
a pointer, they cannot keep comparing dp->bridge to the provided
pointer, since this only points to an on-stack copy. To make this
obvious and prevent driver writers from forgetting and doing stupid
things, in this new API, the struct dsa_bridge is provided as a full
structure (not very large, contains an int and a pointer) instead of a
pointer. An explicit comparison function needs to be used to determine
bridge membership: dsa_port_offloads_bridge().
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Move the static inline helpers from net/dsa/dsa_priv.h to
include/net/dsa.h, so that drivers can call functions such as
dsa_port_offloads_bridge_dev(), which will be necessary after the
transition to a more complex bridge structure.
More functions than are needed right now are being moved, but this is
done for uniformity.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The location of the bridge device pointer and number is going to change.
It is not going to be kept individually per port, but in a common
structure allocated dynamically and which will have lockdep validation.
Create helpers to access these elements so that we have a migration path
to the new organization.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
The service where DSA assigns a unique bridge number for each forwarding
domain is useful even for drivers which do not implement the TX
forwarding offload feature.
For example, drivers might use the dp->bridge_num for FDB isolation.
So rename ds->num_fwd_offloading_bridges to ds->max_num_bridges, and
calculate a unique bridge_num for all drivers that set this value.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
I have seen too many bugs already due to the fact that we must encode an
invalid dp->bridge_num as a negative value, because the natural tendency
is to check that invalid value using (!dp->bridge_num). Latest example
can be seen in commit 1bec0f0506 ("net: dsa: fix bridge_num not
getting cleared after ports leaving the bridge").
Convert the existing users to assume that dp->bridge_num == 0 is the
encoding for invalid, and valid bridge numbers start from 1.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Phylink needs slightly more information than phylink_get_interfaces()
allows us to get from the DSA drivers - we need the MAC capabilities.
Replace the phylink_get_interfaces() method with phylink_get_caps() to
allow DSA drivers to fill in the phylink_config MAC capabilities field
as well.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Marek Behún <kabel@kernel.org>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Add a new DSA switch operation, phylink_get_interfaces, which should
fill in which PHY_INTERFACE_MODE_* are supported by given port.
Use this before phylink_create() to fill phylinks supported_interfaces
member, allowing phylink to determine which PHY_INTERFACE_MODEs are
supported.
Signed-off-by: Marek Behún <kabel@kernel.org>
[tweaked patch and description to add more complete support -- rmk]
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that the rtnl_mutex is going away for dsa_port_{host_,}fdb_{add,del},
no one is serializing access to the address lists that DSA keeps for the
purpose of reference counting on shared ports (CPU and cascade ports).
It can happen for one dsa_switch_do_fdb_del to do list_del on a dp->fdbs
element while another dsa_switch_do_fdb_{add,del} is traversing dp->fdbs.
We need to avoid that.
Currently dp->mdbs is not at risk, because dsa_switch_do_mdb_{add,del}
still runs under the rtnl_mutex. But it would be nice if it would not
depend on that being the case. So let's introduce a mutex per port (the
address lists are per port too) and share it between dp->mdbs and
dp->fdbs.
The place where we put the locking is interesting. It could be tempting
to put a DSA-level lock which still serializes calls to
.port_fdb_{add,del}, but it would still not avoid concurrency with other
driver code paths that are currently under rtnl_mutex (.port_fdb_dump,
.port_fast_age). So it would add a very false sense of security (and
adding a global switch-wide lock in DSA to resynchronize with the
rtnl_lock is also counterproductive and hard).
So the locking is intentionally done only where the dp->fdbs and dp->mdbs
lists are traversed. That means, from a driver perspective, that
.port_fdb_add will be called with the dp->addr_lists_lock mutex held on
the CPU port, but not held on user ports. This is done so that driver
writers are not encouraged to rely on any guarantee offered by
dp->addr_lists_lock.
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>
Now that the rtnl_mutex is going away for dsa_port_{host_,}fdb_{add,del},
no one is serializing access to the address lists that DSA keeps for the
purpose of reference counting on shared ports (CPU and cascade ports).
It can happen for one dsa_switch_do_fdb_del to do list_del on a dp->fdbs
element while another dsa_switch_do_fdb_{add,del} is traversing dp->fdbs.
We need to avoid that.
Currently dp->mdbs is not at risk, because dsa_switch_do_mdb_{add,del}
still runs under the rtnl_mutex. But it would be nice if it would not
depend on that being the case. So let's introduce a mutex per port (the
address lists are per port too) and share it between dp->mdbs and
dp->fdbs.
The place where we put the locking is interesting. It could be tempting
to put a DSA-level lock which still serializes calls to
.port_fdb_{add,del}, but it would still not avoid concurrency with other
driver code paths that are currently under rtnl_mutex (.port_fdb_dump,
.port_fast_age). So it would add a very false sense of security (and
adding a global switch-wide lock in DSA to resynchronize with the
rtnl_lock is also counterproductive and hard).
So the locking is intentionally done only where the dp->fdbs and dp->mdbs
lists are traversed. That means, from a driver perspective, that
.port_fdb_add will be called with the dp->addr_lists_lock mutex held on
the CPU port, but not held on user ports. This is done so that driver
writers are not encouraged to rely on any guarantee offered by
dp->addr_lists_lock.
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>
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>
Since the DSA conversion from the ds->ports array into the dst->ports
list, the DSA API has encouraged driver writers, as well as the core
itself, to write inefficient code.
Currently, code that wants to filter by a specific type of port when
iterating, like {!unused, user, cpu, dsa}, uses the dsa_is_*_port helper.
Under the hood, this uses dsa_to_port which iterates again through
dst->ports. But the driver iterates through the port list already, so
the complexity is quadratic for the typical case of a single-switch
tree.
This patch introduces some iteration helpers where the iterator is
already a struct dsa_port *dp, so that the other variant of the
filtering functions, dsa_port_is_{unused,user,cpu_dsa}, can be used
directly on the iterator. This eliminates the second lookup.
These functions can be used both by the core and by drivers.
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>
This commit implements a basic version of the 8 byte tag protocol used
in the Realtek RTL8365MB-VC unmanaged switch, which carries with it a
protocol version of 0x04.
The implementation itself only handles the parsing of the EtherType
value and Realtek protocol version, together with the source or
destination port fields. The rest is left unimplemented for now.
The tag format is described in a confidential document provided to my
company by Realtek Semiconductor Corp. Permission has been granted by
the vendor to publish this driver based on that material, together with
an extract from the document describing the tag format and its fields.
It is hoped that this will help future implementors who do not have
access to the material but who wish to extend the functionality of
drivers for chips which use this protocol.
In addition, two possible values of the REASON field are specified,
based on experiments on my end. Realtek does not specify what value this
field can take.
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Tested-by: Arınç ÜNAL <arinc.unal@arinc9.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Jakub pointed out that we have a new ethtool API for reporting device
statistics in a standardized way, via .get_eth_{phy,mac,ctrl}_stats.
Add a small amount of plumbing to allow DSA drivers to take advantage of
this when exposing statistics.
Suggested-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 86f8b1c01a ("net: dsa: Do not make user port errors fatal")
decided it was fine to ignore errors on certain ports that fail to
probe, and go on with the ports that do probe fine.
Commit fb6ec87f72 ("net: dsa: Fix type was not set for devlink port")
noticed that devlink_port_type_eth_set(dlp, dp->slave); does not get
called, and devlink notices after a timeout of 3600 seconds and prints a
WARN_ON. So it went ahead to unregister the devlink port. And because
there exists an UNUSED port flavour, we actually re-register the devlink
port as UNUSED.
Commit 08156ba430 ("net: dsa: Add devlink port regions support to
DSA") added devlink port regions, which are set up by the driver and not
by DSA.
When we trigger the devlink port deregistration and reregistration as
unused, devlink now prints another WARN_ON, from here:
devlink_port_unregister:
WARN_ON(!list_empty(&devlink_port->region_list));
So the port still has regions, which makes sense, because they were set
up by the driver, and the driver doesn't know we're unregistering the
devlink port.
Somebody needs to tear them down, and optionally (actually it would be
nice, to be consistent) set them up again for the new devlink port.
But DSA's layering stays in our way quite badly here.
The options I've considered are:
1. Introduce a function in devlink to just change a port's type and
flavour. No dice, devlink keeps a lot of state, it really wants the
port to not be registered when you set its parameters, so changing
anything can only be done by destroying what we currently have and
recreating it.
2. Make DSA cache the parameters passed to dsa_devlink_port_region_create,
and the region returned, keep those in a list, then when the devlink
port unregister needs to take place, the existing devlink regions are
destroyed by DSA, and we replay the creation of new regions using the
cached parameters. Problem: mv88e6xxx keeps the region pointers in
chip->ports[port].region, and these will remain stale after DSA frees
them. There are many things DSA can do, but updating mv88e6xxx's
private pointers is not one of them.
3. Just let the driver do it (i.e. introduce a very specific method
called ds->ops->port_reinit_as_unused, which unregisters its devlink
port devlink regions, then the old devlink port, then registers the
new one, then the devlink port regions for it). While it does work,
as opposed to the others, it's pretty horrible from an API
perspective and we can do better.
4. Introduce a new pair of methods, ->port_setup and ->port_teardown,
which in the case of mv88e6xxx must register and unregister the
devlink port regions. Call these 2 methods when the port must be
reinitialized as unused.
Naturally, I went for the 4th approach.
Fixes: 08156ba430 ("net: dsa: Add devlink port regions support to DSA")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Lino reports that on his system with bcmgenet as DSA master and KSZ9897
as a switch, rebooting or shutting down never works properly.
What does the bcmgenet driver have special to trigger this, that other
DSA masters do not? It has an implementation of ->shutdown which simply
calls its ->remove implementation. Otherwise said, it unregisters its
network interface on shutdown.
This message can be seen in a loop, and it hangs the reboot process there:
unregister_netdevice: waiting for eth0 to become free. Usage count = 3
So why 3?
A usage count of 1 is normal for a registered network interface, and any
virtual interface which links itself as an upper of that will increment
it via dev_hold. In the case of DSA, this is the call path:
dsa_slave_create
-> netdev_upper_dev_link
-> __netdev_upper_dev_link
-> __netdev_adjacent_dev_insert
-> dev_hold
So a DSA switch with 3 interfaces will result in a usage count elevated
by two, and netdev_wait_allrefs will wait until they have gone away.
Other stacked interfaces, like VLAN, watch NETDEV_UNREGISTER events and
delete themselves, but DSA cannot just vanish and go poof, at most it
can unbind itself from the switch devices, but that must happen strictly
earlier compared to when the DSA master unregisters its net_device, so
reacting on the NETDEV_UNREGISTER event is way too late.
It seems that it is a pretty established pattern to have a driver's
->shutdown hook redirect to its ->remove hook, so the same code is
executed regardless of whether the driver is unbound from the device, or
the system is just shutting down. As Florian puts it, it is quite a big
hammer for bcmgenet to unregister its net_device during shutdown, but
having a common code path with the driver unbind helps ensure it is well
tested.
So DSA, for better or for worse, has to live with that and engage in an
arms race of implementing the ->shutdown hook too, from all individual
drivers, and do something sane when paired with masters that unregister
their net_device there. The only sane thing to do, of course, is to
unlink from the master.
However, complications arise really quickly.
The pattern of redirecting ->shutdown to ->remove is not unique to
bcmgenet or even to net_device drivers. In fact, SPI controllers do it
too (see dspi_shutdown -> dspi_remove), and presumably, I2C controllers
and MDIO controllers do it too (this is something I have not researched
too deeply, but even if this is not the case today, it is certainly
plausible to happen in the future, and must be taken into consideration).
Since DSA switches might be SPI devices, I2C devices, MDIO devices, the
insane implication is that for the exact same DSA switch device, we
might have both ->shutdown and ->remove getting called.
So we need to do something with that insane environment. The pattern
I've come up with is "if this, then not that", so if either ->shutdown
or ->remove gets called, we set the device's drvdata to NULL, and in the
other hook, we check whether the drvdata is NULL and just do nothing.
This is probably not necessary for platform devices, just for devices on
buses, but I would really insist for consistency among drivers, because
when code is copy-pasted, it is not always copy-pasted from the best
sources.
So depending on whether the DSA switch's ->remove or ->shutdown will get
called first, we cannot really guarantee even for the same driver if
rebooting will result in the same code path on all platforms. But
nonetheless, we need to do something minimally reasonable on ->shutdown
too to fix the bug. Of course, the ->remove will do more (a full
teardown of the tree, with all data structures freed, and this is why
the bug was not caught for so long). The new ->shutdown method is kept
separate from dsa_unregister_switch not because we couldn't have
unregistered the switch, but simply in the interest of doing something
quick and to the point.
The big question is: does the DSA switch's ->shutdown get called earlier
than the DSA master's ->shutdown? If not, there is still a risk that we
might still trigger the WARN_ON in unregister_netdevice that says we are
attempting to unregister a net_device which has uppers. That's no good.
Although the reference to the master net_device won't physically go away
even if DSA's ->shutdown comes afterwards, remember we have a dev_hold
on it.
The answer to that question lies in this comment above device_link_add:
* A side effect of the link creation is re-ordering of dpm_list and the
* devices_kset list by moving the consumer device and all devices depending
* on it to the ends of these lists (that does not happen to devices that have
* not been registered when this function is called).
so the fact that DSA uses device_link_add towards its master is not
exactly for nothing. device_shutdown() walks devices_kset from the back,
so this is our guarantee that DSA's shutdown happens before the master's
shutdown.
Fixes: 2f1e8ea726 ("net: dsa: link interfaces with the DSA master to get rid of lockdep warnings")
Link: https://lore.kernel.org/netdev/20210909095324.12978-1-LinoSanfilippo@gmx.de/
Reported-by: Lino Sanfilippo <LinoSanfilippo@gmx.de>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Tested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
Sometimes when unbinding the mv88e6xxx driver on Turris MOX, these error
messages appear:
mv88e6085 d0032004.mdio-mii:12: port 1 failed to delete be:79:b4:9e:9e:96 vid 1 from fdb: -2
mv88e6085 d0032004.mdio-mii:12: port 1 failed to delete be:79:b4:9e:9e:96 vid 0 from fdb: -2
mv88e6085 d0032004.mdio-mii:12: port 1 failed to delete d8:58:d7:00:ca:6d vid 100 from fdb: -2
mv88e6085 d0032004.mdio-mii:12: port 1 failed to delete d8:58:d7:00:ca:6d vid 1 from fdb: -2
mv88e6085 d0032004.mdio-mii:12: port 1 failed to delete d8:58:d7:00:ca:6d vid 0 from fdb: -2
(and similarly for other ports)
What happens is that DSA has a policy "even if there are bugs, let's at
least not leak memory" and dsa_port_teardown() clears the dp->fdbs and
dp->mdbs lists, which are supposed to be empty.
But deleting that cleanup code, the warnings go away.
=> the FDB and MDB lists (used for refcounting on shared ports, aka CPU
and DSA ports) will eventually be empty, but are not empty by the time
we tear down those ports. Aka we are deleting them too soon.
The addresses that DSA complains about are host-trapped addresses: the
local addresses of the ports, and the MAC address of the bridge device.
The problem is that offloading those entries happens from a deferred
work item scheduled by the SWITCHDEV_FDB_DEL_TO_DEVICE handler, and this
races with the teardown of the CPU and DSA ports where the refcounting
is kept.
In fact, not only it races, but fundamentally speaking, if we iterate
through the port list linearly, we might end up tearing down the shared
ports even before we delete a DSA user port which has a bridge upper.
So as it turns out, we need to first tear down the user ports (and the
unused ones, for no better place of doing that), then the shared ports
(the CPU and DSA ports). In between, we need to ensure that all work
items scheduled by our switchdev handlers (which only run for user
ports, hence the reason why we tear them down first) have finished.
Fixes: 161ca59d39 ("net: dsa: reference count the MDB entries at the cross-chip notifier level")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20210914134726.2305133-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
As explained in commit e358bef7c3 ("net: dsa: Give drivers the chance
to veto certain upper devices"), the hellcreek driver uses some tricks
to comply with the network stack expectations: it enforces port
separation in standalone mode using VLANs. For untagged traffic,
bridging between ports is prevented by using different PVIDs, and for
VLAN-tagged traffic, it never accepts 8021q uppers with the same VID on
two ports, so packets with one VLAN cannot leak from one port to another.
That is almost fine*, and has worked because hellcreek relied on an
implicit behavior of the DSA core that was changed by the previous
patch: the standalone ports declare the 'rx-vlan-filter' feature as 'on
[fixed]'. Since most of the DSA drivers are actually VLAN-unaware in
standalone mode, that feature was actually incorrectly reflecting the
hardware/driver state, so there was a desire to fix it. This leaves the
hellcreek driver in a situation where it has to explicitly request this
behavior from the DSA framework.
We configure the ports as follows:
- Standalone: 'rx-vlan-filter' is on. An 8021q upper on top of a
standalone hellcreek port will go through dsa_slave_vlan_rx_add_vid
and will add a VLAN to the hardware tables, giving the driver the
opportunity to refuse it through .port_prechangeupper.
- Bridged with vlan_filtering=0: 'rx-vlan-filter' is off. An 8021q upper
on top of a bridged hellcreek port will not go through
dsa_slave_vlan_rx_add_vid, because there will not be any attempt to
offload this VLAN. The driver already disables VLAN awareness, so that
upper should receive the traffic it needs.
- Bridged with vlan_filtering=1: 'rx-vlan-filter' is on. An 8021q upper
on top of a bridged hellcreek port will call dsa_slave_vlan_rx_add_vid,
and can again be vetoed through .port_prechangeupper.
*It is not actually completely fine, because if I follow through
correctly, we can have the following situation:
ip link add br0 type bridge vlan_filtering 0
ip link set lan0 master br0 # lan0 now becomes VLAN-unaware
ip link set lan0 nomaster # lan0 fails to become VLAN-aware again, therefore breaking isolation
This patch fixes that corner case by extending the DSA core logic, based
on this requested attribute, to change the VLAN awareness state of the
switch (port) when it leaves the bridge.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Kurt Kanzenbach <kurt@linutronix.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
Right now, cross-tree bridging setups work somewhat by mistake.
In the case of cross-tree bridging with sja1105, all switch instances
need to agree upon a common VLAN ID for forwarding a packet that belongs
to a certain bridging domain.
With TX forwarding offload, the VLAN ID is the bridge VLAN for
VLAN-aware bridging, and the tag_8021q TX forwarding offload VID
(a VLAN which has non-zero VBID bits) for VLAN-unaware bridging.
The VBID for VLAN-unaware bridging is derived from the dp->bridge_num
value calculated by DSA independently for each switch tree.
If ports from one tree join one bridge, and ports from another tree join
another bridge, DSA will assign them the same bridge_num, even though
the bridges are different. If cross-tree bridging is supported, this
is an issue.
Modify DSA to calculate the bridge_num globally across all switch trees.
This has the implication for a driver that the dp->bridge_num value that
DSA will assign to its ports might not be contiguous, if there are
boards with multiple DSA drivers instantiated. Additionally, all
bridge_num values eat up towards each switch's
ds->num_fwd_offloading_bridges maximum, which is potentially unfortunate,
and can be seen as a limitation introduced by this patch. However, that
is the lesser evil for now.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that DSA keeps track of the port learning state, it becomes
superfluous to keep an additional variable with this information in the
sja1105 driver. Remove it.
The DSA core's learning state is present in struct dsa_port *dp.
To avoid the antipattern where we iterate through a DSA switch's
ports and then call dsa_to_port to obtain the "dp" reference (which is
bad because dsa_to_port iterates through the DSA switch tree once
again), just iterate through the dst->ports and operate on those
directly.
The sja1105 had an extra use of priv->learn_ena on non-user ports. DSA
does not touch the learning state of those ports - drivers are free to
do what they wish on them. Mark that information with a comment in
struct dsa_port and let sja1105 set dp->learning for cascade ports.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently DSA leaves it down to device drivers to fast age the FDB on a
port when address learning is disabled on it. There are 2 reasons for
doing that in the first place:
- when address learning is disabled by user space, through
IFLA_BRPORT_LEARNING or the brport_attr_learning sysfs, what user
space typically wants to achieve is to operate in a mode with no
dynamic FDB entry on that port. But if the port is already up, some
addresses might have been already learned on it, and it seems silly to
wait for 5 minutes for them to expire until something useful can be
done.
- when a port leaves a bridge and becomes standalone, DSA turns off
address learning on it. This also has the nice side effect of flushing
the dynamically learned bridge FDB entries on it, which is a good idea
because standalone ports should not have bridge FDB entries on them.
We let drivers manage fast ageing under this condition because if DSA
were to do it, it would need to track each port's learning state, and
act upon the transition, which it currently doesn't.
But there are 2 reasons why doing it is better after all:
- drivers might get it wrong and not do it (see b53_port_set_learning)
- we would like to flush the dynamic entries from the software bridge
too, and letting drivers do that would be another pain point
So track the port learning state and trigger a fast age process
automatically within DSA.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Commit 08cc83cc7f ("net: dsa: add support for BRIDGE_MROUTER
attribute") added an option for users to turn off multicast flooding
towards the CPU if they turn off the IGMP querier on a bridge which
already has enslaved ports (echo 0 > /sys/class/net/br0/bridge/multicast_router).
And commit a8b659e7ff ("net: dsa: act as passthrough for bridge port flags")
simply papered over that issue, because it moved the decision to flood
the CPU with multicast (or not) from the DSA core down to individual drivers,
instead of taking a more radical position then.
The truth is that disabling multicast flooding to the CPU is simply
something we are not prepared to do now, if at all. Some reasons:
- ICMP6 neighbor solicitation messages are unregistered multicast
packets as far as the bridge is concerned. So if we stop flooding
multicast, the outside world cannot ping the bridge device's IPv6
link-local address.
- There might be foreign interfaces bridged with our DSA switch ports
(sending a packet towards the host does not necessarily equal
termination, but maybe software forwarding). So if there is no one
interested in that multicast traffic in the local network stack, that
doesn't mean nobody is.
- PTP over L4 (IPv4, IPv6) is multicast, but is unregistered as far as
the bridge is concerned. This should reach the CPU port.
- The switch driver might not do FDB partitioning. And since we don't
even bother to do more fine-grained flood disabling (such as "disable
flooding _from_port_N_ towards the CPU port" as opposed to "disable
flooding _from_any_port_ towards the CPU port"), this breaks standalone
ports, or even multiple bridges where one has an IGMP querier and one
doesn't.
Reverting the logic makes all of the above work.
Fixes: a8b659e7ff ("net: dsa: act as passthrough for bridge port flags")
Fixes: 08cc83cc7f ("net: dsa: add support for BRIDGE_MROUTER attribute")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Most users of ndo_do_ioctl are ethernet drivers that implement
the MII commands SIOCGMIIPHY/SIOCGMIIREG/SIOCSMIIREG, or hardware
timestamping with SIOCSHWTSTAMP/SIOCGHWTSTAMP.
Separate these from the few drivers that use ndo_do_ioctl to
implement SIOCBOND, SIOCBR and SIOCWANDEV commands.
This is a purely cosmetic change intended to help readers find
their way through the implementation.
Cc: Doug Ledford <dledford@redhat.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jay Vosburgh <j.vosburgh@gmail.com>
Cc: Veaceslav Falico <vfalico@gmail.com>
Cc: Andy Gospodarek <andy@greyhouse.net>
Cc: Andrew Lunn <andrew@lunn.ch>
Cc: Vivien Didelot <vivien.didelot@gmail.com>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Vladimir Oltean <olteanv@gmail.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: linux-rdma@vger.kernel.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Jason Gunthorpe <jgg@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit cc1939e4b3.
Currently 2 classes of DSA drivers are able to send/receive packets
directly through the DSA master:
- drivers with DSA_TAG_PROTO_NONE
- sja1105
Now that sja1105 has gained the ability to perform traffic termination
even under the tricky case (VLAN-aware bridge), and that is much more
functional (we can perform VLAN-aware bridging with foreign interfaces),
there is no reason to keep this code in the receive path of the network
core. So delete it.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
For a DSA switch, to offload the forwarding process of a bridge device
means to send the packets coming from the software bridge as data plane
packets. This is contrary to everything that DSA has done so far,
because the current taggers only know to send control packets (ones that
target a specific destination port), whereas data plane packets are
supposed to be forwarded according to the FDB lookup, much like packets
ingressing on any regular ingress port. If the FDB lookup process
returns multiple destination ports (flooding, multicast), then
replication is also handled by the switch hardware - the bridge only
sends a single packet and avoids the skb_clone().
DSA keeps for each bridge port a zero-based index (the number of the
bridge). Multiple ports performing TX forwarding offload to the same
bridge have the same dp->bridge_num value, and ports not offloading the
TX data plane of a bridge have dp->bridge_num = -1.
The tagger can check if the packet that is being transmitted on has
skb->offload_fwd_mark = true or not. If it does, it can be sure that the
packet belongs to the data plane of a bridge, further information about
which can be obtained based on dp->bridge_dev and dp->bridge_num.
It can then compose a DSA tag for injecting a data plane packet into
that bridge number.
For the switch driver side, we offer two new dsa_switch_ops methods,
called .port_bridge_fwd_offload_{add,del}, which are modeled after
.port_bridge_{join,leave}.
These methods are provided in case the driver needs to configure the
hardware to treat packets coming from that bridge software interface as
data plane packets. The switchdev <-> bridge interaction happens during
the netdev_master_upper_dev_link() call, so to switch drivers, the
effect is that the .port_bridge_fwd_offload_add() method is called
immediately after .port_bridge_join().
If the bridge number exceeds the number of bridges for which the switch
driver can offload the TX data plane (and this includes the case where
the driver can offload none), DSA falls back to simply returning
tx_fwd_offload = false in the switchdev_bridge_port_offload() call.
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>
In preparation of supporting data plane forwarding on behalf of a
software bridge, some drivers might need to view bridges as virtual
switches behind the CPU port in a cross-chip topology.
Give them some help and let them know how many physical switches there
are in the tree, so that they can count the virtual switches starting
from that number on.
Note that the first dsa_switch_ops method where this information is
reliably available is .setup(). This is because of how DSA works:
in a tree with 3 switches, each calling dsa_register_switch(), the first
2 will advance until dsa_tree_setup() -> dsa_tree_setup_routing_table()
and exit with error code 0 because the topology is not complete. Since
probing is parallel at this point, one switch does not know about the
existence of the other. Then the third switch comes, and for it,
dsa_tree_setup_routing_table() returns complete = true. This switch goes
ahead and calls dsa_tree_setup_switches() for everybody else, calling
their .setup() methods too. This acts as the synchronization point.
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>
Make tag_8021q a more central element of DSA and move the 2 driver
specific operations outside of struct dsa_8021q_context (which is
supposed to hold dynamic data and not really constant function
pointers).
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The basic problem description is as follows:
Be there 3 switches in a daisy chain topology:
|
sw0p0 sw0p1 sw0p2 sw0p3 sw0p4
[ user ] [ user ] [ user ] [ dsa ] [ cpu ]
|
+---------+
|
sw1p0 sw1p1 sw1p2 sw1p3 sw1p4
[ user ] [ user ] [ user ] [ dsa ] [ dsa ]
|
+---------+
|
sw2p0 sw2p1 sw2p2 sw2p3 sw2p4
[ user ] [ user ] [ user ] [ user ] [ dsa ]
The CPU will not be able to ping through the user ports of the
bottom-most switch (like for example sw2p0), simply because tag_8021q
was not coded up for this scenario - it has always assumed DSA switch
trees with a single switch.
To add support for the topology above, we must admit that the RX VLAN of
sw2p0 must be added on some ports of switches 0 and 1 as well. This is
in fact a textbook example of thing that can use the cross-chip notifier
framework that DSA has set up in switch.c.
There is only one problem: core DSA (switch.c) is not able right now to
make the connection between a struct dsa_switch *ds and a struct
dsa_8021q_context *ctx. Right now, it is drivers who call into
tag_8021q.c and always provide a struct dsa_8021q_context *ctx pointer,
and tag_8021q.c calls them back with the .tag_8021q_vlan_{add,del}
methods.
But with cross-chip notifiers, it is possible for tag_8021q to call
drivers without drivers having ever asked for anything. A good example
is right above: when sw2p0 wants to set itself up for tag_8021q,
the .tag_8021q_vlan_add method needs to be called for switches 1 and 0,
so that they transport sw2p0's VLANs towards the CPU without dropping
them.
So instead of letting drivers manage the tag_8021q context, add a
tag_8021q_ctx pointer inside of struct dsa_switch, which will be
populated when dsa_tag_8021q_register() returns success.
The patch is fairly long-winded because we are partly reverting commit
5899ee367a ("net: dsa: tag_8021q: add a context structure") which made
the driver-facing tag_8021q API use "ctx" instead of "ds". Now that we
can access "ctx" directly from "ds", this is no longer needed.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The same concerns expressed for host MDB entries are valid for host FDBs
just as well:
- in the case of multiple bridges spanning the same switch chip, deleting
a host FDB entry that belongs to one bridge will result in breakage to
the other bridge
- not deleting FDB entries across DSA links means that the switch's
hardware tables will eventually run out, given enough wear&tear
So do the same thing and introduce reference counting for CPU ports and
DSA links using the same data structures as we have for MDB entries.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Ever since the cross-chip notifiers were introduced, the design was
meant to be simplistic and just get the job done without worrying too
much about dangling resources left behind.
For example, somebody installs an MDB entry on sw0p0 in this daisy chain
topology. It gets installed using ds->ops->port_mdb_add() on sw0p0,
sw1p4 and sw2p4.
|
sw0p0 sw0p1 sw0p2 sw0p3 sw0p4
[ user ] [ user ] [ user ] [ dsa ] [ cpu ]
[ x ] [ ] [ ] [ ] [ ]
|
+---------+
|
sw1p0 sw1p1 sw1p2 sw1p3 sw1p4
[ user ] [ user ] [ user ] [ dsa ] [ dsa ]
[ ] [ ] [ ] [ ] [ x ]
|
+---------+
|
sw2p0 sw2p1 sw2p2 sw2p3 sw2p4
[ user ] [ user ] [ user ] [ user ] [ dsa ]
[ ] [ ] [ ] [ ] [ x ]
Then the same person deletes that MDB entry. The cross-chip notifier for
deletion only matches sw0p0:
|
sw0p0 sw0p1 sw0p2 sw0p3 sw0p4
[ user ] [ user ] [ user ] [ dsa ] [ cpu ]
[ x ] [ ] [ ] [ ] [ ]
|
+---------+
|
sw1p0 sw1p1 sw1p2 sw1p3 sw1p4
[ user ] [ user ] [ user ] [ dsa ] [ dsa ]
[ ] [ ] [ ] [ ] [ ]
|
+---------+
|
sw2p0 sw2p1 sw2p2 sw2p3 sw2p4
[ user ] [ user ] [ user ] [ user ] [ dsa ]
[ ] [ ] [ ] [ ] [ ]
Why?
Because the DSA links are 'trunk' ports, if we just go ahead and delete
the MDB from sw1p4 and sw2p4 directly, we might delete those multicast
entries when they are still needed. Just consider the fact that somebody
does:
- add a multicast MAC address towards sw0p0 [ via the cross-chip
notifiers it gets installed on the DSA links too ]
- add the same multicast MAC address towards sw0p1 (another port of that
same switch)
- delete the same multicast MAC address from sw0p0.
At this point, if we deleted the MAC address from the DSA links, it
would be flooded, even though there is still an entry on switch 0 which
needs it not to.
So that is why deletions only match the targeted source port and nothing
on DSA links. Of course, dangling resources means that the hardware
tables will eventually run out given enough additions/removals, but hey,
at least it's simple.
But there is a bigger concern which needs to be addressed, and that is
our support for SWITCHDEV_OBJ_ID_HOST_MDB. DSA simply translates such an
object into a dsa_port_host_mdb_add() which ends up as ds->ops->port_mdb_add()
on the upstream port, and a similar thing happens on deletion:
dsa_port_host_mdb_del() will trigger ds->ops->port_mdb_del() on the
upstream port.
When there are 2 VLAN-unaware bridges spanning the same switch (which is
a use case DSA proudly supports), each bridge will install its own
SWITCHDEV_OBJ_ID_HOST_MDB entries. But upon deletion, DSA goes ahead and
emits a DSA_NOTIFIER_MDB_DEL for dp->cpu_dp, which is shared between the
user ports enslaved to br0 and the user ports enslaved to br1. Not good.
The host-trapped multicast addresses installed by br1 will be deleted
when any state changes in br0 (IGMP timers expire, or ports leave, etc).
To avoid this, we could of course go the route of the zero-sum game and
delete the DSA_NOTIFIER_MDB_DEL call for dp->cpu_dp. But the better
design is to just admit that on shared ports like DSA links and CPU
ports, we should be reference counting calls, even if this consumes some
dynamic memory which DSA has traditionally avoided. On the flip side,
the hardware tables of switches are limited in size, so it would be good
if the OS managed them properly instead of having them eventually
overflow.
To address the memory usage concern, we only apply the refcounting of
MDB entries on ports that are really shared (CPU ports and DSA links)
and not on user ports. In a typical single-switch setup, this means only
the CPU port (and the host MDB entries are not that many, really).
The name of the newly introduced data structures (dsa_mac_addr) is
chosen in such a way that will be reusable for host FDB entries (next
patch).
With this change, we can finally have the same matching logic for the
MDB additions and deletions, as well as for their host-trapped variants.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
In preparation for the new cross-chip notifiers for host addresses,
let's introduce some more topology helpers which we are going to use to
discern switches that are in our path towards the dedicated CPU port
from switches that aren't.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Luiz Angelo Daros de Luca