After the blamed commit, dsa_tree_setup_master() may exit without
calling rtnl_unlock(), fix that.
Fixes: c146f9bc19 ("net: dsa: hold rtnl_mutex when calling dsa_master_{setup,teardown}")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The blamed commit said one thing but did another. It explains that we
should restore the "return err" to the original "goto out_unwind_tagger",
but instead it replaced it with "goto out_unlock".
When DSA_NOTIFIER_TAG_PROTO fails after the first switch of a
multi-switch tree, the switches would end up not using the same tagging
protocol.
Fixes: 0b0e2ff103 ("net: dsa: restore error path of dsa_tree_change_tag_proto")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220303154249.1854436-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
When the DSA_NOTIFIER_TAG_PROTO returns an error, the user space process
which initiated the protocol change exits the kernel processing while
still holding the rtnl_mutex. So any other process attempting to lock
the rtnl_mutex would deadlock after such event.
The error handling of DSA_NOTIFIER_TAG_PROTO was inadvertently changed
by the blamed commit, introducing this regression. We must still call
rtnl_unlock(), and we must still call DSA_NOTIFIER_TAG_PROTO for the old
protocol. The latter is due to the limiting design of notifier chains
for cross-chip operations, which don't have a built-in error recovery
mechanism - we should look into using notifier_call_chain_robust for that.
Fixes: dc452a471d ("net: dsa: introduce tagger-owned storage for private and shared data")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Link: https://lore.kernel.org/r/20220228141715.146485-1-vladimir.oltean@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
If a bridged port is not offloaded to the hardware - either because the
underlying driver does not implement the port_bridge_{join,leave} ops,
or because the operation failed - then its dp->bridge pointer will be
NULL when dsa_port_bridge_leave() is called. Avoid dereferncing NULL.
This fixes the following splat when removing a port from a bridge:
Unable to handle kernel access to user memory outside uaccess routines at virtual address 0000000000000000
Internal error: Oops: 96000004 [#1] PREEMPT_RT SMP
CPU: 3 PID: 1119 Comm: brctl Tainted: G O 5.17.0-rc4-rt4 #1
Call trace:
dsa_port_bridge_leave+0x8c/0x1e4
dsa_slave_changeupper+0x40/0x170
dsa_slave_netdevice_event+0x494/0x4d4
notifier_call_chain+0x80/0xe0
raw_notifier_call_chain+0x1c/0x24
call_netdevice_notifiers_info+0x5c/0xac
__netdev_upper_dev_unlink+0xa4/0x200
netdev_upper_dev_unlink+0x38/0x60
del_nbp+0x1b0/0x300
br_del_if+0x38/0x114
add_del_if+0x60/0xa0
br_ioctl_stub+0x128/0x2dc
br_ioctl_call+0x68/0xb0
dev_ifsioc+0x390/0x554
dev_ioctl+0x128/0x400
sock_do_ioctl+0xb4/0xf4
sock_ioctl+0x12c/0x4e0
__arm64_sys_ioctl+0xa8/0xf0
invoke_syscall+0x4c/0x110
el0_svc_common.constprop.0+0x48/0xf0
do_el0_svc+0x28/0x84
el0_svc+0x1c/0x50
el0t_64_sync_handler+0xa8/0xb0
el0t_64_sync+0x17c/0x180
Code: f9402f00 f0002261 f9401302 913cc021 (a9401404)
---[ end trace 0000000000000000 ]---
Fixes: d3eed0e57d ("net: dsa: keep the bridge_dev and bridge_num as part of the same structure")
Signed-off-by: Alvin Šipraga <alsi@bang-olufsen.dk>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220221203539.310690-1-alvin@pqrs.dk
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
If the DSA master doesn't support IFF_UNICAST_FLT, then the following
call path is possible:
dsa_slave_switchdev_event_work
-> dsa_port_host_fdb_add
-> dev_uc_add
-> __dev_set_rx_mode
-> __dev_set_promiscuity
Since the blamed commit, dsa_slave_switchdev_event_work() no longer
holds rtnl_lock(), which triggers the ASSERT_RTNL() from
__dev_set_promiscuity().
Taking rtnl_lock() around dev_uc_add() is impossible, because all the
code paths that call dsa_flush_workqueue() do so from contexts where the
rtnl_mutex is already held - so this would lead to an instant deadlock.
dev_uc_add() in itself doesn't require the rtnl_mutex for protection.
There is this comment in __dev_set_rx_mode() which assumes so:
/* Unicast addresses changes may only happen under the rtnl,
* therefore calling __dev_set_promiscuity here is safe.
*/
but it is from commit 4417da668c ("[NET]: dev: secondary unicast
address support") dated June 2007, and in the meantime, commit
f1f28aa351 ("netdev: Add addr_list_lock to struct net_device."), dated
July 2008, has added &dev->addr_list_lock to protect this instead of the
global rtnl_mutex.
Nonetheless, __dev_set_promiscuity() does assume rtnl_mutex protection,
but it is the uncommon path of what we typically expect dev_uc_add()
to do. So since only the uncommon path requires rtnl_lock(), just check
ahead of time whether dev_uc_add() would result into a call to
__dev_set_promiscuity(), and handle that condition separately.
DSA already configures the master interface to be promiscuous if the
tagger requires this. We can extend this to also cover the case where
the master doesn't handle dev_uc_add() (doesn't support IFF_UNICAST_FLT),
and on the premise that we'd end up making it promiscuous during
operation anyway, either if a DSA slave has a non-inherited MAC address,
or if the bridge notifies local FDB entries for its own MAC address, the
address of a station learned on a foreign port, etc.
Fixes: 0faf890fc5 ("net: dsa: drop rtnl_lock from dsa_slave_switchdev_event_work")
Reported-by: Oleksij Rempel <o.rempel@pengutronix.de>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Check for a hwaccel VLAN tag on rx and use it if present. Otherwise,
use __skb_vlan_pop() like the other tag parsers do. This fixes the case
where the VLAN tag has already been consumed by the master.
Fixes: a1292595e0 ("net: dsa: add new DSA switch driver for the SMSC-LAN9303")
Signed-off-by: Mans Rullgard <mans@mansr.com>
Reviewed-by: Vladimir Oltean <olteanv@gmail.com>
Link: https://lore.kernel.org/r/20220216124634.23123-1-mans@mansr.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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 c9eb3e0f87 ("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: c9eb3e0f87 ("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>
Rafael reports that on a system with LX2160A and Marvell DSA switches,
if a reboot occurs while the DSA master (dpaa2-eth) is up, the following
panic can be seen:
systemd-shutdown[1]: Rebooting.
Unable to handle kernel paging request at virtual address 00a0000800000041
[00a0000800000041] address between user and kernel address ranges
Internal error: Oops: 96000004 [#1] PREEMPT SMP
CPU: 6 PID: 1 Comm: systemd-shutdow Not tainted 5.16.5-00042-g8f5585009b24 #32
pc : dsa_slave_netdevice_event+0x130/0x3e4
lr : raw_notifier_call_chain+0x50/0x6c
Call trace:
dsa_slave_netdevice_event+0x130/0x3e4
raw_notifier_call_chain+0x50/0x6c
call_netdevice_notifiers_info+0x54/0xa0
__dev_close_many+0x50/0x130
dev_close_many+0x84/0x120
unregister_netdevice_many+0x130/0x710
unregister_netdevice_queue+0x8c/0xd0
unregister_netdev+0x20/0x30
dpaa2_eth_remove+0x68/0x190
fsl_mc_driver_remove+0x20/0x5c
__device_release_driver+0x21c/0x220
device_release_driver_internal+0xac/0xb0
device_links_unbind_consumers+0xd4/0x100
__device_release_driver+0x94/0x220
device_release_driver+0x28/0x40
bus_remove_device+0x118/0x124
device_del+0x174/0x420
fsl_mc_device_remove+0x24/0x40
__fsl_mc_device_remove+0xc/0x20
device_for_each_child+0x58/0xa0
dprc_remove+0x90/0xb0
fsl_mc_driver_remove+0x20/0x5c
__device_release_driver+0x21c/0x220
device_release_driver+0x28/0x40
bus_remove_device+0x118/0x124
device_del+0x174/0x420
fsl_mc_bus_remove+0x80/0x100
fsl_mc_bus_shutdown+0xc/0x1c
platform_shutdown+0x20/0x30
device_shutdown+0x154/0x330
__do_sys_reboot+0x1cc/0x250
__arm64_sys_reboot+0x20/0x30
invoke_syscall.constprop.0+0x4c/0xe0
do_el0_svc+0x4c/0x150
el0_svc+0x24/0xb0
el0t_64_sync_handler+0xa8/0xb0
el0t_64_sync+0x178/0x17c
It can be seen from the stack trace that the problem is that the
deregistration of the master causes a dev_close(), which gets notified
as NETDEV_GOING_DOWN to dsa_slave_netdevice_event().
But dsa_switch_shutdown() has already run, and this has unregistered the
DSA slave interfaces, and yet, the NETDEV_GOING_DOWN handler attempts to
call dev_close_many() on those slave interfaces, leading to the problem.
The previous attempt to avoid the NETDEV_GOING_DOWN on the master after
dsa_switch_shutdown() was called seems improper. Unregistering the slave
interfaces is unnecessary and unhelpful. Instead, after the slaves have
stopped being uppers of the DSA master, we can now reset to NULL the
master->dsa_ptr pointer, which will make DSA start ignoring all future
notifier events on the master.
Fixes: 0650bf52b3 ("net: dsa: be compatible with masters which unregister on shutdown")
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>
It is said that as soon as a network interface is registered, all its
resources should have already been prepared, so that it is available for
sending and receiving traffic. One of the resources needed by a DSA
slave interface is the master.
dsa_tree_setup
-> dsa_tree_setup_ports
-> dsa_port_setup
-> dsa_slave_create
-> register_netdevice
-> dsa_tree_setup_master
-> dsa_master_setup
-> sets up master->dsa_ptr, which enables reception
Therefore, there is a short period of time after register_netdevice()
during which the master isn't prepared to pass traffic to the DSA layer
(master->dsa_ptr is checked by eth_type_trans). Same thing during
unregistration, there is a time frame in which packets might be missed.
Note that this change opens us to another race: dsa_master_find_slave()
will get invoked potentially earlier than the slave creation, and later
than the slave deletion. Since dp->slave starts off as a NULL pointer,
the earlier calls aren't a problem, but the later calls are. To avoid
use-after-free, we should zeroize dp->slave before calling
dsa_slave_destroy().
In practice I cannot really test real life improvements brought by this
change, since in my systems, netdevice creation races with PHY autoneg
which takes a few seconds to complete, and that masks quite a few races.
Effects might be noticeable in a setup with fixed links all the way to
an external system.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After commit a57d8c217a ("net: dsa: flush switchdev workqueue before
tearing down CPU/DSA ports"), the port setup and teardown procedure
became asymmetric.
The fact of the matter is that user ports need the shared ports to be up
before they can be used for CPU-initiated termination. And since we
register net devices for the user ports, those won't be functional until
we also call the setup for the shared (CPU, DSA) ports. But we may do
that later, depending on the port numbering scheme of the hardware we
are dealing with.
It just makes sense that all shared ports are brought up before any user
port is. I can't pinpoint any issue due to the current behavior, but
let's change it nonetheless, for consistency's sake.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
DSA needs to simulate master tracking events when a binding is first
with a DSA master established and torn down, in order to give drivers
the simplifying guarantee that ->master_state_change calls are made
only when the master's readiness state to pass traffic changes.
master_state_change() provide a operational bool that DSA driver can use
to understand if DSA master is operational or not.
To avoid races, we need to block the reception of
NETDEV_UP/NETDEV_CHANGE/NETDEV_GOING_DOWN events in the netdev notifier
chain while we are changing the master's dev->dsa_ptr (this changes what
netdev_uses_dsa(dev) reports).
The dsa_master_setup() and dsa_master_teardown() functions optionally
require the rtnl_mutex to be held, if the tagger needs the master to be
promiscuous, these functions call dev_set_promiscuity(). Move the
rtnl_lock() from that function and make it top-level.
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>
At present there are two paths for changing the MTU of the DSA master.
The first is:
dsa_tree_setup
-> dsa_tree_setup_ports
-> dsa_port_setup
-> dsa_slave_create
-> dsa_slave_change_mtu
-> dev_set_mtu(master)
The second is:
dsa_tree_setup
-> dsa_tree_setup_master
-> dsa_master_setup
-> dev_set_mtu(dev)
So the dev_set_mtu() call from dsa_master_setup() has been effectively
superseded by the dsa_slave_change_mtu(slave_dev, ETH_DATA_LEN) that is
done from dsa_slave_create() for each user port. The later function also
updates the master MTU according to the largest user port MTU from the
tree. Therefore, updating the master MTU through a separate code path
isn't needed.
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>
Currently dsa_slave_create() has two sequences of rtnl_lock/rtnl_unlock
in a row. Remove the rtnl_unlock() and rtnl_lock() in between, such that
the operation can execute slighly faster.
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 dsa_slave_create() there are 2 sections that take rtnl_lock():
MTU change and netdev registration. They are separated by PHY
initialization.
There isn't any strict ordering requirement except for the fact that
netdev registration should be last. Therefore, we can perform the MTU
change a bit later, after the PHY setup. A future change will then be
able to merge the two rtnl_lock sections into one.
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>
The cross-chip notifiers for HSR are bypass operations, meaning that
even though all switches in a tree are notified, only the switch
specified in the info structure is targeted.
We can eliminate the unnecessary complexity by deleting the cross-chip
notifier logic and calling the ds->ops straight from port.c.
Cc: George McCollister <george.mccollister@gmail.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: George McCollister <george.mccollister@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The cross-chip notifiers for MRP are bypass operations, meaning that
even though all switches in a tree are notified, only the switch
specified in the info structure is targeted.
We can eliminate the unnecessary complexity by deleting the cross-chip
notifier logic and calling the ds->ops straight from port.c.
Cc: Horatiu Vultur <horatiu.vultur@microchip.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The cross-chip notifier boilerplate code meant to check the presence of
ds->ops->port_mrp_add_ring_role before calling it, but checked
ds->ops->port_mrp_add instead, before calling
ds->ops->port_mrp_add_ring_role.
Therefore, a driver which implements one operation but not the other
would trigger a NULL pointer dereference.
There isn't any such driver in DSA yet, so there is no reason to
backport the change. Issue found through code inspection.
Cc: Horatiu Vultur <horatiu.vultur@microchip.com>
Fixes: c595c4330d ("net: dsa: add MRP support")
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Alexei Starovoitov says:
====================
pull-request: bpf-next 2021-12-30
The following pull-request contains BPF updates for your *net-next* tree.
We've added 72 non-merge commits during the last 20 day(s) which contain
a total of 223 files changed, 3510 insertions(+), 1591 deletions(-).
The main changes are:
1) Automatic setrlimit in libbpf when bpf is memcg's in the kernel, from Andrii.
2) Beautify and de-verbose verifier logs, from Christy.
3) Composable verifier types, from Hao.
4) bpf_strncmp helper, from Hou.
5) bpf.h header dependency cleanup, from Jakub.
6) get_func_[arg|ret|arg_cnt] helpers, from Jiri.
7) Sleepable local storage, from KP.
8) Extend kfunc with PTR_TO_CTX, PTR_TO_MEM argument support, from Kumar.
====================
Signed-off-by: David S. Miller <davem@davemloft.net>
sock.h is pretty heavily used (5k objects rebuilt on x86 after
it's touched). We can drop the include of filter.h from it and
add a forward declaration of struct sk_filter instead.
This decreases the number of rebuilt objects when bpf.h
is touched from ~5k to ~1k.
There's a lot of missing includes this was masking. Primarily
in networking tho, this time.
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: Marc Kleine-Budde <mkl@pengutronix.de>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Acked-by: Nikolay Aleksandrov <nikolay@nvidia.com>
Acked-by: Stefano Garzarella <sgarzare@redhat.com>
Link: https://lore.kernel.org/bpf/20211229004913.513372-1-kuba@kernel.org
For Ocelot switches, the CPU injected frames have an injection header
where it can specify the QoS class of the packet and the DSA tag, now it
uses the SKB priority to set that. If a traffic class to priority
mapping is configured on the netdevice (with mqprio for example ...), it
won't be considered for CPU injected headers. This patch make the QoS
class aligned to the priority to traffic class mapping if it exists.
Fixes: 8dce89aa5f ("net: dsa: ocelot: add tagger for Ocelot/Felix switches")
Signed-off-by: Xiaoliang Yang <xiaoliang.yang_1@nxp.com>
Signed-off-by: Marouen Ghodhbane <marouen.ghodhbane@nxp.com>
Link: https://lore.kernel.org/r/20211223072211.33130-1-xiaoliang.yang_1@nxp.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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>
The method was meant to zeroize ds->tagger_data but got the wrong
pointer. Fix this.
Fixes: c79e84866d ("net: dsa: tag_sja1105: convert to tagger-owned data")
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>
The sja1105 driver messes with the tagging protocol's state when PTP RX
timestamping is enabled/disabled. This is fundamentally necessary
because the tagger needs to know what to do when it receives a PTP
packet. If RX timestamping is enabled, then a metadata follow-up frame
is expected, and this holds the (partial) timestamp. So the tagger plays
hide-and-seek with the network stack until it also gets the metadata
frame, and then presents a single packet, the timestamped PTP packet.
But when RX timestamping isn't enabled, there is no metadata frame
expected, so the hide-and-seek game must be turned off and the packet
must be delivered right away to the network stack.
Considering this, we create a pseudo isolation by devising two tagger
methods callable by the switch: one to get the RX timestamping state,
and one to set it. Since we can't export symbols between the tagger and
the switch driver, these methods are exposed through function pointers.
After this change, the public portion of the sja1105_tagger_data
contains only function pointers.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This reverts commit 6d709cadfd.
The above change was done to avoid calling symbols exported by the
switch driver from the tagging protocol driver.
With the tagger-owned storage model, we have a new option on our hands,
and that is for the switch driver to provide a data consumer handler in
the form of a function pointer inside the ->connect_tag_protocol()
method. Having a function pointer avoids the problems of the exported
symbols approach.
By creating a handler for metadata frames holding TX timestamps on
SJA1110, we are able to eliminate an skb queue from the tagger data, and
replace it with a simple, and stateless, function pointer. This skb
queue is now handled exclusively by sja1105_ptp.c, which makes the code
easier to follow, as it used to be before the reverted patch.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Currently, struct sja1105_tagger_data is a part of struct
sja1105_private, and is used by the sja1105 driver to populate dp->priv.
With the movement towards tagger-owned storage, the sja1105 driver
should not be the owner of this memory.
This change implements the connection between the sja1105 switch driver
and its tagging protocol, which means that sja1105_tagger_data no longer
stays in dp->priv but in ds->tagger_data, and that the sja1105 driver
now only populates the sja1105_port_deferred_xmit callback pointer.
The kthread worker is now the responsibility of the tagger.
The sja1105 driver also alters the tagger's state some more, especially
with regard to the PTP RX timestamping state. This will be fixed up a
bit in further changes.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The design of the sja1105 tagger dp->priv is that each port has a
separate struct sja1105_port, and the sp->data pointer points to a
common struct sja1105_tagger_data.
We have removed all per-port members accessible by the tagger, and now
only struct sja1105_tagger_data remains. Make dp->priv point directly to
this.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
When the ocelot-8021q driver was converted to deferred xmit as part of
commit 8d5f7954b7 ("net: dsa: felix: break at first CPU port during
init and teardown"), the deferred implementation was deliberately made
subtly different from what sja1105 has.
The implementation differences lied on the following observations:
- There might be a race between these two lines in tag_sja1105.c:
skb_queue_tail(&sp->xmit_queue, skb_get(skb));
kthread_queue_work(sp->xmit_worker, &sp->xmit_work);
and the skb dequeue logic in sja1105_port_deferred_xmit(). For
example, the xmit_work might be already queued, however the work item
has just finished walking through the skb queue. Because we don't
check the return code from kthread_queue_work, we don't do anything if
the work item is already queued.
However, nobody will take that skb and send it, at least until the
next timestampable skb is sent. This creates additional (and
avoidable) TX timestamping latency.
To close that race, what the ocelot-8021q driver does is it doesn't
keep a single work item per port, and a skb timestamping queue, but
rather dynamically allocates a work item per packet.
- It is also unnecessary to have more than one kthread that does the
work. So delete the per-port kthread allocations and replace them with
a single kthread which is global to the switch.
This change brings the two implementations in line by applying those
observations to the sja1105 driver as well.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
The felix driver makes very light use of dp->priv, and the tagger is
effectively stateless. dp->priv is practically only needed to set up a
callback to perform deferred xmit of PTP and STP packets using the
ocelot-8021q tagging protocol (the main ocelot tagging protocol makes no
use of dp->priv, although this driver sets up dp->priv irrespective of
actual tagging protocol in use).
struct felix_port (what used to be pointed to by dp->priv) is removed
and replaced with a two-sided structure. The public side of this
structure, visible to the switch driver, is ocelot_8021q_tagger_data.
The private side is ocelot_8021q_tagger_private, and the latter
structure physically encapsulates the former. The public half of the
tagger data structure can be accessed through a helper of the same name
(ocelot_8021q_tagger_data) which also sanity-checks the protocol
currently in use by the switch. The public/private split was requested
by Andrew Lunn.
Suggested-by: Andrew Lunn <andrew@lunn.ch>
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>
The majority of DSA drivers do not make use of the PCS support, and
thus operate in legacy mode. In order to preserve this behaviour in
future, we need to set the legacy_pre_march2020 flag so phylink knows
this may require the legacy calls.
There are some DSA drivers that do make use of PCS support, and these
will continue operating as before - legacy_pre_march2020 will not
prevent split-PCS support enabling the newer phylink behaviour.
Signed-off-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
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>
Currently the majority of dsa_port_bridge_dev_get() calls in drivers is
just to check whether a port is under the bridge device provided as
argument by the DSA API.
We'd like to change that DSA API so that a more complex structure is
provided as argument. To keep things more generic, and considering that
the new complex structure will be provided by value and not by
reference, direct comparisons between dp->bridge and the provided bridge
will be broken. The generic way to do the checking would simply be to
do something like dsa_port_offloads_bridge(dp, &bridge).
But there's a problem, we already have a function named that way, which
actually takes a bridge_dev net_device as argument. Rename it so that we
can use dsa_port_offloads_bridge for something else.
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>
Support the use of phylink_generic_validate() when there is no
phylink_validate method given in the DSA switch operations and
mac_capabilities have been set in the phylink_config structure by the
DSA switch driver.
This gives DSA switch drivers the option to use this if they provide
the supported_interfaces and mac_capabilities, while still giving them
an option to override the default implementation if necessary.
Reviewed-by: Vladimir Oltean <vladimir.oltean@nxp.com>
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>
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>
The code in port.c and slave.c creating the phylink instance is very
similar - let's consolidate this into a single function.
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>
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>
Normally it is expected that the dsa_device_ops :: rcv() method finishes
parsing the DSA tag and consumes it, then never looks at it again.
But commit c0bcf53766 ("net: dsa: ocelot: add hardware timestamping
support for Felix") added support for RX timestamping in a very
unconventional way. On this switch, a partial timestamp is available in
the DSA header, but the driver got away with not parsing that timestamp
right away, but instead delayed that parsing for a little longer:
dsa_switch_rcv():
nskb = cpu_dp->rcv(skb, dev); <------------- not here
-> ocelot_rcv()
...
skb = nskb;
skb_push(skb, ETH_HLEN);
skb->pkt_type = PACKET_HOST;
skb->protocol = eth_type_trans(skb, skb->dev);
...
if (dsa_skb_defer_rx_timestamp(p, skb)) <--- but here
-> felix_rxtstamp()
return 0;
When in felix_rxtstamp(), this driver accounted for the fact that
eth_type_trans() happened in the meanwhile, so it got a hold of the
extraction header again by subtracting (ETH_HLEN + OCELOT_TAG_LEN) bytes
from the current skb->data.
This worked for quite some time but was quite fragile from the very
beginning. Not to mention that having DSA tag parsing split in two
different files, under different folders (net/dsa/tag_ocelot.c vs
drivers/net/dsa/ocelot/felix.c) made it quite non-obvious for patches to
come that they might break this.
Finally, the blamed commit does the following: at the end of
ocelot_rcv(), it checks whether the skb payload contains a VLAN header.
If it does, and this port is under a VLAN-aware bridge, that VLAN ID
might not be correct in the sense that the packet might have suffered
VLAN rewriting due to TCAM rules (VCAP IS1). So we consume the VLAN ID
from the skb payload using __skb_vlan_pop(), and take the classified
VLAN ID from the DSA tag, and construct a hwaccel VLAN tag with the
classified VLAN, and the skb payload is VLAN-untagged.
The big problem is that __skb_vlan_pop() does:
memmove(skb->data + VLAN_HLEN, skb->data, 2 * ETH_ALEN);
__skb_pull(skb, VLAN_HLEN);
aka it moves the Ethernet header 4 bytes to the right, and pulls 4 bytes
from the skb headroom (effectively also moving skb->data, by definition).
So for felix_rxtstamp()'s fragile logic, all bets are off now.
Instead of having the "extraction" pointer point to the DSA header,
it actually points to 4 bytes _inside_ the extraction header.
Corollary, the last 4 bytes of the "extraction" header are in fact 4
stale bytes of the destination MAC address from the Ethernet header,
from prior to the __skb_vlan_pop() movement.
So of course, RX timestamps are completely bogus when the system is
configured in this way.
The fix is actually very simple: just don't structure the code like that.
For better or worse, the DSA PTP timestamping API does not offer a
straightforward way for drivers to present their RX timestamps, but
other drivers (sja1105) have established a simple mechanism to carry
their RX timestamp from dsa_device_ops :: rcv() all the way to
dsa_switch_ops :: port_rxtstamp() and even later. That mechanism is to
simply save the partial timestamp to the skb->cb, and complete it later.
Question: why don't we simply populate the skb's struct
skb_shared_hwtstamps from ocelot_rcv(), and bother with this
complication of propagating the timestamp to felix_rxtstamp()?
Answer: dsa_switch_ops :: port_rxtstamp() answers the question whether
PTP packets need sleepable context to retrieve the full RX timestamp.
Currently felix_rxtstamp() answers "no, thanks" to that question, and
calls ocelot_ptp_gettime64() from softirq atomic context. This is
understandable, since Felix VSC9959 is a PCIe memory-mapped switch, so
hardware access does not require sleeping. But the felix driver is
preparing for the introduction of other switches where hardware access
is over a slow bus like SPI or MDIO:
https://lore.kernel.org/lkml/20210814025003.2449143-1-colin.foster@in-advantage.com/
So I would like to keep this code structure, so the rework needed when
that driver will need PTP support will be minimal (answer "yes, I need
deferred context for this skb's RX timestamp", then the partial
timestamp will still be found in the skb->cb.
Fixes: ea440cd2d9 ("net: dsa: tag_ocelot: use VLAN information from tagging header when available")
Reported-by: Po Liu <po.liu@nxp.com>
Cc: Yangbo Lu <yangbo.lu@nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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>
To reduce code churn, the same patch makes multiple changes, since they
all touch the same lines:
1. The implementations for these two are identical, just with different
function pointers. Reduce duplications and name the function pointers
"mod_cb" instead of "add_cb" and "del_cb". Pass the event as argument.
2. Drop the "const" attribute from "orig_dev". If the driver needs to
check whether orig_dev belongs to itself and then
call_switchdev_notifiers(orig_dev, SWITCHDEV_FDB_OFFLOADED), it
can't, because call_switchdev_notifiers takes a non-const struct
net_device *.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Now that we guarantee that SWITCHDEV_FDB_{ADD,DEL}_TO_DEVICE events have
finished executing by the time we leave our bridge upper interface,
we've established a stronger boundary condition for how long the
dsa_slave_switchdev_event_work() might run.
As such, it is no longer possible for DSA slave interfaces to become
unregistered, since they are still bridge ports.
So delete the unnecessary dev_hold() and dev_put().
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
DSA is preparing to offer switch drivers an API through which they can
associate each FDB entry with a struct net_device *bridge_dev. This can
be used to perform FDB isolation (the FDB lookup performed on the
ingress of a standalone, or bridged port, should not find an FDB entry
that is present in the FDB of another bridge).
In preparation of that work, DSA needs to ensure that by the time we
call the switch .port_fdb_add and .port_fdb_del methods, the
dp->bridge_dev pointer is still valid, i.e. the port is still a bridge
port.
This is not guaranteed because the SWITCHDEV_FDB_{ADD,DEL}_TO_DEVICE API
requires drivers that must have sleepable context to handle those events
to schedule the deferred work themselves. DSA does this through the
dsa_owq.
It can happen that a port leaves a bridge, del_nbp() flushes the FDB on
that port, SWITCHDEV_FDB_DEL_TO_DEVICE is notified in atomic context,
DSA schedules its deferred work, but del_nbp() finishes unlinking the
bridge as a master from the port before DSA's deferred work is run.
Fundamentally, the port must not be unlinked from the bridge until all
FDB deletion deferred work items have been flushed. The bridge must wait
for the completion of these hardware accesses.
An attempt has been made to address this issue centrally in switchdev by
making SWITCHDEV_FDB_DEL_TO_DEVICE deferred (=> blocking) at the switchdev
level, which would offer implicit synchronization with del_nbp:
https://patchwork.kernel.org/project/netdevbpf/cover/20210820115746.3701811-1-vladimir.oltean@nxp.com/
but it seems that any attempt to modify switchdev's behavior and make
the events blocking there would introduce undesirable side effects in
other switchdev consumers.
The most undesirable behavior seems to be that
switchdev_deferred_process_work() takes the rtnl_mutex itself, which
would be worse off than having the rtnl_mutex taken individually from
drivers which is what we have now (except DSA which has removed that
lock since commit 0faf890fc5 ("net: dsa: drop rtnl_lock from
dsa_slave_switchdev_event_work")).
So to offer the needed guarantee to DSA switch drivers, I have come up
with a compromise solution that does not require switchdev rework:
we already have a hook at the last moment in time when the bridge is
still an upper of ours: the NETDEV_PRECHANGEUPPER handler. We can flush
the dsa_owq manually from there, which makes all FDB deletions
synchronous.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
After talking with Ido Schimmel, it became clear that rtnl_lock is not
actually required for anything that is done inside the
SWITCHDEV_FDB_{ADD,DEL}_TO_DEVICE deferred work handlers.
The reason why it was probably added by Arkadi Sharshevsky in commit
c9eb3e0f87 ("net: dsa: Add support for learning FDB through
notification") was to offer the same locking/serialization guarantees as
.ndo_fdb_{add,del} and avoid reworking any drivers.
DSA has implemented .ndo_fdb_add and .ndo_fdb_del until commit
b117e1e8a8 ("net: dsa: delete dsa_legacy_fdb_add and
dsa_legacy_fdb_del") - that is to say, until fairly recently.
But those methods have been deleted, so now we are free to drop the
rtnl_lock as well.
Note that exposing DSA switch drivers to an unlocked method which was
previously serialized by the rtnl_mutex is a potentially dangerous
affair. Driver writers couldn't ensure that their internal locking
scheme does the right thing even if they wanted.
We could err on the side of paranoia and introduce a switch-wide lock
inside the DSA framework, but that seems way overreaching. Instead, we
could check as many drivers for regressions as we can, fix those first,
then let this change go in once it is assumed to be fairly safe.
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>
