kernel.git/net/dsa/dsa2.c, branch linux-5.17.y

Revert "net: dsa: setup master before ports"

2022-04-20T07:36:27Z

commit 762c2998c9625f642f0d23da7d3f7e4f90665fdf upstream. This reverts commit 11fd667dac315ea3f2469961f6d2869271a46cae. dsa_slave_change_mtu() updates the MTU of the DSA master and of the associated CPU port, but only if it detects a change to the master MTU. The blamed commit in the Fixes: tag below addressed a regression where dsa_slave_change_mtu() would return early and not do anything due to ds->ops->port_change_mtu() not being implemented. However, that commit also had the effect that the master MTU got set up to the correct value by dsa_master_setup(), but the associated CPU port's MTU did not get updated. This causes breakage for drivers that rely on the ->port_change_mtu() DSA call to account for the tagging overhead on the CPU port, and don't set up the initial MTU during the setup phase. Things actually worked before because they were in a fragile equilibrium where dsa_slave_change_mtu() was called before dsa_master_setup() was. So dsa_slave_change_mtu() could actually detect a change and update the CPU port MTU too. Restore the code to the way things used to work by reverting the reorder of dsa_tree_setup_master() and dsa_tree_setup_ports(). That change did not have a concrete motivation going for it anyway, it just looked better. Fixes: 066dfc429040 ("Revert "net: dsa: stop updating master MTU from master.c"") Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller Signed-off-by: Greg Kroah-Hartman

net: dsa: fix panic on shutdown if multi-chip tree failed to probe

2022-04-08T11:58:22Z

[ Upstream commit 8fd36358ce82382519b50b05f437493e1e00c4a9 ] DSA probing is atypical because a tree of devices must probe all at once, so out of N switches which call dsa_tree_setup_routing_table() during probe, for (N - 1) of them, "complete" will return false and they will exit probing early. The Nth switch will set up the whole tree on their behalf. The implication is that for (N - 1) switches, the driver binds to the device successfully, without doing anything. When the driver is bound, the ->shutdown() method may run. But if the Nth switch has failed to initialize the tree, there is nothing to do for the (N - 1) driver instances, since the slave devices have not been created, etc. Moreover, dsa_switch_shutdown() expects that the calling @ds has been in fact initialized, so it jumps at dereferencing the various data structures, which is incorrect. Avoid the ensuing NULL pointer dereferences by simply checking whether the Nth switch has previously set "ds->setup = true" for the switch which is currently shutting down. The entire setup is serialized under dsa2_mutex which we already hold. Fixes: 0650bf52b31f ("net: dsa: be compatible with masters which unregister on shutdown") Signed-off-by: Vladimir Oltean Link: https://lore.kernel.org/r/20220318195443.275026-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin

net: dsa: Add missing of_node_put() in dsa_port_parse_of

2022-03-17T12:13:27Z

The device_node pointer is returned by of_parse_phandle() with refcount incremented. We should use of_node_put() on it when done. Fixes: 6d4e5c570c2d ("net: dsa: get port type at parse time") Signed-off-by: Miaoqian Lin Link: https://lore.kernel.org/r/20220316082602.10785-1-linmq006@gmail.com Signed-off-by: Paolo Abeni

net: dsa: unlock the rtnl_mutex when dsa_master_setup() fails

2022-03-06T10:55:54Z

After the blamed commit, dsa_tree_setup_master() may exit without calling rtnl_unlock(), fix that. Fixes: c146f9bc195a ("net: dsa: hold rtnl_mutex when calling dsa_master_{setup,teardown}") Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller

net: dsa: make dsa_tree_change_tag_proto actually unwind the tag proto change

2022-03-03T16:39:12Z

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: 0b0e2ff10356 ("net: dsa: restore error path of dsa_tree_change_tag_proto") Signed-off-by: Vladimir Oltean Link: https://lore.kernel.org/r/20220303154249.1854436-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski

net: dsa: restore error path of dsa_tree_change_tag_proto

2022-03-02T02:26:21Z

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: dc452a471dba ("net: dsa: introduce tagger-owned storage for private and shared data") Signed-off-by: Vladimir Oltean Link: https://lore.kernel.org/r/20220228141715.146485-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski

net: dsa: fix panic when DSA master device unbinds on shutdown

2022-02-09T13:21:39Z

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: 0650bf52b31f ("net: dsa: be compatible with masters which unregister on shutdown") Reported-by: Rafael Richter Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller

net: dsa: setup master before ports

2022-01-06T11:59:10Z

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 Signed-off-by: David S. Miller

net: dsa: first set up shared ports, then non-shared ports

2022-01-06T11:59:10Z

After commit a57d8c217aad ("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 Signed-off-by: David S. Miller

net: dsa: hold rtnl_mutex when calling dsa_master_{setup,teardown}

2022-01-06T11:59:10Z

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 Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller