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e83d565378
207 Commits
| Author | SHA1 | Message | Date | |
|---|---|---|---|---|
Vladimir Oltean
|
e83d565378 |
net: dsa: replay master state events in dsa_tree_{setup,teardown}_master
In order for switch driver to be able to make simple and reliable use of the master tracking operations, they must also be notified of the initial state of the DSA master, not just of the changes. This is because they might enable certain features only during the time when they know that the DSA master is up and running. Therefore, this change explicitly checks the state of the DSA master under the same rtnl_mutex as we were holding during the dsa_master_setup() and dsa_master_teardown() call. The idea being that if the DSA master became operational in between the moment in which it became a DSA master (dsa_master_setup set dev->dsa_ptr) and the moment when we checked for the master being up, there is a chance that we would emit a ->master_state_change() call with no actual state change. We need to avoid that by serializing the concurrent netdevice event with us. If the netdevice event started before, we force it to finish before we begin, because we take rtnl_lock before making netdev_uses_dsa() return true. So we also handle that early event and do nothing on it. Similarly, if the dev_open() attempt is concurrent with us, it will attempt to take the rtnl_mutex, but we're holding it. We'll see that the master flag IFF_UP isn't set, then when we release the rtnl_mutex we'll process the NETDEV_UP notifier. 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> |
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Vladimir Oltean
|
295ab96f47 |
net: dsa: provide switch operations for tracking the master state
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> |
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Vladimir Oltean
|
11fd667dac |
net: dsa: setup master before ports
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>
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Vladimir Oltean
|
1e3f407f3c |
net: dsa: first set up shared ports, then non-shared ports
After commit
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Vladimir Oltean
|
c146f9bc19 |
net: dsa: hold rtnl_mutex when calling dsa_master_{setup,teardown}
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> |
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Vladimir Oltean
|
258030acc9 |
net: dsa: make dsa_switch :: num_ports an unsigned int
Currently, num_ports is declared as size_t, which is defined as
__kernel_ulong_t, therefore it occupies 8 bytes of memory.
Even switches with port numbers in the range of tens are exotic, so
there is no need for this amount of storage.
Additionally, because the max_num_bridges member right above it is also
4 bytes, it means the compiler needs to add padding between the last 2
fields. By reducing the size, we don't need that padding and can reduce
the struct size.
Before:
pahole -C dsa_switch net/dsa/slave.o
struct dsa_switch {
struct device * dev; /* 0 8 */
struct dsa_switch_tree * dst; /* 8 8 */
unsigned int index; /* 16 4 */
u32 setup:1; /* 20: 0 4 */
u32 vlan_filtering_is_global:1; /* 20: 1 4 */
u32 needs_standalone_vlan_filtering:1; /* 20: 2 4 */
u32 configure_vlan_while_not_filtering:1; /* 20: 3 4 */
u32 untag_bridge_pvid:1; /* 20: 4 4 */
u32 assisted_learning_on_cpu_port:1; /* 20: 5 4 */
u32 vlan_filtering:1; /* 20: 6 4 */
u32 pcs_poll:1; /* 20: 7 4 */
u32 mtu_enforcement_ingress:1; /* 20: 8 4 */
/* XXX 23 bits hole, try to pack */
struct notifier_block nb; /* 24 24 */
/* XXX last struct has 4 bytes of padding */
void * priv; /* 48 8 */
void * tagger_data; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
struct dsa_chip_data * cd; /* 64 8 */
const struct dsa_switch_ops * ops; /* 72 8 */
u32 phys_mii_mask; /* 80 4 */
/* XXX 4 bytes hole, try to pack */
struct mii_bus * slave_mii_bus; /* 88 8 */
unsigned int ageing_time_min; /* 96 4 */
unsigned int ageing_time_max; /* 100 4 */
struct dsa_8021q_context * tag_8021q_ctx; /* 104 8 */
struct devlink * devlink; /* 112 8 */
unsigned int num_tx_queues; /* 120 4 */
unsigned int num_lag_ids; /* 124 4 */
/* --- cacheline 2 boundary (128 bytes) --- */
unsigned int max_num_bridges; /* 128 4 */
/* XXX 4 bytes hole, try to pack */
size_t num_ports; /* 136 8 */
/* size: 144, cachelines: 3, members: 27 */
/* sum members: 132, holes: 2, sum holes: 8 */
/* sum bitfield members: 9 bits, bit holes: 1, sum bit holes: 23 bits */
/* paddings: 1, sum paddings: 4 */
/* last cacheline: 16 bytes */
};
After:
pahole -C dsa_switch net/dsa/slave.o
struct dsa_switch {
struct device * dev; /* 0 8 */
struct dsa_switch_tree * dst; /* 8 8 */
unsigned int index; /* 16 4 */
u32 setup:1; /* 20: 0 4 */
u32 vlan_filtering_is_global:1; /* 20: 1 4 */
u32 needs_standalone_vlan_filtering:1; /* 20: 2 4 */
u32 configure_vlan_while_not_filtering:1; /* 20: 3 4 */
u32 untag_bridge_pvid:1; /* 20: 4 4 */
u32 assisted_learning_on_cpu_port:1; /* 20: 5 4 */
u32 vlan_filtering:1; /* 20: 6 4 */
u32 pcs_poll:1; /* 20: 7 4 */
u32 mtu_enforcement_ingress:1; /* 20: 8 4 */
/* XXX 23 bits hole, try to pack */
struct notifier_block nb; /* 24 24 */
/* XXX last struct has 4 bytes of padding */
void * priv; /* 48 8 */
void * tagger_data; /* 56 8 */
/* --- cacheline 1 boundary (64 bytes) --- */
struct dsa_chip_data * cd; /* 64 8 */
const struct dsa_switch_ops * ops; /* 72 8 */
u32 phys_mii_mask; /* 80 4 */
/* XXX 4 bytes hole, try to pack */
struct mii_bus * slave_mii_bus; /* 88 8 */
unsigned int ageing_time_min; /* 96 4 */
unsigned int ageing_time_max; /* 100 4 */
struct dsa_8021q_context * tag_8021q_ctx; /* 104 8 */
struct devlink * devlink; /* 112 8 */
unsigned int num_tx_queues; /* 120 4 */
unsigned int num_lag_ids; /* 124 4 */
/* --- cacheline 2 boundary (128 bytes) --- */
unsigned int max_num_bridges; /* 128 4 */
unsigned int num_ports; /* 132 4 */
/* size: 136, cachelines: 3, members: 27 */
/* sum members: 128, holes: 1, sum holes: 4 */
/* sum bitfield members: 9 bits, bit holes: 1, sum bit holes: 23 bits */
/* paddings: 1, sum paddings: 4 */
/* last cacheline: 8 bytes */
};
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Vladimir Oltean
|
7f2973149c |
net: dsa: make tagging protocols connect to individual switches from a tree
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> |
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Vladimir Oltean
|
dc452a471d |
net: dsa: introduce tagger-owned storage for private and shared data
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> |
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Vladimir Oltean
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d3eed0e57d |
net: dsa: keep the bridge_dev and bridge_num as part of the same structure
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>
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Vladimir Oltean
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947c8746e2 |
net: dsa: assign a bridge number even without TX forwarding offload
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> |
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Vladimir Oltean
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3f9bb0301d |
net: dsa: make dp->bridge_num one-based
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
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Vladimir Oltean
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338a3a4745 |
net: dsa: introduce locking for the address lists on CPU and DSA ports
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>
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David S. Miller
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2d7e73f09f |
Revert "Merge branch 'dsa-rtnl'"
This reverts commit |
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Vladimir Oltean
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d3bd892437 |
net: dsa: introduce locking for the address lists on CPU and DSA ports
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>
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David S. Miller
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bdfa75ad70 |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
Lots of simnple overlapping additions. With a build fix from Stephen Rothwell. Signed-off-by: David S. Miller <davem@davemloft.net> |
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Vladimir Oltean
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65c563a677 |
net: dsa: do not open-code dsa_switch_for_each_port
Find the remaining iterators over dst->ports that only filter for the ports belonging to a certain switch, and replace those with the dsa_switch_for_each_port helper that we have now. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Vladimir Oltean
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d0004a020b |
net: dsa: remove the "dsa_to_port in a loop" antipattern from the core
Ever since Vivien's conversion of the ds->ports array into a dst->ports
list, and the introduction of dsa_to_port, iterations through the ports
of a switch became quadratic whenever dsa_to_port was needed.
dsa_to_port can either be called directly, or indirectly through the
dsa_is_{user,cpu,dsa,unused}_port helpers.
Use the newly introduced dsa_switch_for_each_port() iteration macro
that works with the iterator variable being a struct dsa_port *dp
directly, and not an int i. It is an expensive variable to go from i to
dp, but cheap to go from dp to i.
This macro iterates through the entire ds->dst->ports list and filters
by the ports belonging just to the switch provided as argument.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Reviewed-by: Florian Fainelli <f.fainelli@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Christophe JAILLET
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ba69fd9101 |
net: dsa: Fix an error handling path in 'dsa_switch_parse_ports_of()'
If we return before the end of the 'for_each_child_of_node()' iterator, the
reference taken on 'port' must be released.
Add the missing 'of_node_put()' calls.
Fixes:
|
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Jakub Kicinski
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e15f5972b8 |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
tools/testing/selftests/net/ioam6.sh |
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Vladimir Oltean
|
39e222bfd7 |
net: dsa: unregister cross-chip notifier after ds->ops->teardown
To be symmetric with the error unwind path of dsa_switch_setup(), call dsa_switch_unregister_notifier() after ds->ops->teardown. The implication is that ds->ops->teardown cannot emit cross-chip notifiers. For example, currently the dsa_tag_8021q_unregister() call from sja1105_teardown() does not propagate to the entire tree due to this reason. However I cannot find an actual issue caused by this, observed using code inspection. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Link: https://lore.kernel.org/r/20211012123735.2545742-1-vladimir.oltean@nxp.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
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Vladimir Oltean
|
1951b3f19c |
net: dsa: hold rtnl_lock in dsa_switch_setup_tag_protocol
It was a documented fact that ds->ops->change_tag_protocol() offered
rtnetlink mutex protection to the switch driver, since there was an
ASSERT_RTNL right before the call in dsa_switch_change_tag_proto()
(initiated from sysfs).
The blamed commit introduced another call path for
ds->ops->change_tag_protocol() which does not hold the rtnl_mutex.
This is:
dsa_tree_setup
-> dsa_tree_setup_switches
-> dsa_switch_setup
-> dsa_switch_setup_tag_protocol
-> ds->ops->change_tag_protocol()
-> dsa_port_setup
-> dsa_slave_create
-> register_netdevice(slave_dev)
-> dsa_tree_setup_master
-> dsa_master_setup
-> dev->dsa_ptr = cpu_dp
The reason why the rtnl_mutex is held in the sysfs call path is to
ensure that, once the master and all the DSA interfaces are down (which
is required so that no packets flow), they remain down during the
tagging protocol change.
The above calling order illustrates the fact that it should not be risky
to change the initial tagging protocol to the one specified in the
device tree at the given time:
- packets cannot enter the dsa_switch_rcv() packet type handler since
netdev_uses_dsa() for the master will not yet return true, since
dev->dsa_ptr has not yet been populated
- packets cannot enter the dsa_slave_xmit() function because no DSA
interface has yet been registered
So from the DSA core's perspective, holding the rtnl_mutex is indeed not
necessary.
Yet, drivers may need to do things which need rtnl_mutex protection. For
example:
felix_set_tag_protocol
-> felix_setup_tag_8021q
-> dsa_tag_8021q_register
-> dsa_tag_8021q_setup
-> dsa_tag_8021q_port_setup
-> vlan_vid_add
-> ASSERT_RTNL
These drivers do not really have a choice to take the rtnl_mutex
themselves, since in the sysfs case, the rtnl_mutex is already held.
Fixes:
|
||
|
Vladimir Oltean
|
1bec0f0506 |
net: dsa: fix bridge_num not getting cleared after ports leaving the bridge
The dp->bridge_num is zero-based, with -1 being the encoding for an
invalid value. But dsa_bridge_num_put used to check for an invalid value
by comparing bridge_num with 0, which is of course incorrect.
The result is that the bridge_num will never get cleared by
dsa_bridge_num_put, and further port joins to other bridges will get a
bridge_num larger than the previous one, and once all the available
bridges with TX forwarding offload supported by the hardware get
exhausted, the TX forwarding offload feature is simply disabled.
In the case of sja1105, 7 iterations of the loop below are enough to
exhaust the TX forwarding offload bits, and further bridge joins operate
without that feature.
ip link add br0 type bridge vlan_filtering 1
while :; do
ip link set sw0p2 master br0 && sleep 1
ip link set sw0p2 nomaster && sleep 1
done
This issue is enough of an indication that having the dp->bridge_num
invalid encoding be a negative number is prone to bugs, so this will be
changed to a one-based value, with the dp->bridge_num of zero being the
indication of no bridge. However, that is material for net-next.
Fixes:
|
||
Leon Romanovsky
|
bd936bd53b |
net: dsa: Move devlink registration to be last devlink command
This change prevents from users to access device before devlink is fully configured. Signed-off-by: Leon Romanovsky <leonro@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|
Jakub Kicinski
|
2fcd14d0f7 |
Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net
net/mptcp/protocol.c |
||
|
Leon Romanovsky
|
db4278c55f |
devlink: Make devlink_register to be void
devlink_register() can't fail and always returns success, but all drivers are obligated to check returned status anyway. This adds a lot of boilerplate code to handle impossible flow. Make devlink_register() void and simplify the drivers that use that API call. Signed-off-by: Leon Romanovsky <leonro@nvidia.com> Acked-by: Simon Horman <simon.horman@corigine.com> Acked-by: Vladimir Oltean <olteanv@gmail.com> # dsa Reviewed-by: Jiri Pirko <jiri@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|
Vladimir Oltean
|
5135e96a3d |
net: dsa: don't allocate the slave_mii_bus using devres
The Linux device model permits both the ->shutdown and ->remove driver
methods to get called during a shutdown procedure. Example: a DSA switch
which sits on an SPI bus, and the SPI bus driver calls this on its
->shutdown method:
spi_unregister_controller
-> device_for_each_child(&ctlr->dev, NULL, __unregister);
-> spi_unregister_device(to_spi_device(dev));
-> device_del(&spi->dev);
So this is a simple pattern which can theoretically appear on any bus,
although the only other buses on which I've been able to find it are
I2C:
i2c_del_adapter
-> device_for_each_child(&adap->dev, NULL, __unregister_client);
-> i2c_unregister_device(client);
-> device_unregister(&client->dev);
The implication of this pattern is that devices on these buses can be
unregistered after having been shut down. The drivers for these devices
might choose to return early either from ->remove or ->shutdown if the
other callback has already run once, and they might choose that the
->shutdown method should only perform a subset of the teardown done by
->remove (to avoid unnecessary delays when rebooting).
So in other words, the device driver may choose on ->remove to not
do anything (therefore to not unregister an MDIO bus it has registered
on ->probe), because this ->remove is actually triggered by the
device_shutdown path, and its ->shutdown method has already run and done
the minimally required cleanup.
This used to be fine until the blamed commit, but now, the following
BUG_ON triggers:
void mdiobus_free(struct mii_bus *bus)
{
/* For compatibility with error handling in drivers. */
if (bus->state == MDIOBUS_ALLOCATED) {
kfree(bus);
return;
}
BUG_ON(bus->state != MDIOBUS_UNREGISTERED);
bus->state = MDIOBUS_RELEASED;
put_device(&bus->dev);
}
In other words, there is an attempt to free an MDIO bus which was not
unregistered. The attempt to free it comes from the devres release
callbacks of the SPI device, which are executed after the device is
unregistered.
I'm not saying that the fact that MDIO buses allocated using devres
would automatically get unregistered wasn't strange. I'm just saying
that the commit didn't care about auditing existing call paths in the
kernel, and now, the following code sequences are potentially buggy:
(a) devm_mdiobus_alloc followed by plain mdiobus_register, for a device
located on a bus that unregisters its children on shutdown. After
the blamed patch, either both the alloc and the register should use
devres, or none should.
(b) devm_mdiobus_alloc followed by plain mdiobus_register, and then no
mdiobus_unregister at all in the remove path. After the blamed
patch, nobody unregisters the MDIO bus anymore, so this is even more
buggy than the previous case which needs a specific bus
configuration to be seen, this one is an unconditional bug.
In this case, DSA falls into category (a), it tries to be helpful and
registers an MDIO bus on behalf of the switch, which might be on such a
bus. I've no idea why it does it under devres.
It does this on probe:
if (!ds->slave_mii_bus && ds->ops->phy_read)
alloc and register mdio bus
and this on remove:
if (ds->slave_mii_bus && ds->ops->phy_read)
unregister mdio bus
I _could_ imagine using devres because the condition used on remove is
different than the condition used on probe. So strictly speaking, DSA
cannot determine whether the ds->slave_mii_bus it sees on remove is the
ds->slave_mii_bus that _it_ has allocated on probe. Using devres would
have solved that problem. But nonetheless, the existing code already
proceeds to unregister the MDIO bus, even though it might be
unregistering an MDIO bus it has never registered. So I can only guess
that no driver that implements ds->ops->phy_read also allocates and
registers ds->slave_mii_bus itself.
So in that case, if unregistering is fine, freeing must be fine too.
Stop using devres and free the MDIO bus manually. This will make devres
stop attempting to free a still registered MDIO bus on ->shutdown.
Fixes:
|
||
|
Vladimir Oltean
|
e5845aa0ea |
net: dsa: fix dsa_tree_setup error path
Since the blamed commit, dsa_tree_teardown_switches() was split into two
smaller functions, dsa_tree_teardown_switches and dsa_tree_teardown_ports.
However, the error path of dsa_tree_setup stopped calling dsa_tree_teardown_ports.
Fixes:
|
||
|
Vladimir Oltean
|
fd292c189a |
net: dsa: tear down devlink port regions when tearing down the devlink port on error
Commit |
||
|
Vladimir Oltean
|
0650bf52b3 |
net: dsa: be compatible with masters which unregister on shutdown
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:
|
||
|
Vladimir Oltean
|
a57d8c217a |
net: dsa: flush switchdev workqueue before tearing down CPU/DSA ports
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:
|
||
|
Vladimir Oltean
|
f5e165e72b |
net: dsa: track unique bridge numbers across all DSA switch trees
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> |
||
|
Vladimir Oltean
|
724395f4dc |
net: dsa: tag_8021q: don't broadcast during setup/teardown
Currently, on my board with multiple sja1105 switches in disjoint trees
described in commit
|
||
|
Leon Romanovsky
|
919d13a7e4 |
devlink: Set device as early as possible
All kernel devlink implementations call to devlink_alloc() during initialization routine for specific device which is used later as a parent device for devlink_register(). Such late device assignment causes to the situation which requires us to call to device_register() before setting other parameters, but that call opens devlink to the world and makes accessible for the netlink users. Any attempt to move devlink_register() to be the last call generates the following error due to access to the devlink->dev pointer. [ 8.758862] devlink_nl_param_fill+0x2e8/0xe50 [ 8.760305] devlink_param_notify+0x6d/0x180 [ 8.760435] __devlink_params_register+0x2f1/0x670 [ 8.760558] devlink_params_register+0x1e/0x20 The simple change of API to set devlink device in the devlink_alloc() instead of devlink_register() fixes all this above and ensures that prior to call to devlink_register() everything already set. Signed-off-by: Leon Romanovsky <leonro@nvidia.com> Reviewed-by: Jiri Pirko <jiri@nvidia.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|
Vladimir Oltean
|
2c0b03258b |
net: dsa: give preference to local CPU ports
Be there an "H" switch topology, where there are 2 switches connected as
follows:
eth0 eth1
| |
CPU port CPU port
| DSA link |
sw0p0 sw0p1 sw0p2 sw0p3 sw0p4 -------- sw1p4 sw1p3 sw1p2 sw1p1 sw1p0
| | | | | |
user user user user user user
port port port port port port
basically one where each switch has its own CPU port for termination,
but there is also a DSA link in case packets need to be forwarded in
hardware between one switch and another.
DSA insists to see this as a daisy chain topology, basically registering
all network interfaces as sw0p0@eth0, ... sw1p0@eth0 and disregarding
eth1 as a valid DSA master.
This is only half the story, since when asked using dsa_port_is_cpu(),
DSA will respond that sw1p1 is a CPU port, however one which has no
dp->cpu_dp pointing to it. So sw1p1 is enabled, but not used.
Furthermore, be there a driver for switches which support only one
upstream port. This driver iterates through its ports and checks using
dsa_is_upstream_port() whether the current port is an upstream one.
For switch 1, two ports pass the "is upstream port" checks:
- sw1p4 is an upstream port because it is a routing port towards the
dedicated CPU port assigned using dsa_tree_setup_default_cpu()
- sw1p1 is also an upstream port because it is a CPU port, albeit one
that is disabled. This is because dsa_upstream_port() returns:
if (!cpu_dp)
return port;
which means that if @dp does not have a ->cpu_dp pointer (which is a
characteristic of CPU ports themselves as well as unused ports), then
@dp is its own upstream port.
So the driver for switch 1 rightfully says: I have two upstream ports,
but I don't support multiple upstream ports! So let me error out, I
don't know which one to choose and what to do with the other one.
Generally I am against enforcing any default policy in the kernel in
terms of user to CPU port assignment (like round robin or such) but this
case is different. To solve the conundrum, one would have to:
- Disable sw1p1 in the device tree or mark it as "not a CPU port" in
order to comply with DSA's view of this topology as a daisy chain,
where the termination traffic from switch 1 must pass through switch 0.
This is counter-productive because it wastes 1Gbps of termination
throughput in switch 1.
- Disable the DSA link between sw0p4 and sw1p4 and do software
forwarding between switch 0 and 1, and basically treat the switches as
part of disjoint switch trees. This is counter-productive because it
wastes 1Gbps of autonomous forwarding throughput between switch 0 and 1.
- Treat sw0p4 and sw1p4 as user ports instead of DSA links. This could
work, but it makes cross-chip bridging impossible. In this setup we
would need to have 2 separate bridges, br0 spanning the ports of
switch 0, and br1 spanning the ports of switch 1, and the "DSA links
treated as user ports" sw0p4 (part of br0) and sw1p4 (part of br1) are
the gateway ports between one bridge and another. This is hard to
manage from a user's perspective, who wants to have a unified view of
the switching fabric and the ability to transparently add ports to the
same bridge. VLANs would also need to be explicitly managed by the
user on these gateway ports.
So it seems that the only reasonable thing to do is to make DSA prefer
CPU ports that are local to the switch. Meaning that by default, the
user and DSA ports of switch 0 will get assigned to the CPU port from
switch 0 (sw0p1) and the user and DSA ports of switch 1 will get
assigned to the CPU port from switch 1.
The way this solves the problem is that sw1p4 is no longer an upstream
port as far as switch 1 is concerned (it no longer views sw0p1 as its
dedicated CPU port).
So here we are, the first multi-CPU port that DSA supports is also
perhaps the most uneventful one: the individual switches don't support
multiple CPUs, however the DSA switch tree as a whole does have multiple
CPU ports. No user space assignment of user ports to CPU ports is
desirable, necessary, or possible.
Ports that do not have a local CPU port (say there was an extra switch
hanging off of sw0p0) default to the standard implementation of getting
assigned to the first CPU port of the DSA switch tree. Is that good
enough? Probably not (if the downstream switch was hanging off of switch
1, we would most certainly prefer its CPU port to be sw1p1), but in
order to support that use case too, we would need to traverse the
dst->rtable in search of an optimum dedicated CPU port, one that has the
smallest number of hops between dp->ds and dp->cpu_dp->ds. At the
moment, the DSA routing table structure does not keep the number of hops
between dl->dp and dl->link_dp, and while it is probably deducible,
there is zero justification to write that code now. Let's hope DSA will
never have to support that use case.
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
|
||
|
Vladimir Oltean
|
0e8eb9a16e |
net: dsa: rename teardown_default_cpu to teardown_cpu_ports
There is nothing specific to having a default CPU port to what dsa_tree_teardown_default_cpu() does. Even with multiple CPU ports, it would do the same thing: iterate through the ports of this switch tree and reset the ->cpu_dp pointer to NULL. So rename it accordingly. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
||
|
Vladimir Oltean
|
123abc06e7 |
net: dsa: add support for bridge TX forwarding offload
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>
|
||
|
Vladimir Oltean
|
5b22d3669f |
net: dsa: track the number of switches in a tree
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> |
||
|
Vladimir Oltean
|
3f6e32f92a |
net: dsa: reference count the FDB addresses at the cross-chip notifier level
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> |
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Vladimir Oltean
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161ca59d39 |
net: dsa: reference count the MDB entries at the cross-chip notifier level
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.
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sw0p0 sw0p1 sw0p2 sw0p3 sw0p4
[ user ] [ user ] [ user ] [ dsa ] [ cpu ]
[ x ] [ ] [ ] [ ] [ ]
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+---------+
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sw1p0 sw1p1 sw1p2 sw1p3 sw1p4
[ user ] [ user ] [ user ] [ dsa ] [ dsa ]
[ ] [ ] [ ] [ ] [ x ]
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+---------+
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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:
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sw0p0 sw0p1 sw0p2 sw0p3 sw0p4
[ user ] [ user ] [ user ] [ dsa ] [ cpu ]
[ x ] [ ] [ ] [ ] [ ]
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+---------+
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sw1p0 sw1p1 sw1p2 sw1p3 sw1p4
[ user ] [ user ] [ user ] [ dsa ] [ dsa ]
[ ] [ ] [ ] [ ] [ ]
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+---------+
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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>
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Vladimir Oltean
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a8986681cc |
net: dsa: export the dsa_port_is_{user,cpu,dsa} helpers
The difference between dsa_is_user_port and dsa_port_is_user is that the former needs to look up the list of ports of the DSA switch tree in order to find the struct dsa_port, while the latter directly receives it as an argument. dsa_is_user_port is already in widespread use and has its place, so there isn't any chance of converting all callers to a single form. But being able to do: dsa_port_is_user(dp) instead of dsa_is_user_port(dp->ds, dp->index) is much more efficient too, especially when the "dp" comes from an iterator over the DSA switch tree - this reduces the complexity from quadratic to linear. Move these helpers from dsa2.c to include/net/dsa.h so that others can use them too. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Vladimir Oltean
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8674f8d310 |
net: dsa: assert uniqueness of dsa,member properties
The cross-chip notifiers work by comparing each ds->index against the info->sw_index value from the notifier. The ds->index is retrieved from the device tree dsa,member property. If a single tree cross-chip topology does not declare unique switch IDs, this will result in hard-to-debug issues/voodoo effects such as the cross-chip notifier for one switch port also matching the port with the same number from another switch. Check in dsa_switch_parse_member_of() whether the DSA switch tree contains a DSA switch with the index we're preparing to add, before actually adding it. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Reviewed-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Tobias Waldekranz
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deff710703 |
net: dsa: Allow default tag protocol to be overridden from DT
Some combinations of tag protocols and Ethernet controllers are incompatible, and it is hard for the driver to keep track of these. Therefore, allow the device tree author (typically the board vendor) to inform the driver of this fact by selecting an alternate protocol that is known to work. Signed-off-by: Tobias Waldekranz <tobias@waldekranz.com> Reviewed-by: Vladimir Oltean <olteanv@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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Michael Walle
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83216e3988 |
of: net: pass the dst buffer to of_get_mac_address()
of_get_mac_address() returns a "const void*" pointer to a MAC address.
Lately, support to fetch the MAC address by an NVMEM provider was added.
But this will only work with platform devices. It will not work with
PCI devices (e.g. of an integrated root complex) and esp. not with DSA
ports.
There is an of_* variant of the nvmem binding which works without
devices. The returned data of a nvmem_cell_read() has to be freed after
use. On the other hand the return of_get_mac_address() points to some
static data without a lifetime. The trick for now, was to allocate a
device resource managed buffer which is then returned. This will only
work if we have an actual device.
Change it, so that the caller of of_get_mac_address() has to supply a
buffer where the MAC address is written to. Unfortunately, this will
touch all drivers which use the of_get_mac_address().
Usually the code looks like:
const char *addr;
addr = of_get_mac_address(np);
if (!IS_ERR(addr))
ether_addr_copy(ndev->dev_addr, addr);
This can then be simply rewritten as:
of_get_mac_address(np, ndev->dev_addr);
Sometimes is_valid_ether_addr() is used to test the MAC address.
of_get_mac_address() already makes sure, it just returns a valid MAC
address. Thus we can just test its return code. But we have to be
careful if there are still other sources for the MAC address before the
of_get_mac_address(). In this case we have to keep the
is_valid_ether_addr() call.
The following coccinelle patch was used to convert common cases to the
new style. Afterwards, I've manually gone over the drivers and fixed the
return code variable: either used a new one or if one was already
available use that. Mansour Moufid, thanks for that coccinelle patch!
<spml>
@a@
identifier x;
expression y, z;
@@
- x = of_get_mac_address(y);
+ x = of_get_mac_address(y, z);
<...
- ether_addr_copy(z, x);
...>
@@
identifier a.x;
@@
- if (<+... x ...+>) {}
@@
identifier a.x;
@@
if (<+... x ...+>) {
...
}
- else {}
@@
identifier a.x;
expression e;
@@
- if (<+... x ...+>@e)
- {}
- else
+ if (!(e))
{...}
@@
expression x, y, z;
@@
- x = of_get_mac_address(y, z);
+ of_get_mac_address(y, z);
... when != x
</spml>
All drivers, except drivers/net/ethernet/aeroflex/greth.c, were
compile-time tested.
Suggested-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: Michael Walle <michael@walle.cc>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Maxim Kochetkov
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fb6ec87f72 |
net: dsa: Fix type was not set for devlink port
If PHY is not available on DSA port (described at devicetree but absent or
failed to detect) then kernel prints warning after 3700 secs:
[ 3707.948771] ------------[ cut here ]------------
[ 3707.948784] Type was not set for devlink port.
[ 3707.948894] WARNING: CPU: 1 PID: 17 at net/core/devlink.c:8097 0xc083f9d8
We should unregister the devlink port as a user port and
re-register it as an unused port before executing "continue" in case of
dsa_port_setup error.
Fixes:
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George McCollister
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e0c755a45f |
net: dsa: don't assign an error value to tag_ops
Use a temporary variable to hold the return value from
dsa_tag_driver_get() instead of assigning it to dst->tag_ops. Leaving
an error value in dst->tag_ops can result in deferencing an invalid
pointer when a deferred switch configuration happens later.
Fixes:
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David S. Miller
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dc9d87581d | Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net | ||
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Vladimir Oltean
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8fd54a73b7 |
net: dsa: call teardown method on probe failure
Since teardown is supposed to undo the effects of the setup method, it
should be called in the error path for dsa_switch_setup, not just in
dsa_switch_teardown.
Fixes:
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Vladimir Oltean
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53da0ebaad |
net: dsa: allow changing the tag protocol via the "tagging" device attribute
Currently DSA exposes the following sysfs:
$ cat /sys/class/net/eno2/dsa/tagging
ocelot
which is a read-only device attribute, introduced in the kernel as
commit
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Vladimir Oltean
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357f203bb3 |
net: dsa: keep a copy of the tagging protocol in the DSA switch tree
Cascading DSA switches can be done multiple ways. There is the brute force approach / tag stacking, where one upstream switch, located between leaf switches and the host Ethernet controller, will just happily transport the DSA header of those leaf switches as payload. For this kind of setups, DSA works without any special kind of treatment compared to a single switch - they just aren't aware of each other. Then there's the approach where the upstream switch understands the tags it transports from its leaves below, as it doesn't push a tag of its own, but it routes based on the source port & switch id information present in that tag (as opposed to DMAC & VID) and it strips the tag when egressing a front-facing port. Currently only Marvell implements the latter, and Marvell DSA trees contain only Marvell switches. So it is safe to say that DSA trees already have a single tag protocol shared by all switches, and in fact this is what makes the switches able to understand each other. This fact is also implied by the fact that currently, the tagging protocol is reported as part of a sysfs installed on the DSA master and not per port, so it must be the same for all the ports connected to that DSA master regardless of the switch that they belong to. It's time to make this official and enforce it (yes, this also means we won't have any "switch understands tag to some extent but is not able to speak it" hardware oddities that we'll support in the future). This is needed due to the imminent introduction of the dsa_switch_ops:: change_tag_protocol driver API. When that is introduced, we'll have to notify switches of the tagging protocol that they're configured to use. Currently the tag_ops structure pointer is held only for CPU ports. But there are switches which don't have CPU ports and nonetheless still need to be configured. These would be Marvell leaf switches whose upstream port is just a DSA link. How do we inform these of their tagging protocol setup/deletion? One answer to the above would be: iterate through the DSA switch tree's ports once, list the CPU ports, get their tag_ops, then iterate again now that we have it, and notify everybody of that tag_ops. But what to do if conflicts appear between one cpu_dp->tag_ops and another? There's no escaping the fact that conflict resolution needs to be done, so we can be upfront about it. Ease our work and just keep the master copy of the tag_ops inside the struct dsa_switch_tree. Reference counting is now moved to be per-tree too, instead of per-CPU port. There are many places in the data path that access master->dsa_ptr->tag_ops and we would introduce unnecessary performance penalty going through yet another indirection, so keep those right where they are. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> |
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Vladimir Oltean
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886f8e26f5 |
net: dsa: document the existing switch tree notifiers and add a new one
The existence of dsa_broadcast has generated some confusion in the past: https://www.mail-archive.com/netdev@vger.kernel.org/msg365042.html So let's document the existing dsa_port_notify and dsa_broadcast functions and explain when each of them should be used. Also, in fact, the in-between function has always been there but was lacking a name, and is the main reason for this patch: dsa_tree_notify. Refactor dsa_broadcast to use it. This patch also moves dsa_broadcast (a top-level function) to dsa2.c, where it really belonged in the first place, but had no companion so it stood with dsa_port_notify. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Reviewed-by: Florian Fainelli <f.fainelli@gmail.com> Signed-off-by: Jakub Kicinski <kuba@kernel.org> |