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

net: dsa: merge rtnl_lock sections in dsa_slave_create

2022-01-06T11:59:09Z

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

net: dsa: reorder PHY initialization with MTU setup in slave.c

2022-01-06T11:59:09Z

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

net: dsa: keep the bridge_dev and bridge_num as part of the same structure

2021-12-08T22:31:16Z

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 Reviewed-by: Alvin Šipraga Signed-off-by: Jakub Kicinski

net: dsa: rename dsa_port_offloads_bridge to dsa_port_offloads_bridge_dev

2021-12-08T22:31:15Z

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 Reviewed-by: Alvin Šipraga Signed-off-by: Jakub Kicinski

net: dsa: hide dp->bridge_dev and dp->bridge_num in the core behind helpers

2021-12-08T22:31:15Z

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 Signed-off-by: Jakub Kicinski

net: dsa: consolidate phylink creation

2021-12-02T02:58:00Z

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) Reviewed-by: Marek Behún Reviewed-by: Andrew Lunn Signed-off-by: Jakub Kicinski

net: dsa: populate supported_interfaces member

2021-11-01T13:06:32Z

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 [tweaked patch and description to add more complete support -- rmk] Signed-off-by: Russell King Signed-off-by: Russell King (Oracle) Signed-off-by: David S. Miller

net: switchdev: merge switchdev_handle_fdb_{add,del}_to_device

2021-10-27T13:54:02Z

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 Reviewed-by: Ido Schimmel Signed-off-by: David S. Miller

net: dsa: stop calling dev_hold in dsa_slave_fdb_event

2021-10-26T14:07:35Z

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 Signed-off-by: David S. Miller

net: dsa: drop rtnl_lock from dsa_slave_switchdev_event_work

2021-10-25T11:59:42Z

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 c9eb3e0f8701 ("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 b117e1e8a86d ("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 Reviewed-by: Florian Fainelli Signed-off-by: David S. Miller