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Currently the following script: 1. ip link add br0 type bridge vlan_filtering 1 && ip link set br0 up 2. ip link set swp2 up && ip link set swp2 master br0 3. ip link set swp3 up && ip link set swp3 master br0 4. ip link set swp4 up && ip link set swp4 master br0 5. bridge vlan del dev swp2 vid 1 6. bridge vlan del dev swp3 vid 1 7. ip link set swp4 nomaster 8. ip link set swp3 nomaster produces the following output: [ 641.010738] sja1105 spi0.1: port 2 failed to delete 00:1f:7b:63:02:48 vid 1 from fdb: -2 [ swp2, swp3 and br0 all have the same MAC address, the one listed above ] In short, this happens because the number of FDB entry additions notified to switchdev is unbalanced with the number of deletions. At step 1, the bridge has a random MAC address. At step 2, the br_fdb_replay of swp2 receives this initial MAC address. Then the bridge inherits the MAC address of swp2 via br_fdb_change_mac_address(), and it notifies switchdev (only swp2 at this point) of the deletion of the random MAC address and the addition of 00:1f:7b:63:02:48 as a local FDB entry with fdb->dst == swp2, in VLANs 0 and the default_pvid (1). During step 7: del_nbp -> br_fdb_delete_by_port(br, p, vid=0, do_all=1); -> fdb_delete_local(br, p, f); br_fdb_delete_by_port() deletes all entries towards the ports, regardless of vid, because do_all is 1. fdb_delete_local() has logic to migrate local FDB entries deleted from one port to another port which shares the same MAC address and is in the same VLAN, or to the bridge device itself. This migration happens without notifying switchdev of the deletion on the old port and the addition on the new one, just fdb->dst is changed and the added_by_user flag is cleared. In the example above, the del_nbp(swp4) causes the "addr 00:1f:7b:63:02:48 vid 1" local FDB entry with fdb->dst == swp4 that existed up until then to be migrated directly towards the bridge (fdb->dst == NULL). This is because it cannot be migrated to any of the other ports (swp2 and swp3 are not in VLAN 1). After the migration to br0 takes place, swp4 requests a deletion replay of all FDB entries. Since the "addr 00:1f:7b:63:02:48 vid 1" entry now point towards the bridge, a deletion of it is replayed. There was just a prior addition of this address, so the switchdev driver deletes this entry. Then, the del_nbp(swp3) at step 8 triggers another br_fdb_replay, and switchdev is notified again to delete "addr 00:1f:7b:63:02:48 vid 1". But it can't because it no longer has it, so it returns -ENOENT. There are other possibilities to trigger this issue, but this is by far the simplest to explain. To fix this, we must avoid the situation where the addition of an FDB entry is notified to switchdev as a local entry on a port, and the deletion is notified on the bridge itself. Considering that the 2 types of FDB entries are completely equivalent and we cannot have the same MAC address as a local entry on 2 bridge ports, or on a bridge port and pointing towards the bridge at the same time, it makes sense to hide away from switchdev completely the fact that a local FDB entry is associated with a given bridge port at all. Just say that it points towards the bridge, it should make no difference whatsoever to the switchdev driver and should even lead to a simpler overall implementation, will less cases to handle. This also avoids any modification at all to the core bridge driver, just what is reported to switchdev changes. With the local/permanent entries on bridge ports being already reported to user space, it is hard to believe that the bridge behavior can change in any backwards-incompatible way such as making all local FDB entries point towards the bridge. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net> |
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| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
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| Makefile | ||
| README | ||
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.