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The procedure to add a static FDB entry in sja1105 is concurrent with dynamic learning performed on all bridge ports and the CPU port. The switch looks up the FDB from left to right, and also learns dynamically from left to right, so it is possible that between the moment when we pick up a free slot to install an FDB entry, another slot to the left of that one becomes free due to an address ageing out, and that other slot is then immediately used by the switch to learn dynamically the same address as we're trying to add statically. The result is that we succeeded to add our static FDB entry, but it is being shadowed by a dynamic FDB entry to its left, and the switch will behave as if our static FDB entry did not exist. We cannot really prevent this from happening unless we make the entire process to add a static FDB entry a huge critical section where address learning is temporarily disabled on _all_ ports, and then re-enabled according to the configuration done by sja1105_port_set_learning. However, that is kind of disruptive for the operation of the network. What we can do alternatively is to simply read back the FDB for dynamic entries located before our newly added static one, and delete them. This will guarantee that our static FDB entry is now operational. It will still not guarantee that there aren't dynamic FDB entries to the _right_ of that static FDB entry, but at least those entries will age out by themselves since they aren't hit, and won't bother anyone. Fixes: |
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| arch | ||
| 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 | ||
| Kconfig | ||
| MAINTAINERS | ||
| 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.