A Reed-Solomon code with minimum distance d can correct any error and
erasure pattern that satisfies 2 * #error + #erasures < d. If the
error correction capacity is exceeded, then correct decoding cannot be
guaranteed. The decoder must, however, return a valid codeword or report
failure.
There are two main tests:
- Check for correct behaviour up to the error correction capacity
- Check for correct behaviour beyond error corrupted capacity
Both tests are simple:
1. Generate random data
2. Encode data with the chosen code
3. Add errors and erasures to data
4. Decode the corrupted word
5. Check for correct behaviour
When testing up to capacity we test for:
- Correct decoding
- Correct return value (i.e. the number of corrected symbols)
- That the returned error positions are correct
There are two kinds of erasures; the erased symbol can be corrupted or
not. When counting the number of corrected symbols, erasures without
symbol corruption should not be counted. Similarly, the returned error
positions should only include positions where a correction is necessary.
We run the up to capacity tests for three different interfaces of
decode_rs:
- Use the correction buffers
- Use the correction buffers with syndromes provided by the caller
- Error correction in place (does not check the error positions)
When testing beyond capacity test for silent failures. A silent failure is
when the decoder returns success but the returned word is not a valid
codeword.
There are a couple of options for the tests:
- Verbosity.
- Whether to test for correct behaviour beyond capacity. Default is to
test beyond capacity.
- Whether to allow erasures without symbol corruption. Defaults to yes.
Note that the tests take a couple of minutes to complete.
Signed-off-by: Ferdinand Blomqvist <ferdinand.blomqvist@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190620141039.9874-2-ferdinand.blomqvist@gmail.com
Add SPDX license identifiers to all Make/Kconfig files which:
- Have no license information of any form
These files fall under the project license, GPL v2 only. The resulting SPDX
license identifier is:
GPL-2.0-only
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Ferdinand Blomqvist