Dan Williams wrote:
> + * @scfs: array of source coefficients used in GF-multiplication
Array of source coefficients? Are you doing a vector-vector
multiplication here?
Given this code:
> for (d = 0; d < len; d++) {
> + wq = wp = ptrs[0][d];
> + for (z = 1; z < src_cnt; z++) {
> + wd = ptrs[z][d];
> + wp ^= wd;
> + wq ^= raid6_gfmul[scfs[z]][wd];
> + }
... it kinds of looks like that.
This is really quite expensive! The whole point of the restore code
that exists is that we never do a two-dimensional lookup, instead
caching a pointer to the multiplication table that we intend to use,
because the RAID-6 code only ever contains scalar-vector multiplications.
I really don't get this, and I think it's broken.
-hpa
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