On Tue, Sep 28, 2021 at 05:14:55PM -0700, Andrii Nakryiko wrote:

So for Bloom filter you get performance advantage from a dedicated map
(due to having just 1 helper call to do N hashing operations). For
pure bitset, there seems to be little benefit at all because it is
basically ARRAY.

I brought up bitset only as an idea to make bloomfilter map a bit more
generic and was looking for feedback whether to call the new map
"bitset that allows bloomfilter operations" or call it
"bloomfilter that simplifies to bitset" with nr_hashes=0.

It sounds that using bloomfilter as a base name fits better.

I haven't found SPDX header or any mention of GPL in
include/linux/jhash.h, so I assumed someone can just copy paste the
code (given the references to public domain). Seems like that's not
the case? Just curious about implications, license-wise, if there is
no SPDX? Is it still considered GPL?

I believe so. Every project that copy pasted jhash from the kernel
add SPDX gpl-2 to its source.