Where exactly will arch_fast_hash be used

[Herbert Xu <herbert@gondor.apana.org.au>]

Hi:

While working on rhashtable it came to me that this whole concept
of arch_fast_hash is flawed.  CRCs are linear functions so it's
fairly easy for an attacker to identify collisions or at least
eliminate a large amount of search space (e.g., controlling the
last bit of the hash result is almost trivial, even when you add
a random seed).

So what exactly are we going to use arch_fast_hash for? Presumably
it's places where security is never goint to be an issue, right?

Even if security wasn't an issue, straight CRC32 has really poor
lower-order bit distribution, which makes it a terrible choice for
a hash table that simply uses the lower-order bits.

Cheers,
-- 
Email: Herbert Xu <herbert@gondor.apana.org.au>
Home Page: http://gondor.apana.org.au/~herbert/
PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt