Module reference counting for shash is incorrect: when
a new shash transformation is created the refcount is not
increased as it should.
Signed-off-by: NAdrian-Ken Rueegsegger <rueegsegger@swiss-it.ch>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Since most cryptographic hash algorithms have no keys, this patch
makes the setkey function optional for ahash and shash.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch allows shash algorithms to be used through the old hash
interface.  This is a transitional measure so we can convert the
underlying algorithms to shash before converting the users across.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

It is often useful to save the partial state of a hash function
so that it can be used as a base for two or more computations.

The most prominent example is HMAC where all hashes start from
a base determined by the key.  Having an import/export interface
means that we only have to compute that base once rather than
for each message.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch allows shash algorithms to be used through the ahash
interface.  This is required before we can convert digest algorithms
over to shash.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

The shash interface replaces the current synchronous hash interface.
It improves over hash in two ways.  Firstly shash is reentrant,
meaning that the same tfm may be used by two threads simultaneously
as all hashing state is stored in a local descriptor.

The other enhancement is that shash no longer takes scatter list
entries.  This is because shash is specifically designed for
synchronous algorithms and as such scatter lists are unnecessary.

All existing hash users will be converted to shash once the
algorithms have been completely converted.

There is also a new finup function that combines update with final.
This will be extended to ahash once the algorithm conversion is
done.

This is also the first time that an algorithm type has their own
registration function.  Existing algorithm types will be converted
to this way in due course.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>