This patch changes the kfree call to kzfree for async requests.
As the request may contain sensitive data it needs to be zeroed
before it can be reallocated by others.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This patch replaces the full descriptor export with an export of
the partial hash state.  This allows the use of a consistent export
format across all implementations of a given algorithm.

This is useful because a number of cases require the use of the
partial hash state, e.g., PadLock can use the SHA1 hash state
to get around the fact that it can only hash contiguous data
chunks.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

This function is needed by algorithms that don't know their own
block size, e.g., in s390 where the code is common between multiple
versions of SHA.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

We were freeing an offset into the slab object instead of the
start.  This patch fixes it by calling crypto_destroy_tfm which
allows the correct address to be given.
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>

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>

The top-level functions init/update/final were missing for ahash.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

All new crypto interfaces should go into individual files as much
as possible in order to ensure that crypto.h does not collapse under
its own weight.

This patch moves the ahash code into crypto/hash.h and crypto/internal/hash.h
respectively.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>