The "ahash" API provides access to both CPU-based and hardware offload-
based implementations of hash algorithms. Typically the former are
implemented as "shash" algorithms under the hood, while the latter are
implemented as "ahash" algorithms. The "ahash" API provides access to
both. Various kernel subsystems use the ahash API because they want to
support hashing hardware offload without using a separate API for it.
Yet, the common case is that a crypto accelerator is not actually being
used, and ahash is just wrapping a CPU-based shash algorithm.
This patch optimizes the ahash API for that common case by eliminating
the extra indirect call for each ahash operation on top of shash.
It also fixes the double-counting of crypto stats in this scenario
(though CONFIG_CRYPTO_STATS should *not* be enabled by anyone interested
in performance anyway...), and it eliminates redundant checking of
CRYPTO_TFM_NEED_KEY. As a bonus, it also shrinks struct crypto_ahash.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
The functions that are involved in implementing the ahash API on top of
an shash algorithm belong better in ahash.c, not in shash.c where they
currently are. Move them.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This patch adds the helpers crypto_clone_ahash and crypto_clone_shash.
They are the hash-specific counterparts of crypto_clone_tfm.
This allows code paths that cannot otherwise allocate a hash tfm
object to do so. Once a new tfm has been obtained its key could
then be changed without impacting other users.
Note that only algorithms that implement clone_tfm can be cloned.
However, all keyless hashes can be cloned by simply reusing the
tfm object.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Move all stat code specific to hash into the hash code.
While we're at it, change the stats so that bytes and counts
are always incremented even in case of error. This allows the
reference counting to be removed as we can now increment the
counters prior to the operation.
After the operation we simply increase the error count if necessary.
This is safe as errors can only occur synchronously (or rather,
the existing code already ignored asynchronous errors which are
only visible to the callback function).
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
