The struct aead_instance is meant to extend struct crypto_instance
by incorporating the extra members of struct aead_alg. However,
the current layout which is copied from shash/ahash does not specify
the struct fully. In particular only aead_alg is present.
For shash/ahash this works because users there add extra headroom
to sizeof(struct crypto_instance) when allocating the instance.
Unfortunately for aead, this bit was lost when the new aead_instance
was added.
Rather than fixing it like shash/ahash, this patch simply expands
struct aead_instance to contain what is supposed to be there, i.e.,
adding struct crypto_instance.
In order to not break existing AEAD users, this is done through an
anonymous union.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
f5d8660acb