This patch moves the default IV generators into their own modules
in order to break a dependency loop between cryptomgr, rng, and
blkcipher.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

For compatibility with dm-crypt initramfs setups it is useful to merge
chainiv/seqiv into the crypto_blkcipher module.  Since they're required
by most algorithms anyway this is an acceptable trade-off.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

This patch makes crypto_alloc_ablkcipher/crypto_grab_skcipher always
return algorithms that are capable of generating their own IVs through
givencrypt and givdecrypt.  Each algorithm may specify its default IV
generator through the geniv field.

For algorithms that do not set the geniv field, the blkcipher layer will
pick a default.  Currently it's chainiv for synchronous algorithms and
eseqiv for asynchronous algorithms.  Note that if these wrappers do not
work on an algorithm then that algorithm must specify its own geniv or
it can't be used at all.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

This patch creates the infrastructure to help the construction of givcipher
templates that wrap around existing blkcipher/ablkcipher algorithms by adding
an IV generator to them.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

This patch introduces the geniv field which indicates the default IV
generator for each algorithm.  It should point to a string that is not
freed as long as the algorithm is registered.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

The scatterwalk infrastructure is used by algorithms so it needs to
move out of crypto for future users that may live in drivers/crypto
or asm/*/crypto.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Up until now we have ablkcipher algorithms have been identified as
type BLKCIPHER with the ASYNC bit set.  This is suboptimal because
ablkcipher refers to two things.  On the one hand it refers to the
top-level ablkcipher interface with requests.  On the other hand it
refers to and algorithm type underneath.

As it is you cannot request a synchronous block cipher algorithm
with the ablkcipher interface on top.  This is a problem because
we want to be able to eventually phase out the blkcipher top-level
interface.

This patch fixes this by making ABLKCIPHER its own type, just as
we have distinct types for HASH and DIGEST.  The type it associated
with the algorithm implementation only.

Which top-level interface is used for synchronous block ciphers is
then determined by the mask that's used.  If it's a specific mask
then the old blkcipher interface is given, otherwise we go with the
new ablkcipher interface.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

This patch adds the helper blkcipher_walk_virt_block which is similar to
blkcipher_walk_virt but uses a supplied block size instead of the block
size of the block cipher.  This is useful for CTR where the block size is
1 but we still want to walk by the block size of the underlying cipher.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Now that the block size is no longer a multiple of the alignment, we need to
increase the kmalloc amount in blkcipher_next_slow to use the aligned block
size.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

Previously we assumed for convenience that the block size is a multiple of
the algorithm's required alignment.  With the pending addition of CTR this
will no longer be the case as the block size will be 1 due to it being a
stream cipher.  However, the alignment requirement will be that of the
underlying implementation which will most likely be greater than 1.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>