Commit 313a4074 authored by Eric Biggers's avatar Eric Biggers Committed by Herbert Xu
Browse files

crypto: shash - optimize the default digest and finup 



For an shash algorithm that doesn't implement ->digest, currently
crypto_shash_digest() with aligned input makes 5 indirect calls: 1 to
shash_digest_unaligned(), 1 to ->init, 2 to ->update ('alignmask + 1'
bytes, then the rest), then 1 to ->final.  This is true even if the
algorithm implements ->finup.  This is caused by an unnecessary fallback
to code meant to handle unaligned inputs.  In fact,
crypto_shash_digest() already does the needed alignment check earlier.
Therefore, optimize the number of indirect calls for aligned inputs to 3
when the algorithm implements ->finup.  It remains at 5 when the
algorithm implements neither ->finup nor ->digest.

Similarly, for an shash algorithm that doesn't implement ->finup,
currently crypto_shash_finup() with aligned input makes 4 indirect
calls: 1 to shash_finup_unaligned(), 2 to ->update, and
1 to ->final.  Optimize this to 3 calls.

Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent bb40d326

crypto/shash.c

+20 −2
Original line number Diff line number Diff line
@@ -191,6 +191,15 @@ static int shash_finup_unaligned(struct shash_desc *desc, const u8 *data, 
	       shash_final_unaligned(desc, out);

}



static int shash_default_finup(struct shash_desc *desc, const u8 *data,

			       unsigned int len, u8 *out)

{

	struct shash_alg *shash = crypto_shash_alg(desc->tfm);



	return shash->update(desc, data, len) ?:

	       shash->final(desc, out);

}



int crypto_shash_finup(struct shash_desc *desc, const u8 *data,

		       unsigned int len, u8 *out)

{
@@ -224,6 +233,15 @@ static int shash_digest_unaligned(struct shash_desc *desc, const u8 *data, 
	       shash_final_unaligned(desc, out);

}



static int shash_default_digest(struct shash_desc *desc, const u8 *data,

				unsigned int len, u8 *out)

{

	struct shash_alg *shash = crypto_shash_alg(desc->tfm);



	return shash->init(desc) ?:

	       shash->finup(desc, data, len, out);

}



int crypto_shash_digest(struct shash_desc *desc, const u8 *data,

			unsigned int len, u8 *out)

{
@@ -656,9 +674,9 @@ static int shash_prepare_alg(struct shash_alg *alg) 
	base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;



	if (!alg->finup)

		alg->finup = shash_finup_unaligned;

		alg->finup = shash_default_finup;

	if (!alg->digest)

		alg->digest = shash_digest_unaligned;

		alg->digest = shash_default_digest;

	if (!alg->export) {

		alg->export = shash_default_export;

		alg->import = shash_default_import;