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authorEric Biggers <ebiggers@google.com>2023-10-18 15:34:55 -0700
committerHerbert Xu <herbert@gondor.apana.org.au>2023-10-27 18:04:24 +0800
commit08debaa5cb31da50725a8cb2f06d3f617a9caa98 (patch)
tree29f3f1b9b6282469e3dda1441ce9e4d8bc16564e /crypto
parenta411f6debeb33e2ec8f5825f0c41497317c0504e (diff)
crypto: shash - eliminate indirect call for default import and export
Most shash algorithms don't have custom ->import and ->export functions, resulting in the memcpy() based default being used. Yet, crypto_shash_import() and crypto_shash_export() still make an indirect call, which is expensive. Therefore, change how the default import and export are called to make it so that crypto_shash_import() and crypto_shash_export() don't do an indirect call in this case. Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'crypto')
-rw-r--r--crypto/shash.c41
1 files changed, 33 insertions, 8 deletions
diff --git a/crypto/shash.c b/crypto/shash.c
index 15fee57cca8e..52420c41db44 100644
--- a/crypto/shash.c
+++ b/crypto/shash.c
@@ -277,17 +277,34 @@ int crypto_shash_tfm_digest(struct crypto_shash *tfm, const u8 *data,
}
EXPORT_SYMBOL_GPL(crypto_shash_tfm_digest);
-static int shash_default_export(struct shash_desc *desc, void *out)
+int crypto_shash_export(struct shash_desc *desc, void *out)
{
- memcpy(out, shash_desc_ctx(desc), crypto_shash_descsize(desc->tfm));
+ struct crypto_shash *tfm = desc->tfm;
+ struct shash_alg *shash = crypto_shash_alg(tfm);
+
+ if (shash->export)
+ return shash->export(desc, out);
+
+ memcpy(out, shash_desc_ctx(desc), crypto_shash_descsize(tfm));
return 0;
}
+EXPORT_SYMBOL_GPL(crypto_shash_export);
-static int shash_default_import(struct shash_desc *desc, const void *in)
+int crypto_shash_import(struct shash_desc *desc, const void *in)
{
- memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(desc->tfm));
+ struct crypto_shash *tfm = desc->tfm;
+ struct shash_alg *shash = crypto_shash_alg(tfm);
+
+ if (crypto_shash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
+ return -ENOKEY;
+
+ if (shash->import)
+ return shash->import(desc, in);
+
+ memcpy(shash_desc_ctx(desc), in, crypto_shash_descsize(tfm));
return 0;
}
+EXPORT_SYMBOL_GPL(crypto_shash_import);
static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
unsigned int keylen)
@@ -666,15 +683,23 @@ static int shash_prepare_alg(struct shash_alg *alg)
base->cra_type = &crypto_shash_type;
base->cra_flags |= CRYPTO_ALG_TYPE_SHASH;
+ /*
+ * Handle missing optional functions. For each one we can either
+ * install a default here, or we can leave the pointer as NULL and check
+ * the pointer for NULL in crypto_shash_*(), avoiding an indirect call
+ * when the default behavior is desired. For ->finup and ->digest we
+ * install defaults, since for optimal performance algorithms should
+ * implement these anyway. On the other hand, for ->import and
+ * ->export the common case and best performance comes from the simple
+ * memcpy of the shash_desc_ctx, so when those pointers are NULL we
+ * leave them NULL and provide the memcpy with no indirect call.
+ */
if (!alg->finup)
alg->finup = shash_default_finup;
if (!alg->digest)
alg->digest = shash_default_digest;
- if (!alg->export) {
- alg->export = shash_default_export;
- alg->import = shash_default_import;
+ if (!alg->export)
alg->halg.statesize = alg->descsize;
- }
if (!alg->setkey)
alg->setkey = shash_no_setkey;