crypto: ahash - optimize performance when wrapping shash

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>

crypto/ahash.c

@@ -27,22 +27,38 @@
 
 #define CRYPTO_ALG_TYPE_AHASH_MASK	0x0000000e
 
-static int shash_async_setkey(struct crypto_ahash *tfm, const u8 *key,
-			      unsigned int keylen)
+static inline struct crypto_istat_hash *ahash_get_stat(struct ahash_alg *alg)
+{
+	return hash_get_stat(&alg->halg);
+}
+
+static inline int crypto_ahash_errstat(struct ahash_alg *alg, int err)
 {
-	struct crypto_shash **ctx = crypto_ahash_ctx(tfm);
+	if (!IS_ENABLED(CONFIG_CRYPTO_STATS))
+		return err;
+
+	if (err && err != -EINPROGRESS && err != -EBUSY)
+		atomic64_inc(&ahash_get_stat(alg)->err_cnt);
 
-	return crypto_shash_setkey(*ctx, key, keylen);
+	return err;
 }
 
-static int shash_async_init(struct ahash_request *req)
+/*
+ * For an ahash tfm that is using an shash algorithm (instead of an ahash
+ * algorithm), this returns the underlying shash tfm.
+ */
+static inline struct crypto_shash *ahash_to_shash(struct crypto_ahash *tfm)
 {
-	struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
-	struct shash_desc *desc = ahash_request_ctx(req);
+	return *(struct crypto_shash **)crypto_ahash_ctx(tfm);
+}
 
-	desc->tfm = *ctx;
+static inline struct shash_desc *prepare_shash_desc(struct ahash_request *req,
+						    struct crypto_ahash *tfm)
+{
+	struct shash_desc *desc = ahash_request_ctx(req);
 
-	return crypto_shash_init(desc);
+	desc->tfm = ahash_to_shash(tfm);
+	return desc;
 }
 
 int shash_ahash_update(struct ahash_request *req, struct shash_desc *desc)
@@ -58,16 +74,6 @@ int shash_ahash_update(struct ahash_request *req, struct shash_desc *desc)
 }
 EXPORT_SYMBOL_GPL(shash_ahash_update);
 
-static int shash_async_update(struct ahash_request *req)
-{
-	return shash_ahash_update(req, ahash_request_ctx(req));
-}
-
-static int shash_async_final(struct ahash_request *req)
-{
-	return crypto_shash_final(ahash_request_ctx(req), req->result);
-}
-
 int shash_ahash_finup(struct ahash_request *req, struct shash_desc *desc)
 {
 	struct crypto_hash_walk walk;
@@ -89,16 +95,6 @@ int shash_ahash_finup(struct ahash_request *req, struct shash_desc *desc)
 }
 EXPORT_SYMBOL_GPL(shash_ahash_finup);
 
-static int shash_async_finup(struct ahash_request *req)
-{
-	struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
-	struct shash_desc *desc = ahash_request_ctx(req);
-
-	desc->tfm = *ctx;
-
-	return shash_ahash_finup(req, desc);
-}
-
 int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
 {
 	unsigned int nbytes = req->nbytes;
@@ -123,42 +119,16 @@ int shash_ahash_digest(struct ahash_request *req, struct shash_desc *desc)
 }
 EXPORT_SYMBOL_GPL(shash_ahash_digest);
 
-static int shash_async_digest(struct ahash_request *req)
-{
-	struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
-	struct shash_desc *desc = ahash_request_ctx(req);
-
-	desc->tfm = *ctx;
-
-	return shash_ahash_digest(req, desc);
-}
-
-static int shash_async_export(struct ahash_request *req, void *out)
-{
-	return crypto_shash_export(ahash_request_ctx(req), out);
-}
-
-static int shash_async_import(struct ahash_request *req, const void *in)
-{
-	struct crypto_shash **ctx = crypto_ahash_ctx(crypto_ahash_reqtfm(req));
-	struct shash_desc *desc = ahash_request_ctx(req);
-
-	desc->tfm = *ctx;
-
-	return crypto_shash_import(desc, in);
-}
-
-static void crypto_exit_shash_ops_async(struct crypto_tfm *tfm)
+static void crypto_exit_ahash_using_shash(struct crypto_tfm *tfm)
 {
 	struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
 
 	crypto_free_shash(*ctx);
 }
 
-static int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
+static int crypto_init_ahash_using_shash(struct crypto_tfm *tfm)
 {
 	struct crypto_alg *calg = tfm->__crt_alg;
-	struct shash_alg *alg = __crypto_shash_alg(calg);
 	struct crypto_ahash *crt = __crypto_ahash_cast(tfm);
 	struct crypto_shash **ctx = crypto_tfm_ctx(tfm);
 	struct crypto_shash *shash;
@@ -172,47 +142,17 @@ static int crypto_init_shash_ops_async(struct crypto_tfm *tfm)
 		return PTR_ERR(shash);
 	}
 
+	crt->using_shash = true;
 	*ctx = shash;
-	tfm->exit = crypto_exit_shash_ops_async;
-
-	crt->init = shash_async_init;
-	crt->update = shash_async_update;
-	crt->final = shash_async_final;
-	crt->finup = shash_async_finup;
-	crt->digest = shash_async_digest;
-	if (crypto_shash_alg_has_setkey(alg))
-		crt->setkey = shash_async_setkey;
+	tfm->exit = crypto_exit_ahash_using_shash;
 
 	crypto_ahash_set_flags(crt, crypto_shash_get_flags(shash) &
 				    CRYPTO_TFM_NEED_KEY);
-
-	crt->export = shash_async_export;
-	crt->import = shash_async_import;
-
 	crt->reqsize = sizeof(struct shash_desc) + crypto_shash_descsize(shash);
 
 	return 0;
 }
 
-static struct crypto_ahash *
-crypto_clone_shash_ops_async(struct crypto_ahash *nhash,
-			     struct crypto_ahash *hash)
-{
-	struct crypto_shash **nctx = crypto_ahash_ctx(nhash);
-	struct crypto_shash **ctx = crypto_ahash_ctx(hash);
-	struct crypto_shash *shash;
-
-	shash = crypto_clone_shash(*ctx);
-	if (IS_ERR(shash)) {
-		crypto_free_ahash(nhash);
-		return ERR_CAST(shash);
-	}
-
-	*nctx = shash;
-
-	return nhash;
-}
-
 static int hash_walk_next(struct crypto_hash_walk *walk)
 {
 	unsigned int offset = walk->offset;
@@ -290,30 +230,54 @@ static int ahash_nosetkey(struct crypto_ahash *tfm, const u8 *key,
 	return -ENOSYS;
 }
 
-static void ahash_set_needkey(struct crypto_ahash *tfm)
+static void ahash_set_needkey(struct crypto_ahash *tfm, struct ahash_alg *alg)
 {
-	const struct hash_alg_common *alg = crypto_hash_alg_common(tfm);
-
-	if (tfm->setkey != ahash_nosetkey &&
-	    !(alg->base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
+	if (alg->setkey != ahash_nosetkey &&
+	    !(alg->halg.base.cra_flags & CRYPTO_ALG_OPTIONAL_KEY))
 		crypto_ahash_set_flags(tfm, CRYPTO_TFM_NEED_KEY);
 }
 
 int crypto_ahash_setkey(struct crypto_ahash *tfm, const u8 *key,
 			unsigned int keylen)
 {
-	int err = tfm->setkey(tfm, key, keylen);
+	if (likely(tfm->using_shash)) {
+		struct crypto_shash *shash = ahash_to_shash(tfm);
+		int err;
 
+		err = crypto_shash_setkey(shash, key, keylen);
 		if (unlikely(err)) {
-		ahash_set_needkey(tfm);
+			crypto_ahash_set_flags(tfm,
+					       crypto_shash_get_flags(shash) &
+					       CRYPTO_TFM_NEED_KEY);
 			return err;
 		}
+	} else {
+		struct ahash_alg *alg = crypto_ahash_alg(tfm);
+		int err;
 
+		err = alg->setkey(tfm, key, keylen);
+		if (unlikely(err)) {
+			ahash_set_needkey(tfm, alg);
+			return err;
+		}
+	}
 	crypto_ahash_clear_flags(tfm, CRYPTO_TFM_NEED_KEY);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(crypto_ahash_setkey);
 
+int crypto_ahash_init(struct ahash_request *req)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+
+	if (likely(tfm->using_shash))
+		return crypto_shash_init(prepare_shash_desc(req, tfm));
+	if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
+		return -ENOKEY;
+	return crypto_ahash_alg(tfm)->init(req);
+}
+EXPORT_SYMBOL_GPL(crypto_ahash_init);
+
 static int ahash_save_req(struct ahash_request *req, crypto_completion_t cplt,
 			  bool has_state)
 {
@@ -377,42 +341,67 @@ static void ahash_restore_req(struct ahash_request *req, int err)
 	kfree_sensitive(subreq);
 }
 
-int crypto_ahash_final(struct ahash_request *req)
+int crypto_ahash_update(struct ahash_request *req)
 {
 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
-	struct hash_alg_common *alg = crypto_hash_alg_common(tfm);
+	struct ahash_alg *alg;
+
+	if (likely(tfm->using_shash))
+		return shash_ahash_update(req, ahash_request_ctx(req));
 
+	alg = crypto_ahash_alg(tfm);
 	if (IS_ENABLED(CONFIG_CRYPTO_STATS))
-		atomic64_inc(&hash_get_stat(alg)->hash_cnt);
+		atomic64_add(req->nbytes, &ahash_get_stat(alg)->hash_tlen);
+	return crypto_ahash_errstat(alg, alg->update(req));
+}
+EXPORT_SYMBOL_GPL(crypto_ahash_update);
+
+int crypto_ahash_final(struct ahash_request *req)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+	struct ahash_alg *alg;
 
-	return crypto_hash_errstat(alg, tfm->final(req));
+	if (likely(tfm->using_shash))
+		return crypto_shash_final(ahash_request_ctx(req), req->result);
+
+	alg = crypto_ahash_alg(tfm);
+	if (IS_ENABLED(CONFIG_CRYPTO_STATS))
+		atomic64_inc(&ahash_get_stat(alg)->hash_cnt);
+	return crypto_ahash_errstat(alg, alg->final(req));
 }
 EXPORT_SYMBOL_GPL(crypto_ahash_final);
 
 int crypto_ahash_finup(struct ahash_request *req)
 {
 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
-	struct hash_alg_common *alg = crypto_hash_alg_common(tfm);
+	struct ahash_alg *alg;
 
+	if (likely(tfm->using_shash))
+		return shash_ahash_finup(req, ahash_request_ctx(req));
+
+	alg = crypto_ahash_alg(tfm);
 	if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
-		struct crypto_istat_hash *istat = hash_get_stat(alg);
+		struct crypto_istat_hash *istat = ahash_get_stat(alg);
 
 		atomic64_inc(&istat->hash_cnt);
 		atomic64_add(req->nbytes, &istat->hash_tlen);
 	}
-
-	return crypto_hash_errstat(alg, tfm->finup(req));
+	return crypto_ahash_errstat(alg, alg->finup(req));
 }
 EXPORT_SYMBOL_GPL(crypto_ahash_finup);
 
 int crypto_ahash_digest(struct ahash_request *req)
 {
 	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
-	struct hash_alg_common *alg = crypto_hash_alg_common(tfm);
+	struct ahash_alg *alg;
 	int err;
 
+	if (likely(tfm->using_shash))
+		return shash_ahash_digest(req, prepare_shash_desc(req, tfm));
+
+	alg = crypto_ahash_alg(tfm);
 	if (IS_ENABLED(CONFIG_CRYPTO_STATS)) {
-		struct crypto_istat_hash *istat = hash_get_stat(alg);
+		struct crypto_istat_hash *istat = ahash_get_stat(alg);
 
 		atomic64_inc(&istat->hash_cnt);
 		atomic64_add(req->nbytes, &istat->hash_tlen);
@@ -421,9 +410,9 @@ int crypto_ahash_digest(struct ahash_request *req)
 	if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
 		err = -ENOKEY;
 	else
-		err = tfm->digest(req);
+		err = alg->digest(req);
 
-	return crypto_hash_errstat(alg, err);
+	return crypto_ahash_errstat(alg, err);
 }
 EXPORT_SYMBOL_GPL(crypto_ahash_digest);
 
@@ -448,7 +437,7 @@ static int ahash_def_finup_finish1(struct ahash_request *req, int err)
 
 	subreq->base.complete = ahash_def_finup_done2;
 
-	err = crypto_ahash_reqtfm(req)->final(subreq);
+	err = crypto_ahash_alg(crypto_ahash_reqtfm(req))->final(subreq);
 	if (err == -EINPROGRESS || err == -EBUSY)
 		return err;
 
@@ -485,13 +474,35 @@ static int ahash_def_finup(struct ahash_request *req)
 	if (err)
 		return err;
 
-	err = tfm->update(req->priv);
+	err = crypto_ahash_alg(tfm)->update(req->priv);
 	if (err == -EINPROGRESS || err == -EBUSY)
 		return err;
 
 	return ahash_def_finup_finish1(req, err);
 }
 
+int crypto_ahash_export(struct ahash_request *req, void *out)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+
+	if (likely(tfm->using_shash))
+		return crypto_shash_export(ahash_request_ctx(req), out);
+	return crypto_ahash_alg(tfm)->export(req, out);
+}
+EXPORT_SYMBOL_GPL(crypto_ahash_export);
+
+int crypto_ahash_import(struct ahash_request *req, const void *in)
+{
+	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
+
+	if (likely(tfm->using_shash))
+		return crypto_shash_import(prepare_shash_desc(req, tfm), in);
+	if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
+		return -ENOKEY;
+	return crypto_ahash_alg(tfm)->import(req, in);
+}
+EXPORT_SYMBOL_GPL(crypto_ahash_import);
+
 static void crypto_ahash_exit_tfm(struct crypto_tfm *tfm)
 {
 	struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
@@ -505,25 +516,12 @@ static int crypto_ahash_init_tfm(struct crypto_tfm *tfm)
 	struct crypto_ahash *hash = __crypto_ahash_cast(tfm);
 	struct ahash_alg *alg = crypto_ahash_alg(hash);
 
-	hash->setkey = ahash_nosetkey;
-
 	crypto_ahash_set_statesize(hash, alg->halg.statesize);
 
 	if (tfm->__crt_alg->cra_type == &crypto_shash_type)
-		return crypto_init_shash_ops_async(tfm);
-
-	hash->init = alg->init;
-	hash->update = alg->update;
-	hash->final = alg->final;
-	hash->finup = alg->finup ?: ahash_def_finup;
-	hash->digest = alg->digest;
-	hash->export = alg->export;
-	hash->import = alg->import;
-
-	if (alg->setkey) {
-		hash->setkey = alg->setkey;
-		ahash_set_needkey(hash);
-	}
+		return crypto_init_ahash_using_shash(tfm);
+
+	ahash_set_needkey(hash, alg);
 
 	if (alg->exit_tfm)
 		tfm->exit = crypto_ahash_exit_tfm;
@@ -641,19 +639,21 @@ struct crypto_ahash *crypto_clone_ahash(struct crypto_ahash *hash)
 	if (IS_ERR(nhash))
 		return nhash;
 
-	nhash->init = hash->init;
-	nhash->update = hash->update;
-	nhash->final = hash->final;
-	nhash->finup = hash->finup;
-	nhash->digest = hash->digest;
-	nhash->export = hash->export;
-	nhash->import = hash->import;
-	nhash->setkey = hash->setkey;
 	nhash->reqsize = hash->reqsize;
 	nhash->statesize = hash->statesize;
 
-	if (tfm->__crt_alg->cra_type != &crypto_ahash_type)
-		return crypto_clone_shash_ops_async(nhash, hash);
+	if (likely(hash->using_shash)) {
+		struct crypto_shash **nctx = crypto_ahash_ctx(nhash);
+		struct crypto_shash *shash;
+
+		shash = crypto_clone_shash(ahash_to_shash(hash));
+		if (IS_ERR(shash)) {
+			err = PTR_ERR(shash);
+			goto out_free_nhash;
+		}
+		*nctx = shash;
+		return nhash;
+	}
 
 	err = -ENOSYS;
 	alg = crypto_ahash_alg(hash);
@@ -687,6 +687,11 @@ static int ahash_prepare_alg(struct ahash_alg *alg)
 	base->cra_type = &crypto_ahash_type;
 	base->cra_flags |= CRYPTO_ALG_TYPE_AHASH;
 
+	if (!alg->finup)
+		alg->finup = ahash_def_finup;
+	if (!alg->setkey)
+		alg->setkey = ahash_nosetkey;
+
 	return 0;
 }
 
@@ -761,7 +766,7 @@ bool crypto_hash_alg_has_setkey(struct hash_alg_common *halg)
 	if (alg->cra_type == &crypto_shash_type)
 		return crypto_shash_alg_has_setkey(__crypto_shash_alg(alg));
 
-	return __crypto_ahash_alg(alg)->setkey != NULL;
+	return __crypto_ahash_alg(alg)->setkey != ahash_nosetkey;
 }
 EXPORT_SYMBOL_GPL(crypto_hash_alg_has_setkey);
 

crypto/hash.h

@@ -12,6 +12,16 @@
 
 #include "internal.h"
 
+static inline struct crypto_istat_hash *hash_get_stat(
+	struct hash_alg_common *alg)
+{
+#ifdef CONFIG_CRYPTO_STATS
+	return &alg->stat;
+#else
+	return NULL;
+#endif
+}
+
 static inline int crypto_hash_report_stat(struct sk_buff *skb,
 					  struct crypto_alg *alg,
 					  const char *type)

crypto/shash.c

@@ -23,7 +23,13 @@ static inline struct crypto_istat_hash *shash_get_stat(struct shash_alg *alg)
 
 static inline int crypto_shash_errstat(struct shash_alg *alg, int err)
 {
-	return crypto_hash_errstat(&alg->halg, err);
+	if (!IS_ENABLED(CONFIG_CRYPTO_STATS))
+		return err;
+
+	if (err && err != -EINPROGRESS && err != -EBUSY)
+		atomic64_inc(&shash_get_stat(alg)->err_cnt);
+
+	return err;
 }
 
 int shash_no_setkey(struct crypto_shash *tfm, const u8 *key,

include/crypto/hash.h

@@ -250,16 +250,7 @@ struct shash_alg {
 #undef HASH_ALG_COMMON_STAT
 
 struct crypto_ahash {
-	int (*init)(struct ahash_request *req);
-	int (*update)(struct ahash_request *req);
-	int (*final)(struct ahash_request *req);
-	int (*finup)(struct ahash_request *req);
-	int (*digest)(struct ahash_request *req);
-	int (*export)(struct ahash_request *req, void *out);
-	int (*import)(struct ahash_request *req, const void *in);
-	int (*setkey)(struct crypto_ahash *tfm, const u8 *key,
-		      unsigned int keylen);
-
+	bool using_shash; /* Underlying algorithm is shash, not ahash */
 	unsigned int statesize;
 	unsigned int reqsize;
 	struct crypto_tfm base;
@@ -513,10 +504,7 @@ int crypto_ahash_digest(struct ahash_request *req);
  *
  * Return: 0 if the export was successful; < 0 if an error occurred
  */
-static inline int crypto_ahash_export(struct ahash_request *req, void *out)
-{
-	return crypto_ahash_reqtfm(req)->export(req, out);
-}
+int crypto_ahash_export(struct ahash_request *req, void *out);
 
 /**
  * crypto_ahash_import() - import message digest state
@@ -529,15 +517,7 @@ static inline int crypto_ahash_export(struct ahash_request *req, void *out)
  *
  * Return: 0 if the import was successful; < 0 if an error occurred
  */
-static inline int crypto_ahash_import(struct ahash_request *req, const void *in)
-{
-	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
-
-	if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
-		return -ENOKEY;
-
-	return tfm->import(req, in);
-}
+int crypto_ahash_import(struct ahash_request *req, const void *in);
 
 /**
  * crypto_ahash_init() - (re)initialize message digest handle
@@ -550,36 +530,7 @@ static inline int crypto_ahash_import(struct ahash_request *req, const void *in)
  *
  * Return: see crypto_ahash_final()
  */
-static inline int crypto_ahash_init(struct ahash_request *req)
-{
-	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
-
-	if (crypto_ahash_get_flags(tfm) & CRYPTO_TFM_NEED_KEY)
-		return -ENOKEY;
-
-	return tfm->init(req);
-}
-
-static inline struct crypto_istat_hash *hash_get_stat(
-	struct hash_alg_common *alg)
-{
-#ifdef CONFIG_CRYPTO_STATS
-	return &alg->stat;
-#else
-	return NULL;
-#endif
-}
-
-static inline int crypto_hash_errstat(struct hash_alg_common *alg, int err)
-{
-	if (!IS_ENABLED(CONFIG_CRYPTO_STATS))
-		return err;
-
-	if (err && err != -EINPROGRESS && err != -EBUSY)
-		atomic64_inc(&hash_get_stat(alg)->err_cnt);
-
-	return err;
-}
+int crypto_ahash_init(struct ahash_request *req);
 
 /**
  * crypto_ahash_update() - add data to message digest for processing
@@ -592,16 +543,7 @@ static inline int crypto_hash_errstat(struct hash_alg_common *alg, int err)
  *
  * Return: see crypto_ahash_final()
  */
-static inline int crypto_ahash_update(struct ahash_request *req)
-{
-	struct crypto_ahash *tfm = crypto_ahash_reqtfm(req);
-	struct hash_alg_common *alg = crypto_hash_alg_common(tfm);
-
-	if (IS_ENABLED(CONFIG_CRYPTO_STATS))
-		atomic64_add(req->nbytes, &hash_get_stat(alg)->hash_tlen);
-
-	return crypto_hash_errstat(alg, tfm->update(req));
-}
+int crypto_ahash_update(struct ahash_request *req);
 
 /**
  * DOC: Asynchronous Hash Request Handle