crypto: cipher - remove crt_u.cipher (struct cipher_tfm)

Of the three fields in crt_u.cipher (struct cipher_tfm), ->cit_setkey()
is pointless because it always points to setkey() in crypto/cipher.c.

->cit_decrypt_one() and ->cit_encrypt_one() are slightly less pointless,
since if the algorithm doesn't have an alignmask, they are set directly
to ->cia_encrypt() and ->cia_decrypt().  However, this "optimization"
isn't worthwhile because:

- The "cipher" algorithm type is the only algorithm still using crt_u,
  so it's bloating every struct crypto_tfm for every algorithm type.

- If the algorithm has an alignmask, this "optimization" actually makes
  things slower, as it causes 2 indirect calls per block rather than 1.

- It adds extra code complexity.

- Some templates already call ->cia_encrypt()/->cia_decrypt() directly
  instead of going through ->cit_encrypt_one()/->cit_decrypt_one().

- The "cipher" algorithm type never gives optimal performance anyway.
  For that, a higher-level type such as skcipher needs to be used.

Therefore, just remove the extra indirection, and make
crypto_cipher_setkey(), crypto_cipher_encrypt_one(), and
crypto_cipher_decrypt_one() be direct calls into crypto/cipher.c.

Also remove the unused function crypto_cipher_cast().

Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

include/linux/crypto.h

@@ -599,23 +599,10 @@ int crypto_has_alg(const char *name, u32 type, u32 mask);
  * crypto_free_*(), as well as the various helpers below.
  */
 
-struct cipher_tfm {
-	int (*cit_setkey)(struct crypto_tfm *tfm,
-	                  const u8 *key, unsigned int keylen);
-	void (*cit_encrypt_one)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
-	void (*cit_decrypt_one)(struct crypto_tfm *tfm, u8 *dst, const u8 *src);
-};
-
-#define crt_cipher	crt_u.cipher
-
 struct crypto_tfm {
 
 	u32 crt_flags;
 	
-	union {
-		struct cipher_tfm cipher;
-	} crt_u;
-
 	void (*exit)(struct crypto_tfm *tfm);
 	
 	struct crypto_alg *__crt_alg;
@@ -752,12 +739,6 @@ static inline struct crypto_cipher *__crypto_cipher_cast(struct crypto_tfm *tfm)
 	return (struct crypto_cipher *)tfm;
 }
 
-static inline struct crypto_cipher *crypto_cipher_cast(struct crypto_tfm *tfm)
-{
-	BUG_ON(crypto_tfm_alg_type(tfm) != CRYPTO_ALG_TYPE_CIPHER);
-	return __crypto_cipher_cast(tfm);
-}
-
 /**
  * crypto_alloc_cipher() - allocate single block cipher handle
  * @alg_name: is the cra_name / name or cra_driver_name / driver name of the
@@ -815,11 +796,6 @@ static inline int crypto_has_cipher(const char *alg_name, u32 type, u32 mask)
 	return crypto_has_alg(alg_name, type, mask);
 }
 
-static inline struct cipher_tfm *crypto_cipher_crt(struct crypto_cipher *tfm)
-{
-	return &crypto_cipher_tfm(tfm)->crt_cipher;
-}
-
 /**
  * crypto_cipher_blocksize() - obtain block size for cipher
  * @tfm: cipher handle
@@ -873,12 +849,8 @@ static inline void crypto_cipher_clear_flags(struct crypto_cipher *tfm,
  *
  * Return: 0 if the setting of the key was successful; < 0 if an error occurred
  */
-static inline int crypto_cipher_setkey(struct crypto_cipher *tfm,
-                                       const u8 *key, unsigned int keylen)
-{
-	return crypto_cipher_crt(tfm)->cit_setkey(crypto_cipher_tfm(tfm),
-						  key, keylen);
-}
+int crypto_cipher_setkey(struct crypto_cipher *tfm,
+			 const u8 *key, unsigned int keylen);
 
 /**
  * crypto_cipher_encrypt_one() - encrypt one block of plaintext
@@ -889,12 +861,8 @@ static inline int crypto_cipher_setkey(struct crypto_cipher *tfm,
  * Invoke the encryption operation of one block. The caller must ensure that
  * the plaintext and ciphertext buffers are at least one block in size.
  */
-static inline void crypto_cipher_encrypt_one(struct crypto_cipher *tfm,
-					     u8 *dst, const u8 *src)
-{
-	crypto_cipher_crt(tfm)->cit_encrypt_one(crypto_cipher_tfm(tfm),
-						dst, src);
-}
+void crypto_cipher_encrypt_one(struct crypto_cipher *tfm,
+			       u8 *dst, const u8 *src);
 
 /**
  * crypto_cipher_decrypt_one() - decrypt one block of ciphertext
@@ -905,12 +873,8 @@ static inline void crypto_cipher_encrypt_one(struct crypto_cipher *tfm,
  * Invoke the decryption operation of one block. The caller must ensure that
  * the plaintext and ciphertext buffers are at least one block in size.
  */
-static inline void crypto_cipher_decrypt_one(struct crypto_cipher *tfm,
-					     u8 *dst, const u8 *src)
-{
-	crypto_cipher_crt(tfm)->cit_decrypt_one(crypto_cipher_tfm(tfm),
-						dst, src);
-}
+void crypto_cipher_decrypt_one(struct crypto_cipher *tfm,
+			       u8 *dst, const u8 *src);
 
 static inline struct crypto_comp *__crypto_comp_cast(struct crypto_tfm *tfm)
 {