fscrypt: move v1 policy key setup to keysetup_v1.c

In preparation for introducing v2 encryption policies which will find
and derive encryption keys differently from the current v1 encryption
policies, move the v1 policy-specific key setup code from keyinfo.c into
keysetup_v1.c.

Reviewed-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Eric Biggers <ebiggers@google.com>

fs/crypto/Makefile

@@ -1,5 +1,11 @@
 # SPDX-License-Identifier: GPL-2.0-only
 obj-$(CONFIG_FS_ENCRYPTION)	+= fscrypto.o
 
-fscrypto-y := crypto.o fname.o hooks.o keyinfo.o policy.o
+fscrypto-y := crypto.o \
+	      fname.o \
+	      hooks.o \
+	      keyinfo.o \
+	      keysetup_v1.o \
+	      policy.o
+
 fscrypto-$(CONFIG_BLOCK) += bio.o

fs/crypto/fscrypt_private.h

@@ -173,4 +173,21 @@ fscrypt_mode_supports_direct_key(const struct fscrypt_mode *mode)
 	return mode->ivsize >= offsetofend(union fscrypt_iv, nonce);
 }
 
+extern struct crypto_skcipher *
+fscrypt_allocate_skcipher(struct fscrypt_mode *mode, const u8 *raw_key,
+			  const struct inode *inode);
+
+extern int fscrypt_set_derived_key(struct fscrypt_info *ci,
+				   const u8 *derived_key);
+
+/* keysetup_v1.c */
+
+extern void fscrypt_put_direct_key(struct fscrypt_direct_key *dk);
+
+extern int fscrypt_setup_v1_file_key(struct fscrypt_info *ci,
+				     const u8 *raw_master_key);
+
+extern int fscrypt_setup_v1_file_key_via_subscribed_keyrings(
+					struct fscrypt_info *ci);
+
 #endif /* _FSCRYPT_PRIVATE_H */