fscrypt: unexport fscrypt_get_encryption_info()

Now that fscrypt_get_encryption_info() is only called from files in
fs/crypto/ (due to all key setup now being handled by higher-level
helper functions instead of directly by filesystems), unexport it and
move its declaration to fscrypt_private.h.
Reviewed-by: NAndreas Dilger <adilger@dilger.ca>
Link: https://lore.kernel.org/r/20201203022041.230976-9-ebiggers@kernel.orgSigned-off-by: NEric Biggers <ebiggers@google.com>

fs/crypto/fscrypt_private.h

@@ -571,6 +571,8 @@ int fscrypt_derive_dirhash_key(struct fscrypt_info *ci,
 void fscrypt_hash_inode_number(struct fscrypt_info *ci,
 			       const struct fscrypt_master_key *mk);
 
+int fscrypt_get_encryption_info(struct inode *inode);
+
 /**
  * fscrypt_require_key() - require an inode's encryption key
  * @inode: the inode we need the key for

fs/crypto/keysetup.c

@@ -589,7 +589,6 @@ int fscrypt_get_encryption_info(struct inode *inode)
 		res = 0;
 	return res;
 }
-EXPORT_SYMBOL(fscrypt_get_encryption_info);
 
 /**
  * fscrypt_prepare_new_inode() - prepare to create a new inode in a directory

include/linux/fscrypt.h

@@ -75,7 +75,7 @@ struct fscrypt_operations {
 static inline struct fscrypt_info *fscrypt_get_info(const struct inode *inode)
 {
 	/*
-	 * Pairs with the cmpxchg_release() in fscrypt_get_encryption_info().
+	 * Pairs with the cmpxchg_release() in fscrypt_setup_encryption_info().
 	 * I.e., another task may publish ->i_crypt_info concurrently, executing
 	 * a RELEASE barrier.  We need to use smp_load_acquire() here to safely
 	 * ACQUIRE the memory the other task published.
@@ -200,7 +200,6 @@ int fscrypt_ioctl_remove_key_all_users(struct file *filp, void __user *arg);
 int fscrypt_ioctl_get_key_status(struct file *filp, void __user *arg);
 
 /* keysetup.c */
-int fscrypt_get_encryption_info(struct inode *inode);
 int fscrypt_prepare_new_inode(struct inode *dir, struct inode *inode,
 			      bool *encrypt_ret);
 void fscrypt_put_encryption_info(struct inode *inode);
@@ -408,10 +407,6 @@ static inline int fscrypt_ioctl_get_key_status(struct file *filp,
 }
 
 /* keysetup.c */
-static inline int fscrypt_get_encryption_info(struct inode *inode)
-{
-	return -EOPNOTSUPP;
-}
 
 static inline int fscrypt_prepare_new_inode(struct inode *dir,
 					    struct inode *inode,