fscrypt: define fscrypt_fname_alloc_buffer() to be for presented names

EXPORT_SYMBOL(fscrypt_fname_encrypted_size);

/**

 * fscrypt_fname_crypto_alloc_obuff() -

 * fscrypt_fname_alloc_buffer - allocate a buffer for presented filenames

 *

 * Allocates an output buffer that is sufficient for the crypto operation

 * specified by the context and the direction.

 * Allocate a buffer that is large enough to hold any decrypted or encoded

 * filename (null-terminated), for the given maximum encrypted filename length.

 *

 * Return: 0 on success, -errno on failure

 */

int fscrypt_fname_alloc_buffer(const struct inode *inode,

				u32 ilen, struct fscrypt_str *crypto_str)

			       u32 max_encrypted_len,

			       struct fscrypt_str *crypto_str)

{

	u32 olen = fscrypt_fname_encrypted_size(inode, ilen);

	const u32 max_encoded_len =

		max_t(u32, BASE64_CHARS(FSCRYPT_FNAME_MAX_UNDIGESTED_SIZE),

		      1 + BASE64_CHARS(sizeof(struct fscrypt_digested_name)));

	u32 max_presented_len;

	crypto_str->len = olen;

	olen = max(olen, max_encoded_len);

	max_presented_len = max(max_encoded_len, max_encrypted_len);

	/*

	 * Allocated buffer can hold one more character to null-terminate the

	 * string

	 */

	crypto_str->name = kmalloc(olen + 1, GFP_NOFS);

	if (!(crypto_str->name))

	crypto_str->name = kmalloc(max_presented_len + 1, GFP_NOFS);

	if (!crypto_str->name)

		return -ENOMEM;

	crypto_str->len = max_presented_len;

	return 0;

}

EXPORT_SYMBOL(fscrypt_fname_alloc_buffer);

/**

 * fscrypt_fname_crypto_free_buffer() -

 * fscrypt_fname_free_buffer - free the buffer for presented filenames

 *

 * Frees the buffer allocated for crypto operation.

 * Free the buffer allocated by fscrypt_fname_alloc_buffer().

 */

void fscrypt_fname_free_buffer(struct fscrypt_str *crypto_str)

{

}

static inline int fscrypt_fname_alloc_buffer(const struct inode *inode,

					     u32 ilen,

					     u32 max_encrypted_len,

					     struct fscrypt_str *crypto_str)

{

	return -EOPNOTSUPP;