fscrypt: clean up comments in bio.c

// SPDX-License-Identifier: GPL-2.0

/*

 * This contains encryption functions for per-file encryption.

 * Utility functions for file contents encryption/decryption on

 * block device-based filesystems.

 *

 * Copyright (C) 2015, Google, Inc.

 * Copyright (C) 2015, Motorola Mobility

 *

 * Written by Michael Halcrow, 2014.

 *

 * Filename encryption additions

 *	Uday Savagaonkar, 2014

 * Encryption policy handling additions

 *	Ildar Muslukhov, 2014

 * Add fscrypt_pullback_bio_page()

 *	Jaegeuk Kim, 2015.

 *

 * This has not yet undergone a rigorous security audit.

 *

 * The usage of AES-XTS should conform to recommendations in NIST

 * Special Publication 800-38E and IEEE P1619/D16.

 */

#include <linux/pagemap.h>

#include <linux/namei.h>

#include "fscrypt_private.h"

/**

 * fscrypt_decrypt_bio() - decrypt the contents of a bio

 * @bio: the bio to decrypt

 *

 * Decrypt the contents of a "read" bio following successful completion of the

 * underlying disk read.  The bio must be reading a whole number of blocks of an

 * encrypted file directly into the page cache.  If the bio is reading the

 * ciphertext into bounce pages instead of the page cache (for example, because

 * the file is also compressed, so decompression is required after decryption),

 * then this function isn't applicable.  This function may sleep, so it must be

 * called from a workqueue rather than from the bio's bi_end_io callback.

 *

 * This function sets PG_error on any pages that contain any blocks that failed

 * to be decrypted.  The filesystem must not mark such pages uptodate.

 */

void fscrypt_decrypt_bio(struct bio *bio)

{

	struct bio_vec *bv;