linux/fs/xfs/scrub/attr.h
Gustavo A. R. Silva 5224f79096 treewide: Replace zero-length arrays with flexible-array members
There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use “flexible array members”[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

This code was transformed with the help of Coccinelle:
(next-20220214$ spatch --jobs $(getconf _NPROCESSORS_ONLN) --sp-file script.cocci --include-headers --dir . > output.patch)

@@
identifier S, member, array;
type T1, T2;
@@

struct S {
  ...
  T1 member;
  T2 array[
- 0
  ];
};

UAPI and wireless changes were intentionally excluded from this patch
and will be sent out separately.

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.16/process/deprecated.html#zero-length-and-one-element-arrays

Link: https://github.com/KSPP/linux/issues/78
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2022-02-17 07:00:39 -06:00

69 lines
1.7 KiB
C

/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* Copyright (C) 2019 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*/
#ifndef __XFS_SCRUB_ATTR_H__
#define __XFS_SCRUB_ATTR_H__
/*
* Temporary storage for online scrub and repair of extended attributes.
*/
struct xchk_xattr_buf {
/* Size of @buf, in bytes. */
size_t sz;
/*
* Memory buffer -- either used for extracting attr values while
* walking the attributes; or for computing attr block bitmaps when
* checking the attribute tree.
*
* Each bitmap contains enough bits to track every byte in an attr
* block (rounded up to the size of an unsigned long). The attr block
* used space bitmap starts at the beginning of the buffer; the free
* space bitmap follows immediately after; and we have a third buffer
* for storing intermediate bitmap results.
*/
uint8_t buf[];
};
/* A place to store attribute values. */
static inline uint8_t *
xchk_xattr_valuebuf(
struct xfs_scrub *sc)
{
struct xchk_xattr_buf *ab = sc->buf;
return ab->buf;
}
/* A bitmap of space usage computed by walking an attr leaf block. */
static inline unsigned long *
xchk_xattr_usedmap(
struct xfs_scrub *sc)
{
struct xchk_xattr_buf *ab = sc->buf;
return (unsigned long *)ab->buf;
}
/* A bitmap of free space computed by walking attr leaf block free info. */
static inline unsigned long *
xchk_xattr_freemap(
struct xfs_scrub *sc)
{
return xchk_xattr_usedmap(sc) +
BITS_TO_LONGS(sc->mp->m_attr_geo->blksize);
}
/* A bitmap used to hold temporary results. */
static inline unsigned long *
xchk_xattr_dstmap(
struct xfs_scrub *sc)
{
return xchk_xattr_freemap(sc) +
BITS_TO_LONGS(sc->mp->m_attr_geo->blksize);
}
#endif /* __XFS_SCRUB_ATTR_H__ */