linux/fs/xfs/libxfs/xfs_cksum.h
Darrick J. Wong c8ce540db5 xfs: remove double-underscore integer types
This is a purely mechanical patch that removes the private
__{u,}int{8,16,32,64}_t typedefs in favor of using the system
{u,}int{8,16,32,64}_t typedefs.  This is the sed script used to perform
the transformation and fix the resulting whitespace and indentation
errors:

s/typedef\t__uint8_t/typedef __uint8_t\t/g
s/typedef\t__uint/typedef __uint/g
s/typedef\t__int\([0-9]*\)_t/typedef int\1_t\t/g
s/__uint8_t\t/__uint8_t\t\t/g
s/__uint/uint/g
s/__int\([0-9]*\)_t\t/__int\1_t\t\t/g
s/__int/int/g
/^typedef.*int[0-9]*_t;$/d

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2017-06-19 14:11:33 -07:00

82 lines
2.3 KiB
C

#ifndef _XFS_CKSUM_H
#define _XFS_CKSUM_H 1
#define XFS_CRC_SEED (~(uint32_t)0)
/*
* Calculate the intermediate checksum for a buffer that has the CRC field
* inside it. The offset of the 32bit crc fields is passed as the
* cksum_offset parameter. We do not modify the buffer during verification,
* hence we have to split the CRC calculation across the cksum_offset.
*/
static inline uint32_t
xfs_start_cksum_safe(char *buffer, size_t length, unsigned long cksum_offset)
{
uint32_t zero = 0;
uint32_t crc;
/* Calculate CRC up to the checksum. */
crc = crc32c(XFS_CRC_SEED, buffer, cksum_offset);
/* Skip checksum field */
crc = crc32c(crc, &zero, sizeof(__u32));
/* Calculate the rest of the CRC. */
return crc32c(crc, &buffer[cksum_offset + sizeof(__be32)],
length - (cksum_offset + sizeof(__be32)));
}
/*
* Fast CRC method where the buffer is modified. Callers must have exclusive
* access to the buffer while the calculation takes place.
*/
static inline uint32_t
xfs_start_cksum_update(char *buffer, size_t length, unsigned long cksum_offset)
{
/* zero the CRC field */
*(__le32 *)(buffer + cksum_offset) = 0;
/* single pass CRC calculation for the entire buffer */
return crc32c(XFS_CRC_SEED, buffer, length);
}
/*
* Convert the intermediate checksum to the final ondisk format.
*
* The CRC32c calculation uses LE format even on BE machines, but returns the
* result in host endian format. Hence we need to byte swap it back to LE format
* so that it is consistent on disk.
*/
static inline __le32
xfs_end_cksum(uint32_t crc)
{
return ~cpu_to_le32(crc);
}
/*
* Helper to generate the checksum for a buffer.
*
* This modifies the buffer temporarily - callers must have exclusive
* access to the buffer while the calculation takes place.
*/
static inline void
xfs_update_cksum(char *buffer, size_t length, unsigned long cksum_offset)
{
uint32_t crc = xfs_start_cksum_update(buffer, length, cksum_offset);
*(__le32 *)(buffer + cksum_offset) = xfs_end_cksum(crc);
}
/*
* Helper to verify the checksum for a buffer.
*/
static inline int
xfs_verify_cksum(char *buffer, size_t length, unsigned long cksum_offset)
{
uint32_t crc = xfs_start_cksum_safe(buffer, length, cksum_offset);
return *(__le32 *)(buffer + cksum_offset) == xfs_end_cksum(crc);
}
#endif /* _XFS_CKSUM_H */