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| author | Tetsuhiro Kohada <kohada.t2@gmail.com> | 2020-05-29 19:14:59 +0900 |
|---|---|---|
| committer | Namjae Jeon <namjae.jeon@samsung.com> | 2020-06-09 16:49:25 +0900 |
| commit | 5875bf287d95314c58add01184f361cc5aa38429 (patch) | |
| tree | 1de468fb69859f1d17eac04c52d125d4761af6f6 /fs/exfat/misc.c | |
| parent | 476189c0ef3b658de3f6b89fd0fdeb6dc451b564 (diff) | |
| download | linux-rpi-5875bf287d95314c58add01184f361cc5aa38429.tar.gz linux-rpi-5875bf287d95314c58add01184f361cc5aa38429.tar.bz2 linux-rpi-5875bf287d95314c58add01184f361cc5aa38429.zip | |
exfat: standardize checksum calculation
To clarify that it is a 16-bit checksum, the parts related to the 16-bit
checksum are renamed and change type to u16.
Furthermore, replace checksum calculation in exfat_load_upcase_table()
with exfat_calc_checksum32().
Signed-off-by: Tetsuhiro Kohada <kohada.t2@gmail.com>
Reviewed-by: Sungjong Seo <sj1557.seo@samsung.com>
Signed-off-by: Namjae Jeon <namjae.jeon@samsung.com>
Diffstat (limited to 'fs/exfat/misc.c')
| -rw-r--r-- | fs/exfat/misc.c | 10 |
1 files changed, 4 insertions, 6 deletions
diff --git a/fs/exfat/misc.c b/fs/exfat/misc.c index b82d2dd5bd7c..17d41f3d3709 100644 --- a/fs/exfat/misc.c +++ b/fs/exfat/misc.c @@ -136,17 +136,15 @@ void exfat_truncate_atime(struct timespec64 *ts) ts->tv_nsec = 0; } -unsigned short exfat_calc_chksum_2byte(void *data, int len, - unsigned short chksum, int type) +u16 exfat_calc_chksum16(void *data, int len, u16 chksum, int type) { int i; - unsigned char *c = (unsigned char *)data; + u8 *c = (u8 *)data; for (i = 0; i < len; i++, c++) { - if (((i == 2) || (i == 3)) && (type == CS_DIR_ENTRY)) + if (unlikely(type == CS_DIR_ENTRY && (i == 2 || i == 3))) continue; - chksum = (((chksum & 1) << 15) | ((chksum & 0xFFFE) >> 1)) + - (unsigned short)*c; + chksum = ((chksum << 15) | (chksum >> 1)) + *c; } return chksum; } |