diff options
| -rw-r--r-- | drivers/md/md.c | 31 |
1 files changed, 29 insertions, 2 deletions
diff --git a/drivers/md/md.c b/drivers/md/md.c index 64b35cbf315..bad324171ca 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -590,14 +590,41 @@ abort: return ret; } + +static u32 md_csum_fold(u32 csum) +{ + csum = (csum & 0xffff) + (csum >> 16); + return (csum & 0xffff) + (csum >> 16); +} + static unsigned int calc_sb_csum(mdp_super_t * sb) { + u64 newcsum = 0; + u32 *sb32 = (u32*)sb; + int i; unsigned int disk_csum, csum; disk_csum = sb->sb_csum; sb->sb_csum = 0; - csum = csum_partial((void *)sb, MD_SB_BYTES, 0); + + for (i = 0; i < MD_SB_BYTES/4 ; i++) + newcsum += sb32[i]; + csum = (newcsum & 0xffffffff) + (newcsum>>32); + + +#ifdef CONFIG_ALPHA + /* This used to use csum_partial, which was wrong for several + * reasons including that different results are returned on + * different architectures. It isn't critical that we get exactly + * the same return value as before (we always csum_fold before + * testing, and that removes any differences). However as we + * know that csum_partial always returned a 16bit value on + * alphas, do a fold to maximise conformity to previous behaviour. + */ + sb->sb_csum = md_csum_fold(disk_csum); +#else sb->sb_csum = disk_csum; +#endif return csum; } @@ -685,7 +712,7 @@ static int super_90_load(mdk_rdev_t *rdev, mdk_rdev_t *refdev, int minor_version if (sb->raid_disks <= 0) goto abort; - if (csum_fold(calc_sb_csum(sb)) != csum_fold(sb->sb_csum)) { + if (md_csum_fold(calc_sb_csum(sb)) != md_csum_fold(sb->sb_csum)) { printk(KERN_WARNING "md: invalid superblock checksum on %s\n", b); goto abort; |