The patch titled
md: stop using csum_partial for checksum calculation in md
has been removed from the -mm tree. Its filename was
md-stop-using-csum_partial-for-checksum-calculation-in-md.patch
This patch was dropped because it was merged into mainline or a subsystem tree
------------------------------------------------------
Subject: md: stop using csum_partial for checksum calculation in md
From: NeilBrown <neilb@xxxxxxx>
If CONFIG_NET is not selected, csum_partial is not exported, so md.ko cannot
use it. We shouldn't really be using csum_partial anyway as it is an
internal-to-networking interface.
So replace it with C code to do the same thing. Speed is not crucial here, so
something simple and correct is best.
Signed-off-by: Neil Brown <neilb@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
drivers/md/md.c | 31 +++++++++++++++++++++++++++++--
1 file changed, 29 insertions(+), 2 deletions(-)
diff -puN drivers/md/md.c~md-stop-using-csum_partial-for-checksum-calculation-in-md drivers/md/md.c
--- a/drivers/md/md.c~md-stop-using-csum_partial-for-checksum-calculation-in-md
+++ a/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 *rde
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;
_
Patches currently in -mm which might be from neilb@xxxxxxx are
origin.patch
freezer-add-try_to_freeze-calls-to-all-kernel-threads.patch
nlmclnt_recovery-dont-use-clone_sighand.patch
introduce-freezer-flags-rev-2.patch
git-md-accel.patch
md-dm-reduce-stack-usage-with-stacked-block-devices.patch
-
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