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Commit 4d167f09 authored by NeilBrown's avatar NeilBrown Committed by Linus Torvalds
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md: stop using csum_partial for checksum calculation in md 



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: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e11e93fa

drivers/md/md.c

+29 −2
Original line number Diff line number Diff line
@@ -590,14 +590,41 @@ static int sb_equal(mdp_super_t *sb1, mdp_super_t *sb2) 
	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;