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Commit 3ba3ba1e authored by Joe Thornber's avatar Joe Thornber Committed by Mike Snitzer
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dm space map common: memcpy the disk root to ensure it's arch aligned 



The metadata_space_map_root passed to sm_ll_open_metadata() may or may
not be arch aligned, use memcpy to ensure it is.  This is not a fast
path so the extra memcpy doesn't hurt us.

Long-term it'd be better to use the kernel's alignment infrastructure to
remove the memcpy()s that are littered across persistent-data (btree,
array, space-maps, etc).

Signed-off-by: default avatarJoe Thornber <ejt@redhat.com>
Signed-off-by: default avatarMike Snitzer <snitzer@redhat.com>
parent 602548bd

drivers/md/persistent-data/dm-space-map-common.c

+11 −5
Original line number Diff line number Diff line
@@ -626,13 +626,19 @@ int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm, 
			void *root_le, size_t len)

{

	int r;

	struct disk_sm_root *smr = root_le;

	struct disk_sm_root smr;



	if (len < sizeof(struct disk_sm_root)) {

		DMERR("sm_metadata root too small");

		return -ENOMEM;

	}



	/*

	 * We don't know the alignment of the root_le buffer, so need to

	 * copy into a new structure.

	 */

	memcpy(&smr, root_le, sizeof(smr));



	r = sm_ll_init(ll, tm);

	if (r < 0)

		return r;
@@ -644,10 +650,10 @@ int sm_ll_open_metadata(struct ll_disk *ll, struct dm_transaction_manager *tm, 
	ll->max_entries = metadata_ll_max_entries;

	ll->commit = metadata_ll_commit;



	ll->nr_blocks = le64_to_cpu(smr->nr_blocks);

	ll->nr_allocated = le64_to_cpu(smr->nr_allocated);

	ll->bitmap_root = le64_to_cpu(smr->bitmap_root);

	ll->ref_count_root = le64_to_cpu(smr->ref_count_root);

	ll->nr_blocks = le64_to_cpu(smr.nr_blocks);

	ll->nr_allocated = le64_to_cpu(smr.nr_allocated);

	ll->bitmap_root = le64_to_cpu(smr.bitmap_root);

	ll->ref_count_root = le64_to_cpu(smr.ref_count_root);



	return ll->open_index(ll);

}