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authorJoe Thornber2015-11-19 13:03:36 +0000
committerMike Snitzer2017-02-16 13:02:54 -0500
commit3ba3ba1e8411532dc4a05b4e8932c9e358d70a44 (patch)
tree163e9a4f68dd4ffddf87ba4b3f92dd67a39a56ef /drivers/md
parent602548bdd5ac4ed7025d992e3ad61a628af4c500 (diff)
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: Joe Thornber <ejt@redhat.com> Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Diffstat (limited to 'drivers/md')
-rw-r--r--drivers/md/persistent-data/dm-space-map-common.c16
1 files changed, 11 insertions, 5 deletions
diff --git a/drivers/md/persistent-data/dm-space-map-common.c b/drivers/md/persistent-data/dm-space-map-common.c
index 4c28608a0c94..829b4ce057d8 100644
--- a/drivers/md/persistent-data/dm-space-map-common.c
+++ b/drivers/md/persistent-data/dm-space-map-common.c
@@ -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);
}