In preparation to limit the scope of the list iterator to the list
traversal loop, use a dedicated pointer pointing to the found element [1].
If no break is hit or the list is empty, 'label_ent' will be a bogus
pointer computed based on the head of the list.
In such a case &label_ent->list == &nd_mapping->labels, which will break
the list properties when passed to list_move(). Therefore list_move()
is only called if it is actually guaranteed that an element was found
within the list iteration.
Link: https://lore.kernel.org/all/[email protected]/
Signed-off-by: Jakob Koschel <[email protected]>
---
drivers/nvdimm/namespace_devs.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/nvdimm/namespace_devs.c b/drivers/nvdimm/namespace_devs.c
index b57a2d36c517..b2841e723bc3 100644
--- a/drivers/nvdimm/namespace_devs.c
+++ b/drivers/nvdimm/namespace_devs.c
@@ -1894,15 +1894,17 @@ static int select_pmem_id(struct nd_region *nd_region, const uuid_t *pmem_id)
struct nvdimm_drvdata *ndd = to_ndd(nd_mapping);
struct nd_namespace_label *nd_label = NULL;
u64 hw_start, hw_end, pmem_start, pmem_end;
- struct nd_label_ent *label_ent;
+ struct nd_label_ent *label_ent = NULL, *iter;
lockdep_assert_held(&nd_mapping->lock);
- list_for_each_entry(label_ent, &nd_mapping->labels, list) {
- nd_label = label_ent->label;
+ list_for_each_entry(iter, &nd_mapping->labels, list) {
+ nd_label = iter->label;
if (!nd_label)
continue;
- if (nsl_uuid_equal(ndd, nd_label, pmem_id))
+ if (nsl_uuid_equal(ndd, nd_label, pmem_id)) {
+ label_ent = iter;
break;
+ }
nd_label = NULL;
}
@@ -1930,7 +1932,8 @@ static int select_pmem_id(struct nd_region *nd_region, const uuid_t *pmem_id)
}
/* move recently validated label to the front of the list */
- list_move(&label_ent->list, &nd_mapping->labels);
+ if (label_ent)
+ list_move(&label_ent->list, &nd_mapping->labels);
}
return 0;
}
base-commit: 34e047aa16c0123bbae8e2f6df33e5ecc1f56601
--
2.25.1