[PATCH 02/10] mm/hugetlb: make sure to get NULL when list is empty

[Wei Yang]

list_first_entry() may not return NULL even when the list is empty.

Let's make sure the behavior by using list_first_entry_or_null(),
otherwise it would corrupt the list.

Signed-off-by: Wei Yang <richard.weiyang@xxxxxxxxxxxxxxxxx>
---
 mm/hugetlb.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 62ec74f6d03f..0a2f3851b828 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -237,7 +237,8 @@ get_file_region_entry_from_cache(struct resv_map *resv, long from, long to)
 	VM_BUG_ON(resv->region_cache_count <= 0);
 
 	resv->region_cache_count--;
-	nrg = list_first_entry(&resv->region_cache, struct file_region, link);
+	nrg = list_first_entry_or_null(&resv->region_cache,
+			struct file_region, link);
 	VM_BUG_ON(!nrg);
 	list_del(&nrg->link);
 
-- 
2.20.1 (Apple Git-117)