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-rw-r--r--arch/s390/mm/gup.c8
1 files changed, 5 insertions, 3 deletions
diff --git a/arch/s390/mm/gup.c b/arch/s390/mm/gup.c
index 13dab0c16..3776aca22 100644
--- a/arch/s390/mm/gup.c
+++ b/arch/s390/mm/gup.c
@@ -20,9 +20,9 @@
static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
unsigned long end, int write, struct page **pages, int *nr)
{
+ struct page *head, *page;
unsigned long mask;
pte_t *ptep, pte;
- struct page *page;
mask = (write ? _PAGE_PROTECT : 0) | _PAGE_INVALID | _PAGE_SPECIAL;
@@ -37,12 +37,14 @@ static inline int gup_pte_range(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
return 0;
VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
page = pte_page(pte);
- if (!page_cache_get_speculative(page))
+ head = compound_head(page);
+ if (!page_cache_get_speculative(head))
return 0;
if (unlikely(pte_val(pte) != pte_val(*ptep))) {
- put_page(page);
+ put_page(head);
return 0;
}
+ VM_BUG_ON_PAGE(compound_head(page) != head, page);
pages[*nr] = page;
(*nr)++;