fs: use nth_page() in place of direct struct page manipulation

When dealing with hugetlb pages, struct page is not guaranteed to be
contiguous on SPARSEMEM without VMEMMAP.  Use nth_page() to handle it
properly.

Without the fix, a wrong subpage might be checked for HWPoison, causing wrong
number of bytes of a page copied to user space. No bug is reported. The fix
comes from code inspection.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 38c1ddbde6c6 ("hugetlbfs: improve read HWPOISON hugepage")
Signed-off-by: Zi Yan <[email protected]>
Reviewed-by: Muchun Song <[email protected]>
Cc: David Hildenbrand <[email protected]>
Cc: Matthew Wilcox (Oracle) <[email protected]>
Cc: Mike Kravetz <[email protected]>
Cc: Mike Rapoport (IBM) <[email protected]>
Cc: Thomas Bogendoerfer <[email protected]>
Cc: <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions