From: Yang Shi shy828301@gmail.com Subject: mm: hwpoison: remove the unnecessary THP check

When handling THP hwpoison checked if the THP is in allocation or free stage since hwpoison may mistreat it as hugetlb page. After commit 415c64c1453a ("mm/memory-failure: split thp earlier in memory error handling") the problem has been fixed, so this check is no longer needed. Remove it. The side effect of the removal is hwpoison may report unsplit THP instead of unknown error for shmem THP. It seems not like a big deal.

The following patch "mm: filemap: check if THP has hwpoisoned subpage for PMD page fault" depends on this, which fixes shmem THP with hwpoisoned subpage(s) are mapped PMD wrongly. So this patch needs to be backported to -stable as well.

Link: https://lkml.kernel.org/r/20211020210755.23964-2-shy828301@gmail.com Signed-off-by: Yang Shi shy828301@gmail.com Suggested-by: Naoya Horiguchi naoya.horiguchi@nec.com Acked-by: Naoya Horiguchi naoya.horiguchi@nec.com Cc: Hugh Dickins hughd@google.com Cc: Kirill A. Shutemov kirill.shutemov@linux.intel.com Cc: Matthew Wilcox willy@infradead.org Cc: Oscar Salvador osalvador@suse.de Cc: Peter Xu peterx@redhat.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

mm/memory-failure.c | 14 -------------- 1 file changed, 14 deletions(-)

--- a/mm/memory-failure.c~mm-hwpoison-remove-the-unnecessary-thp-check +++ a/mm/memory-failure.c @@ -1147,20 +1147,6 @@ static int __get_hwpoison_page(struct pa if (!HWPoisonHandlable(head)) return -EBUSY;

- if (PageTransHuge(head)) { - /* - * Non anonymous thp exists only in allocation/free time. We - * can't handle such a case correctly, so let's give it up. - * This should be better than triggering BUG_ON when kernel - * tries to touch the "partially handled" page. - */ - if (!PageAnon(head)) { - pr_err("Memory failure: %#lx: non anonymous thp\n", - page_to_pfn(page)); - return 0; - } - } - if (get_page_unless_zero(head)) { if (head == compound_head(page)) return 1; _