Merge branch 'akpm' (patches from Andrew)

Merge misc fixes from Andrew Morton:
 "18 patches.

  Subsystems affected by this patch series: mm (memory-failure, swap,
  slub, hugetlb, memory-failure, slub, thp, sparsemem), and coredump"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>:
  mm/sparse: fix check_usemap_section_nr warnings
  mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split
  mm/thp: unmap_mapping_page() to fix THP truncate_cleanup_page()
  mm/thp: fix page_address_in_vma() on file THP tails
  mm/thp: fix vma_address() if virtual address below file offset
  mm/thp: try_to_unmap() use TTU_SYNC for safe splitting
  mm/thp: make is_huge_zero_pmd() safe and quicker
  mm/thp: fix __split_huge_pmd_locked() on shmem migration entry
  mm, thp: use head page in __migration_entry_wait()
  mm/slub.c: include swab.h
  crash_core, vmcoreinfo: append 'SECTION_SIZE_BITS' to vmcoreinfo
  mm/memory-failure: make sure wait for page writeback in memory_failure
  mm/hugetlb: expand restore_reserve_on_error functionality
  mm/slub: actually fix freelist pointer vs redzoning
  mm/slub: fix redzoning for small allocations
  mm/slub: clarify verification reporting
  mm/swap: fix pte_same_as_swp() not removing uffd-wp bit when compare
  mm,hwpoison: fix race with hugetlb page allocation

1 files changed, 17 insertions, 10 deletions

diff --git a/mm/page_vma_mapped.c b/mm/page_vma_mapped.c
index 2cf01d933f13..e37bd43904af 100644
--- a/mm/page_vma_mapped.c
+++ b/mm/page_vma_mapped.c
@@ -212,23 +212,34 @@ restart:
 			pvmw->ptl = NULL;
 		}
 	} else if (!pmd_present(pmde)) {
+		/*
+		 * If PVMW_SYNC, take and drop THP pmd lock so that we
+		 * cannot return prematurely, while zap_huge_pmd() has
+		 * cleared *pmd but not decremented compound_mapcount().
+		 */
+		if ((pvmw->flags & PVMW_SYNC) &&
+		    PageTransCompound(pvmw->page)) {
+			spinlock_t *ptl = pmd_lock(mm, pvmw->pmd);
+
+			spin_unlock(ptl);
+		}
 		return false;
 	}
 	if (!map_pte(pvmw))
 		goto next_pte;
 	while (1) {
+		unsigned long end;
+
 		if (check_pte(pvmw))
 			return true;
 next_pte:
 		/* Seek to next pte only makes sense for THP */
 		if (!PageTransHuge(pvmw->page) || PageHuge(pvmw->page))
 			return not_found(pvmw);
+		end = vma_address_end(pvmw->page, pvmw->vma);
 		do {
 			pvmw->address += PAGE_SIZE;
-			if (pvmw->address >= pvmw->vma->vm_end ||
-			    pvmw->address >=
-					__vma_address(pvmw->page, pvmw->vma) +
-					thp_size(pvmw->page))
+			if (pvmw->address >= end)
 				return not_found(pvmw);
 			/* Did we cross page table boundary? */
 			if (pvmw->address % PMD_SIZE == 0) {
@@ -266,14 +277,10 @@ int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma)
 		.vma = vma,
 		.flags = PVMW_SYNC,
 	};
-	unsigned long start, end;
-
-	start = __vma_address(page, vma);
-	end = start + thp_size(page) - PAGE_SIZE;
 
-	if (unlikely(end < vma->vm_start || start >= vma->vm_end))
+	pvmw.address = vma_address(page, vma);
+	if (pvmw.address == -EFAULT)
 		return 0;
-	pvmw.address = max(start, vma->vm_start);
 	if (!page_vma_mapped_walk(&pvmw))
 		return 0;
 	page_vma_mapped_walk_done(&pvmw);