1 files changed, 67 insertions, 6 deletions

diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 977c641f78cf..5fb427aed612 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -557,9 +557,10 @@ static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
 			       unsigned long addr, unsigned long end,
 			       struct mm_walk *walk)
 {
+	int ret = 0;
 #ifdef CONFIG_HUGETLB_PAGE
 	struct queue_pages *qp = walk->private;
-	unsigned long flags = qp->flags;
+	unsigned long flags = (qp->flags & MPOL_MF_VALID);
 	struct page *page;
 	spinlock_t *ptl;
 	pte_t entry;
@@ -571,16 +572,44 @@ static int queue_pages_hugetlb(pte_t *pte, unsigned long hmask,
 	page = pte_page(entry);
 	if (!queue_pages_required(page, qp))
 		goto unlock;
+
+	if (flags == MPOL_MF_STRICT) {
+		/*
+		 * STRICT alone means only detecting misplaced page and no
+		 * need to further check other vma.
+		 */
+		ret = -EIO;
+		goto unlock;
+	}
+
+	if (!vma_migratable(walk->vma)) {
+		/*
+		 * Must be STRICT with MOVE*, otherwise .test_walk() have
+		 * stopped walking current vma.
+		 * Detecting misplaced page but allow migrating pages which
+		 * have been queued.
+		 */
+		ret = 1;
+		goto unlock;
+	}
+
 	/* With MPOL_MF_MOVE, we migrate only unshared hugepage. */
 	if (flags & (MPOL_MF_MOVE_ALL) ||
-	    (flags & MPOL_MF_MOVE && page_mapcount(page) == 1))
-		isolate_huge_page(page, qp->pagelist);
+	    (flags & MPOL_MF_MOVE && page_mapcount(page) == 1)) {
+		if (!isolate_huge_page(page, qp->pagelist) &&
+			(flags & MPOL_MF_STRICT))
+			/*
+			 * Failed to isolate page but allow migrating pages
+			 * which have been queued.
+			 */
+			ret = 1;
+	}
 unlock:
 	spin_unlock(ptl);
 #else
 	BUG();
 #endif
-	return 0;
+	return ret;
 }
 
 #ifdef CONFIG_NUMA_BALANCING
@@ -621,7 +650,7 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end,
 	unsigned long flags = qp->flags;
 
 	/* range check first */
-	VM_BUG_ON((vma->vm_start > start) || (vma->vm_end < end));
+	VM_BUG_ON_VMA((vma->vm_start > start) || (vma->vm_end < end), vma);
 
 	if (!qp->first) {
 		qp->first = vma;
@@ -1714,6 +1743,34 @@ COMPAT_SYSCALL_DEFINE4(migrate_pages, compat_pid_t, pid,
 
 #endif /* CONFIG_COMPAT */
 
+bool vma_migratable(struct vm_area_struct *vma)
+{
+	if (vma->vm_flags & (VM_IO | VM_PFNMAP))
+		return false;
+
+	/*
+	 * DAX device mappings require predictable access latency, so avoid
+	 * incurring periodic faults.
+	 */
+	if (vma_is_dax(vma))
+		return false;
+
+	if (is_vm_hugetlb_page(vma) &&
+		!hugepage_migration_supported(hstate_vma(vma)))
+		return false;
+
+	/*
+	 * Migration allocates pages in the highest zone. If we cannot
+	 * do so then migration (at least from node to node) is not
+	 * possible.
+	 */
+	if (vma->vm_file &&
+		gfp_zone(mapping_gfp_mask(vma->vm_file->f_mapping))
+			< policy_zone)
+		return false;
+	return true;
+}
+
 struct mempolicy *__get_vma_policy(struct vm_area_struct *vma,
 						unsigned long addr)
 {
@@ -2841,7 +2898,9 @@ int mpol_parse_str(char *str, struct mempolicy **mpol)
 	switch (mode) {
 	case MPOL_PREFERRED:
 		/*
-		 * Insist on a nodelist of one node only
+		 * Insist on a nodelist of one node only, although later
+		 * we use first_node(nodes) to grab a single node, so here
+		 * nodelist (or nodes) cannot be empty.
 		 */
 		if (nodelist) {
 			char *rest = nodelist;
@@ -2849,6 +2908,8 @@ int mpol_parse_str(char *str, struct mempolicy **mpol)
 				rest++;
 			if (*rest)
 				goto out;
+			if (nodes_empty(nodes))
+				goto out;
 		}
 		break;
 	case MPOL_INTERLEAVE: