--- zzzz-none-000/linux-3.10.107/arch/s390/mm/gup.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/s390/mm/gup.c	2021-02-04 17:41:59.000000000 +0000
@@ -24,12 +24,15 @@
 	pte_t *ptep, pte;
 	struct page *page;
 
-	mask = (write ? _PAGE_RO : 0) | _PAGE_INVALID | _PAGE_SPECIAL;
+	mask = (write ? _PAGE_PROTECT : 0) | _PAGE_INVALID | _PAGE_SPECIAL;
 
 	ptep = ((pte_t *) pmd_deref(pmd)) + pte_index(addr);
 	do {
 		pte = *ptep;
 		barrier();
+		/* Similar to the PMD case, NUMA hinting must take slow path */
+		if (pte_protnone(pte))
+			return 0;
 		if ((pte_val(pte) & mask) != 0)
 			return 0;
 		VM_BUG_ON(!pfn_valid(pte_pfn(pte)));
@@ -55,8 +58,8 @@
 	struct page *head, *page, *tail;
 	int refs;
 
-	result = write ? 0 : _SEGMENT_ENTRY_RO;
-	mask = result | _SEGMENT_ENTRY_INV;
+	result = write ? 0 : _SEGMENT_ENTRY_PROTECT;
+	mask = result | _SEGMENT_ENTRY_INVALID;
 	if ((pmd_val(pmd) & mask) != result)
 		return 0;
 	VM_BUG_ON(!pfn_valid(pmd_val(pmd) >> PAGE_SHIFT));
@@ -106,11 +109,9 @@
 	pmd_t *pmdp, pmd;
 
 	pmdp = (pmd_t *) pudp;
-#ifdef CONFIG_64BIT
 	if ((pud_val(pud) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R3)
 		pmdp = (pmd_t *) pud_deref(pud);
 	pmdp += pmd_index(addr);
-#endif
 	do {
 		pmd = *pmdp;
 		barrier();
@@ -127,6 +128,13 @@
 		if (pmd_none(pmd) || pmd_trans_splitting(pmd))
 			return 0;
 		if (unlikely(pmd_large(pmd))) {
+			/*
+			 * NUMA hinting faults need to be handled in the GUP
+			 * slowpath for accounting purposes and so that they
+			 * can be serialised against THP migration.
+			 */
+			if (pmd_protnone(pmd))
+				return 0;
 			if (!gup_huge_pmd(pmdp, pmd, addr, next,
 					  write, pages, nr))
 				return 0;
@@ -145,11 +153,9 @@
 	pud_t *pudp, pud;
 
 	pudp = (pud_t *) pgdp;
-#ifdef CONFIG_64BIT
 	if ((pgd_val(pgd) & _REGION_ENTRY_TYPE_MASK) == _REGION_ENTRY_TYPE_R2)
 		pudp = (pud_t *) pgd_deref(pgd);
 	pudp += pud_index(addr);
-#endif
 	do {
 		pud = *pudp;
 		barrier();
@@ -180,9 +186,15 @@
 	addr = start;
 	len = (unsigned long) nr_pages << PAGE_SHIFT;
 	end = start + len;
-	if ((end < start) || (end > TASK_SIZE))
+	if ((end <= start) || (end > TASK_SIZE))
 		return 0;
-
+	/*
+	 * local_irq_save() doesn't prevent pagetable teardown, but does
+	 * prevent the pagetables from being freed on s390.
+	 *
+	 * So long as we atomically load page table pointers versus teardown,
+	 * we can follow the address down to the the page and take a ref on it.
+	 */
 	local_irq_save(flags);
 	pgdp = pgd_offset(mm, addr);
 	do {
@@ -219,63 +231,20 @@
 			struct page **pages)
 {
 	struct mm_struct *mm = current->mm;
-	unsigned long addr, len, end;
-	unsigned long next;
-	pgd_t *pgdp, pgd;
-	int nr = 0;
+	int nr, ret;
 
 	start &= PAGE_MASK;
-	addr = start;
-	len = (unsigned long) nr_pages << PAGE_SHIFT;
-	end = start + len;
-	if ((end < start) || (end > TASK_SIZE))
-		goto slow_irqon;
-
-	/*
-	 * local_irq_disable() doesn't prevent pagetable teardown, but does
-	 * prevent the pagetables from being freed on s390.
-	 *
-	 * So long as we atomically load page table pointers versus teardown,
-	 * we can follow the address down to the the page and take a ref on it.
-	 */
-	local_irq_disable();
-	pgdp = pgd_offset(mm, addr);
-	do {
-		pgd = *pgdp;
-		barrier();
-		next = pgd_addr_end(addr, end);
-		if (pgd_none(pgd))
-			goto slow;
-		if (!gup_pud_range(pgdp, pgd, addr, next, write, pages, &nr))
-			goto slow;
-	} while (pgdp++, addr = next, addr != end);
-	local_irq_enable();
-
-	VM_BUG_ON(nr != (end - start) >> PAGE_SHIFT);
-	return nr;
-
-	{
-		int ret;
-slow:
-		local_irq_enable();
-slow_irqon:
-		/* Try to get the remaining pages with get_user_pages */
-		start += nr << PAGE_SHIFT;
-		pages += nr;
-
-		down_read(&mm->mmap_sem);
-		ret = get_user_pages(current, mm, start,
-			(end - start) >> PAGE_SHIFT, write, 0, pages, NULL);
-		up_read(&mm->mmap_sem);
-
-		/* Have to be a bit careful with return values */
-		if (nr > 0) {
-			if (ret < 0)
-				ret = nr;
-			else
-				ret += nr;
-		}
-
-		return ret;
-	}
+	nr = __get_user_pages_fast(start, nr_pages, write, pages);
+	if (nr == nr_pages)
+		return nr;
+
+	/* Try to get the remaining pages with get_user_pages */
+	start += nr << PAGE_SHIFT;
+	pages += nr;
+	ret = get_user_pages_unlocked(current, mm, start,
+			     nr_pages - nr, write, 0, pages);
+	/* Have to be a bit careful with return values */
+	if (nr > 0)
+		ret = (ret < 0) ? nr : ret + nr;
+	return ret;
 }