Merge branch 'akpm' (patches from Andrew)

Merge more updates from Andrew Morton:

 - most of the rest of MM

 - a small number of misc things

 - lib/ updates

 - checkpatch

 - autofs updates

 - ipc/ updates

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (126 commits)
  ipc: optimize semget/shmget/msgget for lots of keys
  ipc/sem: play nicer with large nsops allocations
  ipc/sem: drop sem_checkid helper
  ipc: convert kern_ipc_perm.refcount from atomic_t to refcount_t
  ipc: convert sem_undo_list.refcnt from atomic_t to refcount_t
  ipc: convert ipc_namespace.count from atomic_t to refcount_t
  kcov: support compat processes
  sh: defconfig: cleanup from old Kconfig options
  mn10300: defconfig: cleanup from old Kconfig options
  m32r: defconfig: cleanup from old Kconfig options
  drivers/pps: use surrounding "if PPS" to remove numerous dependency checks
  drivers/pps: aesthetic tweaks to PPS-related content
  cpumask: make cpumask_next() out-of-line
  kmod: move #ifdef CONFIG_MODULES wrapper to Makefile
  kmod: split off umh headers into its own file
  MAINTAINERS: clarify kmod is just a kernel module loader
  kmod: split out umh code into its own file
  test_kmod: flip INT checks to be consistent
  test_kmod: remove paranoid UINT_MAX check on uint range processing
  vfat: deduplicate hex2bin()
  ...

1 files changed, 27 insertions, 2 deletions

diff --git a/mm/gup.c b/mm/gup.c
index 33d651deeae2..b2b4d4263768 100644
--- a/mm/gup.c
+++ b/mm/gup.c
@@ -234,6 +234,16 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
 			return page;
 		return no_page_table(vma, flags);
 	}
+retry:
+	if (!pmd_present(*pmd)) {
+		if (likely(!(flags & FOLL_MIGRATION)))
+			return no_page_table(vma, flags);
+		VM_BUG_ON(thp_migration_supported() &&
+				  !is_pmd_migration_entry(*pmd));
+		if (is_pmd_migration_entry(*pmd))
+			pmd_migration_entry_wait(mm, pmd);
+		goto retry;
+	}
 	if (pmd_devmap(*pmd)) {
 		ptl = pmd_lock(mm, pmd);
 		page = follow_devmap_pmd(vma, address, pmd, flags);
@@ -247,7 +257,15 @@ static struct page *follow_pmd_mask(struct vm_area_struct *vma,
 	if ((flags & FOLL_NUMA) && pmd_protnone(*pmd))
 		return no_page_table(vma, flags);
 
+retry_locked:
 	ptl = pmd_lock(mm, pmd);
+	if (unlikely(!pmd_present(*pmd))) {
+		spin_unlock(ptl);
+		if (likely(!(flags & FOLL_MIGRATION)))
+			return no_page_table(vma, flags);
+		pmd_migration_entry_wait(mm, pmd);
+		goto retry_locked;
+	}
 	if (unlikely(!pmd_trans_huge(*pmd))) {
 		spin_unlock(ptl);
 		return follow_page_pte(vma, address, pmd, flags);
@@ -424,7 +442,7 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address,
 	pud = pud_offset(p4d, address);
 	BUG_ON(pud_none(*pud));
 	pmd = pmd_offset(pud, address);
-	if (pmd_none(*pmd))
+	if (!pmd_present(*pmd))
 		return -EFAULT;
 	VM_BUG_ON(pmd_trans_huge(*pmd));
 	pte = pte_offset_map(pmd, address);
@@ -438,6 +456,13 @@ static int get_gate_page(struct mm_struct *mm, unsigned long address,
 		if ((gup_flags & FOLL_DUMP) || !is_zero_pfn(pte_pfn(*pte)))
 			goto unmap;
 		*page = pte_page(*pte);
+
+		/*
+		 * This should never happen (a device public page in the gate
+		 * area).
+		 */
+		if (is_device_public_page(*page))
+			goto unmap;
 	}
 	get_page(*page);
 out:
@@ -1534,7 +1559,7 @@ static int gup_pmd_range(pud_t pud, unsigned long addr, unsigned long end,
 		pmd_t pmd = READ_ONCE(*pmdp);
 
 		next = pmd_addr_end(addr, end);
-		if (pmd_none(pmd))
+		if (!pmd_present(pmd))
 			return 0;
 
 		if (unlikely(pmd_trans_huge(pmd) || pmd_huge(pmd))) {