Merge branch 'akpm' (patches from Andrew)

Merge updates from Andrew Morton:
 "Incoming:

   - a small number of updates to scripts/, ocfs2 and fs/buffer.c

   - most of MM

  I still have quite a lot of material (mostly not MM) staged after
  linux-next due to -next dependencies. I'll send those across next week
  as the preprequisites get merged up"

* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (135 commits)
  mm/page_io.c: annotate refault stalls from swap_readpage
  mm/Kconfig: fix trivial help text punctuation
  mm/Kconfig: fix indentation
  mm/memory_hotplug.c: remove __online_page_set_limits()
  mm: fix typos in comments when calling __SetPageUptodate()
  mm: fix struct member name in function comments
  mm/shmem.c: cast the type of unmap_start to u64
  mm: shmem: use proper gfp flags for shmem_writepage()
  mm/shmem.c: make array 'values' static const, makes object smaller
  userfaultfd: require CAP_SYS_PTRACE for UFFD_FEATURE_EVENT_FORK
  fs/userfaultfd.c: wp: clear VM_UFFD_MISSING or VM_UFFD_WP during userfaultfd_register()
  userfaultfd: wrap the common dst_vma check into an inlined function
  userfaultfd: remove unnecessary WARN_ON() in __mcopy_atomic_hugetlb()
  userfaultfd: use vma_pagesize for all huge page size calculation
  mm/madvise.c: use PAGE_ALIGN[ED] for range checking
  mm/madvise.c: replace with page_size() in madvise_inject_error()
  mm/mmap.c: make vma_merge() comment more easy to understand
  mm/hwpoison-inject: use DEFINE_DEBUGFS_ATTRIBUTE to define debugfs fops
  autonuma: reduce cache footprint when scanning page tables
  autonuma: fix watermark checking in migrate_balanced_pgdat()
  ...

1 files changed, 17 insertions, 12 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index 220be9fa2c41..165fa6332993 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -1369,7 +1369,8 @@ static int shmem_writepage(struct page *page, struct writeback_control *wbc)
 	if (list_empty(&info->swaplist))
 		list_add(&info->swaplist, &shmem_swaplist);
 
-	if (add_to_swap_cache(page, swap, GFP_ATOMIC) == 0) {
+	if (add_to_swap_cache(page, swap,
+			__GFP_HIGH | __GFP_NOMEMALLOC | __GFP_NOWARN) == 0) {
 		spin_lock_irq(&info->lock);
 		shmem_recalc_inode(inode);
 		info->swapped++;
@@ -2022,16 +2023,14 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf)
 		    shmem_falloc->waitq &&
 		    vmf->pgoff >= shmem_falloc->start &&
 		    vmf->pgoff < shmem_falloc->next) {
+			struct file *fpin;
 			wait_queue_head_t *shmem_falloc_waitq;
 			DEFINE_WAIT_FUNC(shmem_fault_wait, synchronous_wake_function);
 
 			ret = VM_FAULT_NOPAGE;
-			if ((vmf->flags & FAULT_FLAG_ALLOW_RETRY) &&
-			   !(vmf->flags & FAULT_FLAG_RETRY_NOWAIT)) {
-				/* It's polite to up mmap_sem if we can */
-				up_read(&vma->vm_mm->mmap_sem);
+			fpin = maybe_unlock_mmap_for_io(vmf, NULL);
+			if (fpin)
 				ret = VM_FAULT_RETRY;
-			}
 
 			shmem_falloc_waitq = shmem_falloc->waitq;
 			prepare_to_wait(shmem_falloc_waitq, &shmem_fault_wait,
@@ -2049,6 +2048,9 @@ static vm_fault_t shmem_fault(struct vm_fault *vmf)
 			spin_lock(&inode->i_lock);
 			finish_wait(shmem_falloc_waitq, &shmem_fault_wait);
 			spin_unlock(&inode->i_lock);
+
+			if (fpin)
+				fput(fpin);
 			return ret;
 		}
 		spin_unlock(&inode->i_lock);
@@ -2213,11 +2215,14 @@ static int shmem_mmap(struct file *file, struct vm_area_struct *vma)
 			return -EPERM;
 
 		/*
-		 * Since the F_SEAL_FUTURE_WRITE seals allow for a MAP_SHARED
-		 * read-only mapping, take care to not allow mprotect to revert
-		 * protections.
+		 * Since an F_SEAL_FUTURE_WRITE sealed memfd can be mapped as
+		 * MAP_SHARED and read-only, take care to not allow mprotect to
+		 * revert protections on such mappings. Do this only for shared
+		 * mappings. For private mappings, don't need to mask
+		 * VM_MAYWRITE as we still want them to be COW-writable.
 		 */
-		vma->vm_flags &= ~(VM_MAYWRITE);
+		if (vma->vm_flags & VM_SHARED)
+			vma->vm_flags &= ~(VM_MAYWRITE);
 	}
 
 	file_accessed(file);
@@ -2742,7 +2747,7 @@ static long shmem_fallocate(struct file *file, int mode, loff_t offset,
 		}
 
 		shmem_falloc.waitq = &shmem_falloc_waitq;
-		shmem_falloc.start = unmap_start >> PAGE_SHIFT;
+		shmem_falloc.start = (u64)unmap_start >> PAGE_SHIFT;
 		shmem_falloc.next = (unmap_end + 1) >> PAGE_SHIFT;
 		spin_lock(&inode->i_lock);
 		inode->i_private = &shmem_falloc;
@@ -3928,7 +3933,7 @@ out2:
 static ssize_t shmem_enabled_show(struct kobject *kobj,
 		struct kobj_attribute *attr, char *buf)
 {
-	int values[] = {
+	static const int values[] = {
 		SHMEM_HUGE_ALWAYS,
 		SHMEM_HUGE_WITHIN_SIZE,
 		SHMEM_HUGE_ADVISE,