Merge tag 'v4.20-rc5' into for-4.21/block

Pull in v4.20-rc5, solving a conflict we'll otherwise get in aio.c and
also getting the merge fix that went into mainline that users are
hitting testing for-4.21/block and/or for-next.

* tag 'v4.20-rc5': (664 commits)
  Linux 4.20-rc5
  PCI: Fix incorrect value returned from pcie_get_speed_cap()
  MAINTAINERS: Update linux-mips mailing list address
  ocfs2: fix potential use after free
  mm/khugepaged: fix the xas_create_range() error path
  mm/khugepaged: collapse_shmem() do not crash on Compound
  mm/khugepaged: collapse_shmem() without freezing new_page
  mm/khugepaged: minor reorderings in collapse_shmem()
  mm/khugepaged: collapse_shmem() remember to clear holes
  mm/khugepaged: fix crashes due to misaccounted holes
  mm/khugepaged: collapse_shmem() stop if punched or truncated
  mm/huge_memory: fix lockdep complaint on 32-bit i_size_read()
  mm/huge_memory: splitting set mapping+index before unfreeze
  mm/huge_memory: rename freeze_page() to unmap_page()
  initramfs: clean old path before creating a hardlink
  kernel/kcov.c: mark funcs in __sanitizer_cov_trace_pc() as notrace
  psi: make disabling/enabling easier for vendor kernels
  proc: fixup map_files test on arm
  debugobjects: avoid recursive calls with kmemleak
  userfaultfd: shmem: UFFDIO_COPY: set the page dirty if VM_WRITE is not set
  ...

1 files changed, 37 insertions, 6 deletions

diff --git a/mm/shmem.c b/mm/shmem.c
index d44991ea5ed4..cddc72ac44d8 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -297,12 +297,14 @@ bool shmem_charge(struct inode *inode, long pages)
 	if (!shmem_inode_acct_block(inode, pages))
 		return false;
 
+	/* nrpages adjustment first, then shmem_recalc_inode() when balanced */
+	inode->i_mapping->nrpages += pages;
+
 	spin_lock_irqsave(&info->lock, flags);
 	info->alloced += pages;
 	inode->i_blocks += pages * BLOCKS_PER_PAGE;
 	shmem_recalc_inode(inode);
 	spin_unlock_irqrestore(&info->lock, flags);
-	inode->i_mapping->nrpages += pages;
 
 	return true;
 }
@@ -312,6 +314,8 @@ void shmem_uncharge(struct inode *inode, long pages)
 	struct shmem_inode_info *info = SHMEM_I(inode);
 	unsigned long flags;
 
+	/* nrpages adjustment done by __delete_from_page_cache() or caller */
+
 	spin_lock_irqsave(&info->lock, flags);
 	info->alloced -= pages;
 	inode->i_blocks -= pages * BLOCKS_PER_PAGE;
@@ -1509,11 +1513,13 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
 {
 	struct page *oldpage, *newpage;
 	struct address_space *swap_mapping;
+	swp_entry_t entry;
 	pgoff_t swap_index;
 	int error;
 
 	oldpage = *pagep;
-	swap_index = page_private(oldpage);
+	entry.val = page_private(oldpage);
+	swap_index = swp_offset(entry);
 	swap_mapping = page_mapping(oldpage);
 
 	/*
@@ -1532,7 +1538,7 @@ static int shmem_replace_page(struct page **pagep, gfp_t gfp,
 	__SetPageLocked(newpage);
 	__SetPageSwapBacked(newpage);
 	SetPageUptodate(newpage);
-	set_page_private(newpage, swap_index);
+	set_page_private(newpage, entry.val);
 	SetPageSwapCache(newpage);
 
 	/*
@@ -2214,6 +2220,7 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
 	struct page *page;
 	pte_t _dst_pte, *dst_pte;
 	int ret;
+	pgoff_t offset, max_off;
 
 	ret = -ENOMEM;
 	if (!shmem_inode_acct_block(inode, 1))
@@ -2236,7 +2243,7 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
 				*pagep = page;
 				shmem_inode_unacct_blocks(inode, 1);
 				/* don't free the page */
-				return -EFAULT;
+				return -ENOENT;
 			}
 		} else {		/* mfill_zeropage_atomic */
 			clear_highpage(page);
@@ -2251,6 +2258,12 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
 	__SetPageSwapBacked(page);
 	__SetPageUptodate(page);
 
+	ret = -EFAULT;
+	offset = linear_page_index(dst_vma, dst_addr);
+	max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
+	if (unlikely(offset >= max_off))
+		goto out_release;
+
 	ret = mem_cgroup_try_charge_delay(page, dst_mm, gfp, &memcg, false);
 	if (ret)
 		goto out_release;
@@ -2265,9 +2278,25 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
 	_dst_pte = mk_pte(page, dst_vma->vm_page_prot);
 	if (dst_vma->vm_flags & VM_WRITE)
 		_dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte));
+	else {
+		/*
+		 * We don't set the pte dirty if the vma has no
+		 * VM_WRITE permission, so mark the page dirty or it
+		 * could be freed from under us. We could do it
+		 * unconditionally before unlock_page(), but doing it
+		 * only if VM_WRITE is not set is faster.
+		 */
+		set_page_dirty(page);
+	}
 
-	ret = -EEXIST;
 	dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
+
+	ret = -EFAULT;
+	max_off = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE);
+	if (unlikely(offset >= max_off))
+		goto out_release_uncharge_unlock;
+
+	ret = -EEXIST;
 	if (!pte_none(*dst_pte))
 		goto out_release_uncharge_unlock;
 
@@ -2285,13 +2314,15 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
 
 	/* No need to invalidate - it was non-present before */
 	update_mmu_cache(dst_vma, dst_addr, dst_pte);
-	unlock_page(page);
 	pte_unmap_unlock(dst_pte, ptl);
+	unlock_page(page);
 	ret = 0;
 out:
 	return ret;
 out_release_uncharge_unlock:
 	pte_unmap_unlock(dst_pte, ptl);
+	ClearPageDirty(page);
+	delete_from_page_cache(page);
 out_release_uncharge:
 	mem_cgroup_cancel_charge(page, memcg, false);
 out_release: