Merge tag 'mm-hotfixes-stable-2023-02-17-15-16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "Six hotfixes. Five are cc:stable: four for MM, one for nilfs2.

  Also a MAINTAINERS update"

* tag 'mm-hotfixes-stable-2023-02-17-15-16-2' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  nilfs2: fix underflow in second superblock position calculations
  hugetlb: check for undefined shift on 32 bit architectures
  mm/migrate: fix wrongly apply write bit after mkdirty on sparc64
  MAINTAINERS: update FPU EMULATOR web page
  mm/MADV_COLLAPSE: set EAGAIN on unexpected page refcount
  mm/filemap: fix page end in filemap_get_read_batch

4 files changed, 10 insertions, 4 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index c4d4ace9cc70..0e20a8d6dd93 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -2588,18 +2588,19 @@ static int filemap_get_pages(struct kiocb *iocb, struct iov_iter *iter,
 	struct folio *folio;
 	int err = 0;
 
+	/* "last_index" is the index of the page beyond the end of the read */
 	last_index = DIV_ROUND_UP(iocb->ki_pos + iter->count, PAGE_SIZE);
 retry:
 	if (fatal_signal_pending(current))
 		return -EINTR;
 
-	filemap_get_read_batch(mapping, index, last_index, fbatch);
+	filemap_get_read_batch(mapping, index, last_index - 1, fbatch);
 	if (!folio_batch_count(fbatch)) {
 		if (iocb->ki_flags & IOCB_NOIO)
 			return -EAGAIN;
 		page_cache_sync_readahead(mapping, ra, filp, index,
 				last_index - index);
-		filemap_get_read_batch(mapping, index, last_index, fbatch);
+		filemap_get_read_batch(mapping, index, last_index - 1, fbatch);
 	}
 	if (!folio_batch_count(fbatch)) {
 		if (iocb->ki_flags & (IOCB_NOWAIT | IOCB_WAITQ))
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index abe6cfd92ffa..1b791b26d72d 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3272,8 +3272,6 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)
 	pmde = mk_huge_pmd(new, READ_ONCE(vma->vm_page_prot));
 	if (pmd_swp_soft_dirty(*pvmw->pmd))
 		pmde = pmd_mksoft_dirty(pmde);
-	if (is_writable_migration_entry(entry))
-		pmde = maybe_pmd_mkwrite(pmde, vma);
 	if (pmd_swp_uffd_wp(*pvmw->pmd))
 		pmde = pmd_wrprotect(pmd_mkuffd_wp(pmde));
 	if (!is_migration_entry_young(entry))
@@ -3281,6 +3279,10 @@ void remove_migration_pmd(struct page_vma_mapped_walk *pvmw, struct page *new)
 	/* NOTE: this may contain setting soft-dirty on some archs */
 	if (PageDirty(new) && is_migration_entry_dirty(entry))
 		pmde = pmd_mkdirty(pmde);
+	if (is_writable_migration_entry(entry))
+		pmde = maybe_pmd_mkwrite(pmde, vma);
+	else
+		pmde = pmd_wrprotect(pmde);
 
 	if (PageAnon(new)) {
 		rmap_t rmap_flags = RMAP_COMPOUND;
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index 90acfea40c13..a26a28e3738c 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -2611,6 +2611,7 @@ static int madvise_collapse_errno(enum scan_result r)
 	case SCAN_CGROUP_CHARGE_FAIL:
 		return -EBUSY;
 	/* Resource temporary unavailable - trying again might succeed */
+	case SCAN_PAGE_COUNT:
 	case SCAN_PAGE_LOCK:
 	case SCAN_PAGE_LRU:
 	case SCAN_DEL_PAGE_LRU:
diff --git a/mm/migrate.c b/mm/migrate.c
index a4d3fc65085f..cc5455614e01 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -224,6 +224,8 @@ static bool remove_migration_pte(struct folio *folio,
 			pte = maybe_mkwrite(pte, vma);
 		else if (pte_swp_uffd_wp(*pvmw.pte))
 			pte = pte_mkuffd_wp(pte);
+		else
+			pte = pte_wrprotect(pte);
 
 		if (folio_test_anon(folio) && !is_readable_migration_entry(entry))
 			rmap_flags |= RMAP_EXCLUSIVE;