Merge tag 'mm-hotfixes-stable-2023-06-12-12-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull misc fixes from Andrew Morton:
 "19 hotfixes. 14 are cc:stable and the remainder address issues which
  were introduced during this development cycle or which were considered
  inappropriate for a backport"

* tag 'mm-hotfixes-stable-2023-06-12-12-22' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
  zswap: do not shrink if cgroup may not zswap
  page cache: fix page_cache_next/prev_miss off by one
  ocfs2: check new file size on fallocate call
  mailmap: add entry for John Keeping
  mm/damon/core: fix divide error in damon_nr_accesses_to_accesses_bp()
  epoll: ep_autoremove_wake_function should use list_del_init_careful
  mm/gup_test: fix ioctl fail for compat task
  nilfs2: reject devices with insufficient block count
  ocfs2: fix use-after-free when unmounting read-only filesystem
  lib/test_vmalloc.c: avoid garbage in page array
  nilfs2: fix possible out-of-bounds segment allocation in resize ioctl
  riscv/purgatory: remove PGO flags
  powerpc/purgatory: remove PGO flags
  x86/purgatory: remove PGO flags
  kexec: support purgatories with .text.hot sections
  mm/uffd: allow vma to merge as much as possible
  mm/uffd: fix vma operation where start addr cuts part of vma
  radix-tree: move declarations to header
  nilfs2: fix incomplete buffer cleanup in nilfs_btnode_abort_change_key()

1 files changed, 16 insertions, 10 deletions

diff --git a/mm/filemap.c b/mm/filemap.c
index b4c9bd368b7e..83dda76d1fc3 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1760,7 +1760,9 @@ bool __folio_lock_or_retry(struct folio *folio, struct mm_struct *mm,
  *
  * Return: The index of the gap if found, otherwise an index outside the
  * range specified (in which case 'return - index >= max_scan' will be true).
- * In the rare case of index wrap-around, 0 will be returned.
+ * In the rare case of index wrap-around, 0 will be returned.  0 will also
+ * be returned if index == 0 and there is a gap at the index.  We can not
+ * wrap-around if passed index == 0.
  */
 pgoff_t page_cache_next_miss(struct address_space *mapping,
 			     pgoff_t index, unsigned long max_scan)
@@ -1770,12 +1772,13 @@ pgoff_t page_cache_next_miss(struct address_space *mapping,
 	while (max_scan--) {
 		void *entry = xas_next(&xas);
 		if (!entry || xa_is_value(entry))
-			break;
-		if (xas.xa_index == 0)
-			break;
+			return xas.xa_index;
+		if (xas.xa_index == 0 && index != 0)
+			return xas.xa_index;
 	}
 
-	return xas.xa_index;
+	/* No gaps in range and no wrap-around, return index beyond range */
+	return xas.xa_index + 1;
 }
 EXPORT_SYMBOL(page_cache_next_miss);
 
@@ -1796,7 +1799,9 @@ EXPORT_SYMBOL(page_cache_next_miss);
  *
  * Return: The index of the gap if found, otherwise an index outside the
  * range specified (in which case 'index - return >= max_scan' will be true).
- * In the rare case of wrap-around, ULONG_MAX will be returned.
+ * In the rare case of wrap-around, ULONG_MAX will be returned.  ULONG_MAX
+ * will also be returned if index == ULONG_MAX and there is a gap at the
+ * index.  We can not wrap-around if passed index == ULONG_MAX.
  */
 pgoff_t page_cache_prev_miss(struct address_space *mapping,
 			     pgoff_t index, unsigned long max_scan)
@@ -1806,12 +1811,13 @@ pgoff_t page_cache_prev_miss(struct address_space *mapping,
 	while (max_scan--) {
 		void *entry = xas_prev(&xas);
 		if (!entry || xa_is_value(entry))
-			break;
-		if (xas.xa_index == ULONG_MAX)
-			break;
+			return xas.xa_index;
+		if (xas.xa_index == ULONG_MAX && index != ULONG_MAX)
+			return xas.xa_index;
 	}
 
-	return xas.xa_index;
+	/* No gaps in range and no wrap-around, return index beyond range */
+	return xas.xa_index - 1;
 }
 EXPORT_SYMBOL(page_cache_prev_miss);