Merge tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache

Pull folio updates from Matthew Wilcox:

 - Rewrite how munlock works to massively reduce the contention on
   i_mmap_rwsem (Hugh Dickins):

     https://lore.kernel.org/linux-mm/8e4356d-9622-a7f0-b2c-f116b5f2efea@google.com/

 - Sort out the page refcount mess for ZONE_DEVICE pages (Christoph
   Hellwig):

     https://lore.kernel.org/linux-mm/20220210072828.2930359-1-hch@lst.de/

 - Convert GUP to use folios and make pincount available for order-1
   pages. (Matthew Wilcox)

 - Convert a few more truncation functions to use folios (Matthew
   Wilcox)

 - Convert page_vma_mapped_walk to use PFNs instead of pages (Matthew
   Wilcox)

 - Convert rmap_walk to use folios (Matthew Wilcox)

 - Convert most of shrink_page_list() to use a folio (Matthew Wilcox)

 - Add support for creating large folios in readahead (Matthew Wilcox)

* tag 'folio-5.18c' of git://git.infradead.org/users/willy/pagecache: (114 commits)
  mm/damon: minor cleanup for damon_pa_young
  selftests/vm/transhuge-stress: Support file-backed PMD folios
  mm/filemap: Support VM_HUGEPAGE for file mappings
  mm/readahead: Switch to page_cache_ra_order
  mm/readahead: Align file mappings for non-DAX
  mm/readahead: Add large folio readahead
  mm: Support arbitrary THP sizes
  mm: Make large folios depend on THP
  mm: Fix READ_ONLY_THP warning
  mm/filemap: Allow large folios to be added to the page cache
  mm: Turn can_split_huge_page() into can_split_folio()
  mm/vmscan: Convert pageout() to take a folio
  mm/vmscan: Turn page_check_references() into folio_check_references()
  mm/vmscan: Account large folios correctly
  mm/vmscan: Optimise shrink_page_list for non-PMD-sized folios
  mm/vmscan: Free non-shmem folios without splitting them
  mm/rmap: Constify the rmap_walk_control argument
  mm/rmap: Convert rmap_walk() to take a folio
  mm: Turn page_anon_vma() into folio_anon_vma()
  mm/rmap: Turn page_lock_anon_vma_read() into folio_lock_anon_vma_read()
  ...

1 files changed, 34 insertions, 2 deletions

diff --git a/mm/util.c b/mm/util.c
index d3102081add0..1e2728736398 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -681,9 +681,8 @@ bool folio_mapped(struct folio *folio)
 }
 EXPORT_SYMBOL(folio_mapped);
 
-struct anon_vma *page_anon_vma(struct page *page)
+struct anon_vma *folio_anon_vma(struct folio *folio)
 {
-	struct folio *folio = page_folio(page);
 	unsigned long mapping = (unsigned long)folio->mapping;
 
 	if ((mapping & PAGE_MAPPING_FLAGS) != PAGE_MAPPING_ANON)
@@ -743,6 +742,39 @@ int __page_mapcount(struct page *page)
 EXPORT_SYMBOL_GPL(__page_mapcount);
 
 /**
+ * folio_mapcount() - Calculate the number of mappings of this folio.
+ * @folio: The folio.
+ *
+ * A large folio tracks both how many times the entire folio is mapped,
+ * and how many times each individual page in the folio is mapped.
+ * This function calculates the total number of times the folio is
+ * mapped.
+ *
+ * Return: The number of times this folio is mapped.
+ */
+int folio_mapcount(struct folio *folio)
+{
+	int i, compound, nr, ret;
+
+	if (likely(!folio_test_large(folio)))
+		return atomic_read(&folio->_mapcount) + 1;
+
+	compound = folio_entire_mapcount(folio);
+	nr = folio_nr_pages(folio);
+	if (folio_test_hugetlb(folio))
+		return compound;
+	ret = compound;
+	for (i = 0; i < nr; i++)
+		ret += atomic_read(&folio_page(folio, i)->_mapcount) + 1;
+	/* File pages has compound_mapcount included in _mapcount */
+	if (!folio_test_anon(folio))
+		return ret - compound * nr;
+	if (folio_test_double_map(folio))
+		ret -= nr;
+	return ret;
+}
+
+/**
  * folio_copy - Copy the contents of one folio to another.
  * @dst: Folio to copy to.
  * @src: Folio to copy from.