mm/rmap: convert page_dup_file_rmap() to folio_dup_file_rmap_[pte|ptes|pmd]()

Let's convert page_dup_file_rmap() like the other rmap functions.  As
there is only a single caller, convert that single caller right away and
remove page_dup_file_rmap().

Add folio_dup_file_rmap_ptes() right away, we want to perform rmap baching
during fork() soon.

Link: https://lkml.kernel.org/r/20231220224504.646757-34-david@redhat.com
Signed-off-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Muchun Song <songmuchun@bytedance.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

2 files changed, 55 insertions, 6 deletions

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index fef369e37039..7607f862e795 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -308,6 +308,60 @@ static inline void hugetlb_remove_rmap(struct folio *folio)
 	atomic_dec(&folio->_entire_mapcount);
 }
 
+static __always_inline void __folio_dup_file_rmap(struct folio *folio,
+		struct page *page, int nr_pages, enum rmap_level level)
+{
+	__folio_rmap_sanity_checks(folio, page, nr_pages, level);
+
+	switch (level) {
+	case RMAP_LEVEL_PTE:
+		do {
+			atomic_inc(&page->_mapcount);
+		} while (page++, --nr_pages > 0);
+		break;
+	case RMAP_LEVEL_PMD:
+		atomic_inc(&folio->_entire_mapcount);
+		break;
+	}
+}
+
+/**
+ * folio_dup_file_rmap_ptes - duplicate PTE mappings of a page range of a folio
+ * @folio:	The folio to duplicate the mappings of
+ * @page:	The first page to duplicate the mappings of
+ * @nr_pages:	The number of pages of which the mapping will be duplicated
+ *
+ * The page range of the folio is defined by [page, page + nr_pages)
+ *
+ * The caller needs to hold the page table lock.
+ */
+static inline void folio_dup_file_rmap_ptes(struct folio *folio,
+		struct page *page, int nr_pages)
+{
+	__folio_dup_file_rmap(folio, page, nr_pages, RMAP_LEVEL_PTE);
+}
+#define folio_dup_file_rmap_pte(folio, page) \
+	folio_dup_file_rmap_ptes(folio, page, 1)
+
+/**
+ * folio_dup_file_rmap_pmd - duplicate a PMD mapping of a page range of a folio
+ * @folio:	The folio to duplicate the mapping of
+ * @page:	The first page to duplicate the mapping of
+ *
+ * The page range of the folio is defined by [page, page + HPAGE_PMD_NR)
+ *
+ * The caller needs to hold the page table lock.
+ */
+static inline void folio_dup_file_rmap_pmd(struct folio *folio,
+		struct page *page)
+{
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+	__folio_dup_file_rmap(folio, page, HPAGE_PMD_NR, RMAP_LEVEL_PTE);
+#else
+	WARN_ON_ONCE(true);
+#endif
+}
+
 static inline void __page_dup_rmap(struct page *page, bool compound)
 {
 	VM_WARN_ON(folio_test_hugetlb(page_folio(page)));
@@ -322,11 +376,6 @@ static inline void __page_dup_rmap(struct page *page, bool compound)
 	}
 }
 
-static inline void page_dup_file_rmap(struct page *page, bool compound)
-{
-	__page_dup_rmap(page, compound);
-}
-
 /**
  * page_try_dup_anon_rmap - try duplicating a mapping of an already mapped
  *			    anonymous page
diff --git a/mm/memory.c b/mm/memory.c
index e52c6e97444a..fdc87bf15545 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -965,7 +965,7 @@ copy_present_pte(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma,
 		rss[MM_ANONPAGES]++;
 	} else if (page) {
 		folio_get(folio);
-		page_dup_file_rmap(page, false);
+		folio_dup_file_rmap_pte(folio, page);
 		rss[mm_counter_file(page)]++;
 	}