[PATCH v1 05/17] mm/rmap: pass dst_vma to page_try_dup_anon_rmap() and page_dup_file_rmap()

[David Hildenbrand <david@redhat.com>]

We'll need access to the destination MM when modifying the total mapcount
of a non-hugetlb large folios next. So pass in the destination VMA.

Signed-off-by: David Hildenbrand <david@redhat.com>
---
 include/linux/rmap.h | 42 +++++++++++++++++++++++++-----------------
 mm/huge_memory.c     |  2 +-
 mm/memory.c          | 10 +++++-----
 3 files changed, 31 insertions(+), 23 deletions(-)

diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 91b5935e8485e..9e275986f0ef6 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -322,7 +322,8 @@ static inline void hugetlb_remove_rmap(struct folio *folio)
 }
 
 static __always_inline void __folio_dup_file_rmap(struct folio *folio,
-		struct page *page, int nr_pages, enum rmap_level level)
+		struct page *page, int nr_pages, struct vm_area_struct *dst_vma,
+		enum rmap_level level)
 {
 	const int orig_nr_pages = nr_pages;
 
@@ -352,45 +353,47 @@ static __always_inline void __folio_dup_file_rmap(struct folio *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
+ * @dst_vma:	The destination vm area
  *
  * 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)
+		struct page *page, int nr_pages, struct vm_area_struct *dst_vma)
 {
-	__folio_dup_file_rmap(folio, page, nr_pages, RMAP_LEVEL_PTE);
+	__folio_dup_file_rmap(folio, page, nr_pages, dst_vma, RMAP_LEVEL_PTE);
 }
 
 static __always_inline void folio_dup_file_rmap_pte(struct folio *folio,
-		struct page *page)
+		struct page *page, struct vm_area_struct *dst_vma)
 {
-	__folio_dup_file_rmap(folio, page, 1, RMAP_LEVEL_PTE);
+	__folio_dup_file_rmap(folio, page, 1, dst_vma, RMAP_LEVEL_PTE);
 }
 
 /**
  * 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
+ * @dst_vma:	The destination vm area
  *
  * 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)
+		struct page *page, struct vm_area_struct *dst_vma)
 {
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	__folio_dup_file_rmap(folio, page, HPAGE_PMD_NR, RMAP_LEVEL_PTE);
+	__folio_dup_file_rmap(folio, page, HPAGE_PMD_NR, dst_vma, RMAP_LEVEL_PTE);
 #else
 	WARN_ON_ONCE(true);
 #endif
 }
 
 static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio,
-		struct page *page, int nr_pages, struct vm_area_struct *src_vma,
-		enum rmap_level level)
+		struct page *page, int nr_pages, struct vm_area_struct *dst_vma,
+		struct vm_area_struct *src_vma, enum rmap_level level)
 {
 	const int orig_nr_pages = nr_pages;
 	bool maybe_pinned;
@@ -455,6 +458,7 @@ static __always_inline int __folio_try_dup_anon_rmap(struct folio *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
+ * @dst_vma:	The destination vm area
  * @src_vma:	The vm area from which the mappings are duplicated
  *
  * The page range of the folio is defined by [page, page + nr_pages)
@@ -473,16 +477,18 @@ static __always_inline int __folio_try_dup_anon_rmap(struct folio *folio,
  * Returns 0 if duplicating the mappings succeeded. Returns -EBUSY otherwise.
  */
 static inline int folio_try_dup_anon_rmap_ptes(struct folio *folio,
-		struct page *page, int nr_pages, struct vm_area_struct *src_vma)
+		struct page *page, int nr_pages, struct vm_area_struct *dst_vma,
+		struct vm_area_struct *src_vma)
 {
-	return __folio_try_dup_anon_rmap(folio, page, nr_pages, src_vma,
-					 RMAP_LEVEL_PTE);
+	return __folio_try_dup_anon_rmap(folio, page, nr_pages, dst_vma,
+					 src_vma, RMAP_LEVEL_PTE);
 }
 
 static __always_inline int folio_try_dup_anon_rmap_pte(struct folio *folio,
-		struct page *page, struct vm_area_struct *src_vma)
+		struct page *page, struct vm_area_struct *dst_vma,
+		struct vm_area_struct *src_vma)
 {
-	return __folio_try_dup_anon_rmap(folio, page, 1, src_vma,
+	return __folio_try_dup_anon_rmap(folio, page, 1, dst_vma, src_vma,
 					 RMAP_LEVEL_PTE);
 }
 
@@ -491,6 +497,7 @@ static __always_inline int folio_try_dup_anon_rmap_pte(struct folio *folio,
  *				 of a folio
  * @folio:	The folio to duplicate the mapping of
  * @page:	The first page to duplicate the mapping of
+ * @dst_vma:	The destination vm area
  * @src_vma:	The vm area from which the mapping is duplicated
  *
  * The page range of the folio is defined by [page, page + HPAGE_PMD_NR)
@@ -509,11 +516,12 @@ static __always_inline int folio_try_dup_anon_rmap_pte(struct folio *folio,
  * Returns 0 if duplicating the mapping succeeded. Returns -EBUSY otherwise.
  */
 static inline int folio_try_dup_anon_rmap_pmd(struct folio *folio,
-		struct page *page, struct vm_area_struct *src_vma)
+		struct page *page, struct vm_area_struct *dst_vma,
+		struct vm_area_struct *src_vma)
 {
 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	return __folio_try_dup_anon_rmap(folio, page, HPAGE_PMD_NR, src_vma,
-					 RMAP_LEVEL_PMD);
+	return __folio_try_dup_anon_rmap(folio, page, HPAGE_PMD_NR, dst_vma,
+					 src_vma, RMAP_LEVEL_PMD);
 #else
 	WARN_ON_ONCE(true);
 	return -EBUSY;
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 28d12573fcf8c..6de84377e8e77 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1642,7 +1642,7 @@ int copy_huge_pmd(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 	src_folio = page_folio(src_page);
 
 	folio_get(src_folio);
-	if (unlikely(folio_try_dup_anon_rmap_pmd(src_folio, src_page, src_vma))) {
+	if (unlikely(folio_try_dup_anon_rmap_pmd(src_folio, src_page, dst_vma, src_vma))) {
 		/* Page maybe pinned: split and retry the fault on PTEs. */
 		folio_put(src_folio);
 		pte_free(dst_mm, pgtable);
diff --git a/mm/memory.c b/mm/memory.c
index 06b42db8a2db7..c2143c40a134b 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -856,7 +856,7 @@ copy_nonpresent_pte(struct mm_struct *dst_mm, struct mm_struct *src_mm,
 		folio_get(folio);
 		rss[mm_counter(folio)]++;
 		/* Cannot fail as these pages cannot get pinned. */
-		folio_try_dup_anon_rmap_pte(folio, page, src_vma);
+		folio_try_dup_anon_rmap_pte(folio, page, dst_vma, src_vma);
 
 		/*
 		 * We do not preserve soft-dirty information, because so
@@ -1007,14 +1007,14 @@ copy_present_ptes(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma
 		folio_ref_add(folio, nr);
 		if (folio_test_anon(folio)) {
 			if (unlikely(folio_try_dup_anon_rmap_ptes(folio, page,
-								  nr, src_vma))) {
+								  nr, dst_vma, src_vma))) {
 				folio_ref_sub(folio, nr);
 				return -EAGAIN;
 			}
 			rss[MM_ANONPAGES] += nr;
 			VM_WARN_ON_FOLIO(PageAnonExclusive(page), folio);
 		} else {
-			folio_dup_file_rmap_ptes(folio, page, nr);
+			folio_dup_file_rmap_ptes(folio, page, nr, dst_vma);
 			rss[mm_counter_file(folio)] += nr;
 		}
 		if (any_writable)
@@ -1032,7 +1032,7 @@ copy_present_ptes(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma
 		 * guarantee the pinned page won't be randomly replaced in the
 		 * future.
 		 */
-		if (unlikely(folio_try_dup_anon_rmap_pte(folio, page, src_vma))) {
+		if (unlikely(folio_try_dup_anon_rmap_pte(folio, page, dst_vma, src_vma))) {
 			/* Page may be pinned, we have to copy. */
 			folio_put(folio);
 			err = copy_present_page(dst_vma, src_vma, dst_pte, src_pte,
@@ -1042,7 +1042,7 @@ copy_present_ptes(struct vm_area_struct *dst_vma, struct vm_area_struct *src_vma
 		rss[MM_ANONPAGES]++;
 		VM_WARN_ON_FOLIO(PageAnonExclusive(page), folio);
 	} else {
-		folio_dup_file_rmap_pte(folio, page);
+		folio_dup_file_rmap_pte(folio, page, dst_vma);
 		rss[mm_counter_file(folio)]++;
 	}
 
-- 
2.46.0