1 files changed, 35 insertions, 7 deletions

diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 8b611e131..5240bd7bc 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -210,8 +210,8 @@ struct page {
  *
  * An 'encoded_page' pointer is a pointer to a regular 'struct page', but
  * with the low bits of the pointer indicating extra context-dependent
- * information. Not super-common, but happens in mmu_gather and mlock
- * handling, and this acts as a type system check on that use.
+ * information. Only used in mmu_gather handling, and this acts as a type
+ * system check on that use.
  *
  * We only really have two guaranteed bits in general, although you could
  * play with 'struct page' alignment (see CONFIG_HAVE_ALIGNED_STRUCT_PAGE)
@@ -220,21 +220,46 @@ struct page {
  * Use the supplied helper functions to endcode/decode the pointer and bits.
  */
 struct encoded_page;
-#define ENCODE_PAGE_BITS 3ul
+
+#define ENCODED_PAGE_BITS			3ul
+
+/* Perform rmap removal after we have flushed the TLB. */
+#define ENCODED_PAGE_BIT_DELAY_RMAP		1ul
+
+/*
+ * The next item in an encoded_page array is the "nr_pages" argument, specifying
+ * the number of consecutive pages starting from this page, that all belong to
+ * the same folio. For example, "nr_pages" corresponds to the number of folio
+ * references that must be dropped. If this bit is not set, "nr_pages" is
+ * implicitly 1.
+ */
+#define ENCODED_PAGE_BIT_NR_PAGES_NEXT		2ul
+
 static __always_inline struct encoded_page *encode_page(struct page *page, unsigned long flags)
 {
-	BUILD_BUG_ON(flags > ENCODE_PAGE_BITS);
+	BUILD_BUG_ON(flags > ENCODED_PAGE_BITS);
 	return (struct encoded_page *)(flags | (unsigned long)page);
 }
 
 static inline unsigned long encoded_page_flags(struct encoded_page *page)
 {
-	return ENCODE_PAGE_BITS & (unsigned long)page;
+	return ENCODED_PAGE_BITS & (unsigned long)page;
 }
 
 static inline struct page *encoded_page_ptr(struct encoded_page *page)
 {
-	return (struct page *)(~ENCODE_PAGE_BITS & (unsigned long)page);
+	return (struct page *)(~ENCODED_PAGE_BITS & (unsigned long)page);
+}
+
+static __always_inline struct encoded_page *encode_nr_pages(unsigned long nr)
+{
+	VM_WARN_ON_ONCE((nr << 2) >> 2 != nr);
+	return (struct encoded_page *)(nr << 2);
+}
+
+static __always_inline unsigned long encoded_nr_pages(struct encoded_page *page)
+{
+	return ((unsigned long)page) >> 2;
 }
 
 /*
@@ -394,12 +419,13 @@ FOLIO_MATCH(compound_head, _head_2a);
 
 /**
  * struct ptdesc -    Memory descriptor for page tables.
- * @__page_flags:     Same as page flags. Unused for page tables.
+ * @__page_flags:     Same as page flags. Powerpc only.
  * @pt_rcu_head:      For freeing page table pages.
  * @pt_list:          List of used page tables. Used for s390 and x86.
  * @_pt_pad_1:        Padding that aliases with page's compound head.
  * @pmd_huge_pte:     Protected by ptdesc->ptl, used for THPs.
  * @__page_mapping:   Aliases with page->mapping. Unused for page tables.
+ * @pt_index:         Used for s390 gmap.
  * @pt_mm:            Used for x86 pgds.
  * @pt_frag_refcount: For fragmented page table tracking. Powerpc only.
  * @_pt_pad_2:        Padding to ensure proper alignment.
@@ -425,6 +451,7 @@ struct ptdesc {
 	unsigned long __page_mapping;
 
 	union {
+		pgoff_t pt_index;
 		struct mm_struct *pt_mm;
 		atomic_t pt_frag_refcount;
 	};
@@ -450,6 +477,7 @@ TABLE_MATCH(flags, __page_flags);
 TABLE_MATCH(compound_head, pt_list);
 TABLE_MATCH(compound_head, _pt_pad_1);
 TABLE_MATCH(mapping, __page_mapping);
+TABLE_MATCH(index, pt_index);
 TABLE_MATCH(rcu_head, pt_rcu_head);
 TABLE_MATCH(page_type, __page_type);
 TABLE_MATCH(_refcount, __page_refcount);