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-rw-r--r--include/linux/mm_types.h30
1 files changed, 29 insertions, 1 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 8f30f262431c..5c87d0f292a2 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -245,6 +245,13 @@ struct page {
* @_refcount: Do not access this member directly. Use folio_ref_count()
* to find how many references there are to this folio.
* @memcg_data: Memory Control Group data.
+ * @_flags_1: For large folios, additional page flags.
+ * @__head: Points to the folio. Do not use.
+ * @_folio_dtor: Which destructor to use for this folio.
+ * @_folio_order: Do not use directly, call folio_order().
+ * @_total_mapcount: Do not use directly, call folio_entire_mapcount().
+ * @_pincount: Do not use directly, call folio_maybe_dma_pinned().
+ * @_folio_nr_pages: Do not use directly, call folio_nr_pages().
*
* A folio is a physically, virtually and logically contiguous set
* of bytes. It is a power-of-two in size, and it is aligned to that
@@ -283,9 +290,17 @@ struct folio {
};
struct page page;
};
+ unsigned long _flags_1;
+ unsigned long __head;
+ unsigned char _folio_dtor;
+ unsigned char _folio_order;
+ atomic_t _total_mapcount;
+ atomic_t _pincount;
+#ifdef CONFIG_64BIT
+ unsigned int _folio_nr_pages;
+#endif
};
-static_assert(sizeof(struct page) == sizeof(struct folio));
#define FOLIO_MATCH(pg, fl) \
static_assert(offsetof(struct page, pg) == offsetof(struct folio, fl))
FOLIO_MATCH(flags, flags);
@@ -300,6 +315,19 @@ FOLIO_MATCH(_refcount, _refcount);
FOLIO_MATCH(memcg_data, memcg_data);
#endif
#undef FOLIO_MATCH
+#define FOLIO_MATCH(pg, fl) \
+ static_assert(offsetof(struct folio, fl) == \
+ offsetof(struct page, pg) + sizeof(struct page))
+FOLIO_MATCH(flags, _flags_1);
+FOLIO_MATCH(compound_head, __head);
+FOLIO_MATCH(compound_dtor, _folio_dtor);
+FOLIO_MATCH(compound_order, _folio_order);
+FOLIO_MATCH(compound_mapcount, _total_mapcount);
+FOLIO_MATCH(compound_pincount, _pincount);
+#ifdef CONFIG_64BIT
+FOLIO_MATCH(compound_nr, _folio_nr_pages);
+#endif
+#undef FOLIO_MATCH
static inline atomic_t *folio_mapcount_ptr(struct folio *folio)
{