Introduce basic utility functions for zsdesc to avoid directly accessing
fields of struct page. More helpers will be defined later.
zsdesc_page() is defined with _Generic to preserve constness.
page_zsdesc() does not call compound_head() because zsdesc is always
a base page.
Signed-off-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
---
mm/zsmalloc.c | 33 +++++++++++++++++++++++++++++++++
1 file changed, 33 insertions(+)
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 60ce2a4dfeeb..47df9103787e 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -274,6 +274,39 @@ ZSDESC_MATCH(_refcount, __page_refcount);
#undef ZSDESC_MATCH
static_assert(sizeof(struct zsdesc) <= sizeof(struct page));
+#define zsdesc_page(zdesc) (_Generic((zdesc), \
+ const struct zsdesc *: (const struct page *)zdesc, \
+ struct zsdesc *: (struct page *)zdesc))
+
+static inline struct zsdesc *page_zsdesc(struct page *page)
+{
+ return (struct zsdesc *)page;
+}
+
+static inline unsigned long zsdesc_pfn(const struct zsdesc *zsdesc)
+{
+ return page_to_pfn(zsdesc_page(zsdesc));
+}
+
+static inline struct zsdesc *pfn_zsdesc(unsigned long pfn)
+{
+ return page_zsdesc(pfn_to_page(pfn));
+}
+
+static inline void zsdesc_get(struct zsdesc *zsdesc)
+{
+ struct folio *folio = (struct folio *)zsdesc;
+
+ folio_get(folio);
+}
+
+static inline void zsdesc_put(struct zsdesc *zsdesc)
+{
+ struct folio *folio = (struct folio *)zsdesc;
+
+ folio_put(folio);
+}
+
struct zspage {
struct {
unsigned int huge:HUGE_BITS;
--
2.39.3
