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-rw-r--r--include/linux/frontswap.h127
1 files changed, 127 insertions, 0 deletions
diff --git a/include/linux/frontswap.h b/include/linux/frontswap.h
new file mode 100644
index 000000000000..0e4e2eec5c1d
--- /dev/null
+++ b/include/linux/frontswap.h
@@ -0,0 +1,127 @@
+#ifndef _LINUX_FRONTSWAP_H
+#define _LINUX_FRONTSWAP_H
+
+#include <linux/swap.h>
+#include <linux/mm.h>
+#include <linux/bitops.h>
+
+struct frontswap_ops {
+ void (*init)(unsigned);
+ int (*store)(unsigned, pgoff_t, struct page *);
+ int (*load)(unsigned, pgoff_t, struct page *);
+ void (*invalidate_page)(unsigned, pgoff_t);
+ void (*invalidate_area)(unsigned);
+};
+
+extern bool frontswap_enabled;
+extern struct frontswap_ops
+ frontswap_register_ops(struct frontswap_ops *ops);
+extern void frontswap_shrink(unsigned long);
+extern unsigned long frontswap_curr_pages(void);
+extern void frontswap_writethrough(bool);
+
+extern void __frontswap_init(unsigned type);
+extern int __frontswap_store(struct page *page);
+extern int __frontswap_load(struct page *page);
+extern void __frontswap_invalidate_page(unsigned, pgoff_t);
+extern void __frontswap_invalidate_area(unsigned);
+
+#ifdef CONFIG_FRONTSWAP
+
+static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
+{
+ bool ret = false;
+
+ if (frontswap_enabled && sis->frontswap_map)
+ ret = test_bit(offset, sis->frontswap_map);
+ return ret;
+}
+
+static inline void frontswap_set(struct swap_info_struct *sis, pgoff_t offset)
+{
+ if (frontswap_enabled && sis->frontswap_map)
+ set_bit(offset, sis->frontswap_map);
+}
+
+static inline void frontswap_clear(struct swap_info_struct *sis, pgoff_t offset)
+{
+ if (frontswap_enabled && sis->frontswap_map)
+ clear_bit(offset, sis->frontswap_map);
+}
+
+static inline void frontswap_map_set(struct swap_info_struct *p,
+ unsigned long *map)
+{
+ p->frontswap_map = map;
+}
+
+static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
+{
+ return p->frontswap_map;
+}
+#else
+/* all inline routines become no-ops and all externs are ignored */
+
+#define frontswap_enabled (0)
+
+static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
+{
+ return false;
+}
+
+static inline void frontswap_set(struct swap_info_struct *sis, pgoff_t offset)
+{
+}
+
+static inline void frontswap_clear(struct swap_info_struct *sis, pgoff_t offset)
+{
+}
+
+static inline void frontswap_map_set(struct swap_info_struct *p,
+ unsigned long *map)
+{
+}
+
+static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
+{
+ return NULL;
+}
+#endif
+
+static inline int frontswap_store(struct page *page)
+{
+ int ret = -1;
+
+ if (frontswap_enabled)
+ ret = __frontswap_store(page);
+ return ret;
+}
+
+static inline int frontswap_load(struct page *page)
+{
+ int ret = -1;
+
+ if (frontswap_enabled)
+ ret = __frontswap_load(page);
+ return ret;
+}
+
+static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
+{
+ if (frontswap_enabled)
+ __frontswap_invalidate_page(type, offset);
+}
+
+static inline void frontswap_invalidate_area(unsigned type)
+{
+ if (frontswap_enabled)
+ __frontswap_invalidate_area(type);
+}
+
+static inline void frontswap_init(unsigned type)
+{
+ if (frontswap_enabled)
+ __frontswap_init(type);
+}
+
+#endif /* _LINUX_FRONTSWAP_H */