1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_FRONTSWAP_H
3 #define _LINUX_FRONTSWAP_H
5 #include <linux/swap.h>
7 #include <linux/bitops.h>
8 #include <linux/jump_label.h>
10 struct frontswap_ops {
11 void (*init)(unsigned); /* this swap type was just swapon'ed */
12 int (*store)(unsigned, pgoff_t, struct page *); /* store a page */
13 int (*load)(unsigned, pgoff_t, struct page *); /* load a page */
14 void (*invalidate_page)(unsigned, pgoff_t); /* page no longer needed */
15 void (*invalidate_area)(unsigned); /* swap type just swapoff'ed */
16 struct frontswap_ops *next; /* private pointer to next ops */
19 extern void frontswap_register_ops(struct frontswap_ops *ops);
21 extern void frontswap_init(unsigned type, unsigned long *map);
22 extern int __frontswap_store(struct page *page);
23 extern int __frontswap_load(struct page *page);
24 extern void __frontswap_invalidate_page(unsigned, pgoff_t);
25 extern void __frontswap_invalidate_area(unsigned);
27 #ifdef CONFIG_FRONTSWAP
28 extern struct static_key_false frontswap_enabled_key;
30 static inline bool frontswap_enabled(void)
32 return static_branch_unlikely(&frontswap_enabled_key);
35 static inline void frontswap_map_set(struct swap_info_struct *p,
38 p->frontswap_map = map;
41 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
43 return p->frontswap_map;
46 /* all inline routines become no-ops and all externs are ignored */
48 static inline bool frontswap_enabled(void)
53 static inline void frontswap_map_set(struct swap_info_struct *p,
58 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
64 static inline int frontswap_store(struct page *page)
66 if (frontswap_enabled())
67 return __frontswap_store(page);
72 static inline int frontswap_load(struct page *page)
74 if (frontswap_enabled())
75 return __frontswap_load(page);
80 static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
82 if (frontswap_enabled())
83 __frontswap_invalidate_page(type, offset);
86 static inline void frontswap_invalidate_area(unsigned type)
88 if (frontswap_enabled())
89 __frontswap_invalidate_area(type);
92 #endif /* _LINUX_FRONTSWAP_H */