1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _LINUX_FRONTSWAP_H
3 #define _LINUX_FRONTSWAP_H
4
5 #include <linux/swap.h>
6 #include <linux/mm.h>
7 #include <linux/bitops.h>
8 #include <linux/jump_label.h>
9
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 */
17 };
18
19 extern void frontswap_register_ops(struct frontswap_ops *ops);
20 extern void frontswap_shrink(unsigned long);
21 extern unsigned long frontswap_curr_pages(void);
22 extern void frontswap_writethrough(bool);
23 #define FRONTSWAP_HAS_EXCLUSIVE_GETS
24 extern void frontswap_tmem_exclusive_gets(bool);
25
26 extern bool __frontswap_test(struct swap_info_struct *, pgoff_t);
27 extern void __frontswap_init(unsigned type, unsigned long *map);
28 extern int __frontswap_store(struct page *page);
29 extern int __frontswap_load(struct page *page);
30 extern void __frontswap_invalidate_page(unsigned, pgoff_t);
31 extern void __frontswap_invalidate_area(unsigned);
32
33 #ifdef CONFIG_FRONTSWAP
34 extern struct static_key_false frontswap_enabled_key;
35
frontswap_enabled(void)36 static inline bool frontswap_enabled(void)
37 {
38 return static_branch_unlikely(&frontswap_enabled_key);
39 }
40
frontswap_test(struct swap_info_struct * sis,pgoff_t offset)41 static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
42 {
43 return __frontswap_test(sis, offset);
44 }
45
frontswap_map_set(struct swap_info_struct * p,unsigned long * map)46 static inline void frontswap_map_set(struct swap_info_struct *p,
47 unsigned long *map)
48 {
49 p->frontswap_map = map;
50 }
51
frontswap_map_get(struct swap_info_struct * p)52 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
53 {
54 return p->frontswap_map;
55 }
56 #else
57 /* all inline routines become no-ops and all externs are ignored */
58
frontswap_enabled(void)59 static inline bool frontswap_enabled(void)
60 {
61 return false;
62 }
63
frontswap_test(struct swap_info_struct * sis,pgoff_t offset)64 static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
65 {
66 return false;
67 }
68
frontswap_map_set(struct swap_info_struct * p,unsigned long * map)69 static inline void frontswap_map_set(struct swap_info_struct *p,
70 unsigned long *map)
71 {
72 }
73
frontswap_map_get(struct swap_info_struct * p)74 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
75 {
76 return NULL;
77 }
78 #endif
79
frontswap_store(struct page * page)80 static inline int frontswap_store(struct page *page)
81 {
82 if (frontswap_enabled())
83 return __frontswap_store(page);
84
85 return -1;
86 }
87
frontswap_load(struct page * page)88 static inline int frontswap_load(struct page *page)
89 {
90 if (frontswap_enabled())
91 return __frontswap_load(page);
92
93 return -1;
94 }
95
frontswap_invalidate_page(unsigned type,pgoff_t offset)96 static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
97 {
98 if (frontswap_enabled())
99 __frontswap_invalidate_page(type, offset);
100 }
101
frontswap_invalidate_area(unsigned type)102 static inline void frontswap_invalidate_area(unsigned type)
103 {
104 if (frontswap_enabled())
105 __frontswap_invalidate_area(type);
106 }
107
frontswap_init(unsigned type,unsigned long * map)108 static inline void frontswap_init(unsigned type, unsigned long *map)
109 {
110 #ifdef CONFIG_FRONTSWAP
111 __frontswap_init(type, map);
112 #endif
113 }
114
115 #endif /* _LINUX_FRONTSWAP_H */
116