1*4882a593Smuzhiyun /* SPDX-License-Identifier: GPL-2.0 */
2*4882a593Smuzhiyun #ifndef _LINUX_FRONTSWAP_H
3*4882a593Smuzhiyun #define _LINUX_FRONTSWAP_H
4*4882a593Smuzhiyun
5*4882a593Smuzhiyun #include <linux/swap.h>
6*4882a593Smuzhiyun #include <linux/mm.h>
7*4882a593Smuzhiyun #include <linux/bitops.h>
8*4882a593Smuzhiyun #include <linux/jump_label.h>
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun /*
11*4882a593Smuzhiyun * Return code to denote that requested number of
12*4882a593Smuzhiyun * frontswap pages are unused(moved to page cache).
13*4882a593Smuzhiyun * Used in shmem_unuse and try_to_unuse.
14*4882a593Smuzhiyun */
15*4882a593Smuzhiyun #define FRONTSWAP_PAGES_UNUSED 2
16*4882a593Smuzhiyun
17*4882a593Smuzhiyun struct frontswap_ops {
18*4882a593Smuzhiyun void (*init)(unsigned); /* this swap type was just swapon'ed */
19*4882a593Smuzhiyun int (*store)(unsigned, pgoff_t, struct page *); /* store a page */
20*4882a593Smuzhiyun int (*load)(unsigned, pgoff_t, struct page *); /* load a page */
21*4882a593Smuzhiyun void (*invalidate_page)(unsigned, pgoff_t); /* page no longer needed */
22*4882a593Smuzhiyun void (*invalidate_area)(unsigned); /* swap type just swapoff'ed */
23*4882a593Smuzhiyun struct frontswap_ops *next; /* private pointer to next ops */
24*4882a593Smuzhiyun };
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun extern void frontswap_register_ops(struct frontswap_ops *ops);
27*4882a593Smuzhiyun extern void frontswap_shrink(unsigned long);
28*4882a593Smuzhiyun extern unsigned long frontswap_curr_pages(void);
29*4882a593Smuzhiyun extern void frontswap_writethrough(bool);
30*4882a593Smuzhiyun #define FRONTSWAP_HAS_EXCLUSIVE_GETS
31*4882a593Smuzhiyun extern void frontswap_tmem_exclusive_gets(bool);
32*4882a593Smuzhiyun
33*4882a593Smuzhiyun extern bool __frontswap_test(struct swap_info_struct *, pgoff_t);
34*4882a593Smuzhiyun extern void __frontswap_init(unsigned type, unsigned long *map);
35*4882a593Smuzhiyun extern int __frontswap_store(struct page *page);
36*4882a593Smuzhiyun extern int __frontswap_load(struct page *page);
37*4882a593Smuzhiyun extern void __frontswap_invalidate_page(unsigned, pgoff_t);
38*4882a593Smuzhiyun extern void __frontswap_invalidate_area(unsigned);
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun #ifdef CONFIG_FRONTSWAP
41*4882a593Smuzhiyun extern struct static_key_false frontswap_enabled_key;
42*4882a593Smuzhiyun
frontswap_enabled(void)43*4882a593Smuzhiyun static inline bool frontswap_enabled(void)
44*4882a593Smuzhiyun {
45*4882a593Smuzhiyun return static_branch_unlikely(&frontswap_enabled_key);
46*4882a593Smuzhiyun }
47*4882a593Smuzhiyun
frontswap_test(struct swap_info_struct * sis,pgoff_t offset)48*4882a593Smuzhiyun static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
49*4882a593Smuzhiyun {
50*4882a593Smuzhiyun return __frontswap_test(sis, offset);
51*4882a593Smuzhiyun }
52*4882a593Smuzhiyun
frontswap_map_set(struct swap_info_struct * p,unsigned long * map)53*4882a593Smuzhiyun static inline void frontswap_map_set(struct swap_info_struct *p,
54*4882a593Smuzhiyun unsigned long *map)
55*4882a593Smuzhiyun {
56*4882a593Smuzhiyun p->frontswap_map = map;
57*4882a593Smuzhiyun }
58*4882a593Smuzhiyun
frontswap_map_get(struct swap_info_struct * p)59*4882a593Smuzhiyun static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
60*4882a593Smuzhiyun {
61*4882a593Smuzhiyun return p->frontswap_map;
62*4882a593Smuzhiyun }
63*4882a593Smuzhiyun #else
64*4882a593Smuzhiyun /* all inline routines become no-ops and all externs are ignored */
65*4882a593Smuzhiyun
frontswap_enabled(void)66*4882a593Smuzhiyun static inline bool frontswap_enabled(void)
67*4882a593Smuzhiyun {
68*4882a593Smuzhiyun return false;
69*4882a593Smuzhiyun }
70*4882a593Smuzhiyun
frontswap_test(struct swap_info_struct * sis,pgoff_t offset)71*4882a593Smuzhiyun static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
72*4882a593Smuzhiyun {
73*4882a593Smuzhiyun return false;
74*4882a593Smuzhiyun }
75*4882a593Smuzhiyun
frontswap_map_set(struct swap_info_struct * p,unsigned long * map)76*4882a593Smuzhiyun static inline void frontswap_map_set(struct swap_info_struct *p,
77*4882a593Smuzhiyun unsigned long *map)
78*4882a593Smuzhiyun {
79*4882a593Smuzhiyun }
80*4882a593Smuzhiyun
frontswap_map_get(struct swap_info_struct * p)81*4882a593Smuzhiyun static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
82*4882a593Smuzhiyun {
83*4882a593Smuzhiyun return NULL;
84*4882a593Smuzhiyun }
85*4882a593Smuzhiyun #endif
86*4882a593Smuzhiyun
frontswap_store(struct page * page)87*4882a593Smuzhiyun static inline int frontswap_store(struct page *page)
88*4882a593Smuzhiyun {
89*4882a593Smuzhiyun if (frontswap_enabled())
90*4882a593Smuzhiyun return __frontswap_store(page);
91*4882a593Smuzhiyun
92*4882a593Smuzhiyun return -1;
93*4882a593Smuzhiyun }
94*4882a593Smuzhiyun
frontswap_load(struct page * page)95*4882a593Smuzhiyun static inline int frontswap_load(struct page *page)
96*4882a593Smuzhiyun {
97*4882a593Smuzhiyun if (frontswap_enabled())
98*4882a593Smuzhiyun return __frontswap_load(page);
99*4882a593Smuzhiyun
100*4882a593Smuzhiyun return -1;
101*4882a593Smuzhiyun }
102*4882a593Smuzhiyun
frontswap_invalidate_page(unsigned type,pgoff_t offset)103*4882a593Smuzhiyun static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
104*4882a593Smuzhiyun {
105*4882a593Smuzhiyun if (frontswap_enabled())
106*4882a593Smuzhiyun __frontswap_invalidate_page(type, offset);
107*4882a593Smuzhiyun }
108*4882a593Smuzhiyun
frontswap_invalidate_area(unsigned type)109*4882a593Smuzhiyun static inline void frontswap_invalidate_area(unsigned type)
110*4882a593Smuzhiyun {
111*4882a593Smuzhiyun if (frontswap_enabled())
112*4882a593Smuzhiyun __frontswap_invalidate_area(type);
113*4882a593Smuzhiyun }
114*4882a593Smuzhiyun
frontswap_init(unsigned type,unsigned long * map)115*4882a593Smuzhiyun static inline void frontswap_init(unsigned type, unsigned long *map)
116*4882a593Smuzhiyun {
117*4882a593Smuzhiyun #ifdef CONFIG_FRONTSWAP
118*4882a593Smuzhiyun __frontswap_init(type, map);
119*4882a593Smuzhiyun #endif
120*4882a593Smuzhiyun }
121*4882a593Smuzhiyun
122*4882a593Smuzhiyun #endif /* _LINUX_FRONTSWAP_H */
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