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 */
18 int frontswap_register_ops(const struct frontswap_ops *ops);
20 extern void frontswap_init(unsigned type, unsigned long *map);
21 extern int __frontswap_store(struct page *page);
22 extern int __frontswap_load(struct page *page);
23 extern void __frontswap_invalidate_page(unsigned, pgoff_t);
24 extern void __frontswap_invalidate_area(unsigned);
26 #ifdef CONFIG_FRONTSWAP
27 extern struct static_key_false frontswap_enabled_key;
29 static inline bool frontswap_enabled(void)
31 return static_branch_unlikely(&frontswap_enabled_key);
34 static inline void frontswap_map_set(struct swap_info_struct *p,
37 p->frontswap_map = map;
40 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
42 return p->frontswap_map;
45 /* all inline routines become no-ops and all externs are ignored */
47 static inline bool frontswap_enabled(void)
52 static inline void frontswap_map_set(struct swap_info_struct *p,
57 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
63 static inline int frontswap_store(struct page *page)
65 if (frontswap_enabled())
66 return __frontswap_store(page);
71 static inline int frontswap_load(struct page *page)
73 if (frontswap_enabled())
74 return __frontswap_load(page);
79 static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
81 if (frontswap_enabled())
82 __frontswap_invalidate_page(type, offset);
85 static inline void frontswap_invalidate_area(unsigned type)
87 if (frontswap_enabled())
88 __frontswap_invalidate_area(type);
91 #endif /* _LINUX_FRONTSWAP_H */