Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
tjh.dev
kernel
os
linux
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
10struct 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};
17
18int frontswap_register_ops(const struct frontswap_ops *ops);
19
20extern void frontswap_init(unsigned type, unsigned long *map);
21extern int __frontswap_store(struct page *page);
22extern int __frontswap_load(struct page *page);
23extern void __frontswap_invalidate_page(unsigned, pgoff_t);
24extern void __frontswap_invalidate_area(unsigned);
25
26#ifdef CONFIG_FRONTSWAP
27extern struct static_key_false frontswap_enabled_key;
28
29static inline bool frontswap_enabled(void)
30{
31 return static_branch_unlikely(&frontswap_enabled_key);
32}
33
34static inline void frontswap_map_set(struct swap_info_struct *p,
35 unsigned long *map)
36{
37 p->frontswap_map = map;
38}
39
40static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
41{
42 return p->frontswap_map;
43}
44#else
45/* all inline routines become no-ops and all externs are ignored */
46
47static inline bool frontswap_enabled(void)
48{
49 return false;
50}
51
52static inline void frontswap_map_set(struct swap_info_struct *p,
53 unsigned long *map)
54{
55}
56
57static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
58{
59 return NULL;
60}
61#endif
62
63static inline int frontswap_store(struct page *page)
64{
65 if (frontswap_enabled())
66 return __frontswap_store(page);
67
68 return -1;
69}
70
71static inline int frontswap_load(struct page *page)
72{
73 if (frontswap_enabled())
74 return __frontswap_load(page);
75
76 return -1;
77}
78
79static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
80{
81 if (frontswap_enabled())
82 __frontswap_invalidate_page(type, offset);
83}
84
85static inline void frontswap_invalidate_area(unsigned type)
86{
87 if (frontswap_enabled())
88 __frontswap_invalidate_area(type);
89}
90
91#endif /* _LINUX_FRONTSWAP_H */