root/include/linux/frontswap.h

INCLUDED FROM

DEFINITIONS

1. frontswap_enabled
2. frontswap_test
3. frontswap_map_set
4. frontswap_map_get
5. frontswap_enabled
6. frontswap_test
7. frontswap_map_set
8. frontswap_map_get
9. frontswap_store
10. frontswap_load
11. frontswap_invalidate_page
12. frontswap_invalidate_area
13. frontswap_init

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