include/linux/frontswap.h

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