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
   8 struct frontswap_ops {
   9         void (*init)(unsigned);
  10         int (*store)(unsigned, pgoff_t, struct page *);
  11         int (*load)(unsigned, pgoff_t, struct page *);
  12         void (*invalidate_page)(unsigned, pgoff_t);
  13         void (*invalidate_area)(unsigned);
  14 };
  15
  16 extern bool frontswap_enabled;
  17 extern struct frontswap_ops
  18         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
  23 extern void __frontswap_init(unsigned type);
  24 extern int __frontswap_store(struct page *page);
  25 extern int __frontswap_load(struct page *page);
  26 extern void __frontswap_invalidate_page(unsigned, pgoff_t);
  27 extern void __frontswap_invalidate_area(unsigned);
  28
  29 #ifdef CONFIG_FRONTSWAP
  30
  31 static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  32 {
  33         bool ret = false;
  34
  35         if (frontswap_enabled && sis->frontswap_map)
  36                 ret = test_bit(offset, sis->frontswap_map);
  37         return ret;
  38 }
  39
  40 static inline void frontswap_set(struct swap_info_struct *sis, pgoff_t offset)
  41 {
  42         if (frontswap_enabled && sis->frontswap_map)
  43                 set_bit(offset, sis->frontswap_map);
  44 }
  45
  46 static inline void frontswap_clear(struct swap_info_struct *sis, pgoff_t offset)
  47 {
  48         if (frontswap_enabled && sis->frontswap_map)
  49                 clear_bit(offset, sis->frontswap_map);
  50 }
  51
  52 static inline void frontswap_map_set(struct swap_info_struct *p,
  53                                      unsigned long *map)
  54 {
  55         p->frontswap_map = map;
  56 }
  57
  58 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  59 {
  60         return p->frontswap_map;
  61 }
  62 #else
  63 /* all inline routines become no-ops and all externs are ignored */
  64
  65 #define frontswap_enabled (0)
  66
  67 static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  68 {
  69         return false;
  70 }
  71
  72 static inline void frontswap_set(struct swap_info_struct *sis, pgoff_t offset)
  73 {
  74 }
  75
  76 static inline void frontswap_clear(struct swap_info_struct *sis, pgoff_t offset)
  77 {
  78 }
  79
  80 static inline void frontswap_map_set(struct swap_info_struct *p,
  81                                      unsigned long *map)
  82 {
  83 }
  84
  85 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  86 {
  87         return NULL;
  88 }
  89 #endif
  90
  91 static inline int frontswap_store(struct page *page)
  92 {
  93         int ret = -1;
  94
  95         if (frontswap_enabled)
  96                 ret = __frontswap_store(page);
  97         return ret;
  98 }
  99
 100 static inline int frontswap_load(struct page *page)
 101 {
 102         int ret = -1;
 103
 104         if (frontswap_enabled)
 105                 ret = __frontswap_load(page);
 106         return ret;
 107 }
 108
 109 static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
 110 {
 111         if (frontswap_enabled)
 112                 __frontswap_invalidate_page(type, offset);
 113 }
 114
 115 static inline void frontswap_invalidate_area(unsigned type)
 116 {
 117         if (frontswap_enabled)
 118                 __frontswap_invalidate_area(type);
 119 }
 120
 121 static inline void frontswap_init(unsigned type)
 122 {
 123         if (frontswap_enabled)
 124                 __frontswap_init(type);
 125 }
 126
 127 #endif /* _LINUX_FRONTSWAP_H */