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 #define FRONTSWAP_HAS_EXCLUSIVE_GETS
  23 extern void frontswap_tmem_exclusive_gets(bool);
  24
  25 extern void __frontswap_init(unsigned type);
  26 extern int __frontswap_store(struct page *page);
  27 extern int __frontswap_load(struct page *page);
  28 extern void __frontswap_invalidate_page(unsigned, pgoff_t);
  29 extern void __frontswap_invalidate_area(unsigned);
  30
  31 #ifdef CONFIG_FRONTSWAP
  32
  33 static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  34 {
  35         bool ret = false;
  36
  37         if (frontswap_enabled && sis->frontswap_map)
  38                 ret = test_bit(offset, sis->frontswap_map);
  39         return ret;
  40 }
  41
  42 static inline void frontswap_set(struct swap_info_struct *sis, pgoff_t offset)
  43 {
  44         if (frontswap_enabled && sis->frontswap_map)
  45                 set_bit(offset, sis->frontswap_map);
  46 }
  47
  48 static inline void frontswap_clear(struct swap_info_struct *sis, pgoff_t offset)
  49 {
  50         if (frontswap_enabled && sis->frontswap_map)
  51                 clear_bit(offset, sis->frontswap_map);
  52 }
  53
  54 static inline void frontswap_map_set(struct swap_info_struct *p,
  55                                      unsigned long *map)
  56 {
  57         p->frontswap_map = map;
  58 }
  59
  60 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  61 {
  62         return p->frontswap_map;
  63 }
  64 #else
  65 /* all inline routines become no-ops and all externs are ignored */
  66
  67 #define frontswap_enabled (0)
  68
  69 static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  70 {
  71         return false;
  72 }
  73
  74 static inline void frontswap_set(struct swap_info_struct *sis, pgoff_t offset)
  75 {
  76 }
  77
  78 static inline void frontswap_clear(struct swap_info_struct *sis, pgoff_t offset)
  79 {
  80 }
  81
  82 static inline void frontswap_map_set(struct swap_info_struct *p,
  83                                      unsigned long *map)
  84 {
  85 }
  86
  87 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  88 {
  89         return NULL;
  90 }
  91 #endif
  92
  93 static inline int frontswap_store(struct page *page)
  94 {
  95         int ret = -1;
  96
  97         if (frontswap_enabled)
  98                 ret = __frontswap_store(page);
  99         return ret;
 100 }
 101
 102 static inline int frontswap_load(struct page *page)
 103 {
 104         int ret = -1;
 105
 106         if (frontswap_enabled)
 107                 ret = __frontswap_load(page);
 108         return ret;
 109 }
 110
 111 static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
 112 {
 113         if (frontswap_enabled)
 114                 __frontswap_invalidate_page(type, offset);
 115 }
 116
 117 static inline void frontswap_invalidate_area(unsigned type)
 118 {
 119         if (frontswap_enabled)
 120                 __frontswap_invalidate_area(type);
 121 }
 122
 123 static inline void frontswap_init(unsigned type)
 124 {
 125         if (frontswap_enabled)
 126                 __frontswap_init(type);
 127 }
 128
 129 #endif /* _LINUX_FRONTSWAP_H */