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
   7 struct frontswap_ops {
   8         void (*init)(unsigned);
   9         int (*put_page)(unsigned, pgoff_t, struct page *);
  10         int (*get_page)(unsigned, pgoff_t, struct page *);
  11         void (*flush_page)(unsigned, pgoff_t);
  12         void (*flush_area)(unsigned);
  13 };
  14
  15 extern int frontswap_enabled;
  16 extern struct frontswap_ops
  17         frontswap_register_ops(struct frontswap_ops *ops);
  18 extern void frontswap_shrink(unsigned long);
  19 extern unsigned long frontswap_curr_pages(void);
  20
  21 extern void __frontswap_init(unsigned type);
  22 extern int __frontswap_put_page(struct page *page);
  23 extern int __frontswap_get_page(struct page *page);
  24 extern void __frontswap_flush_page(unsigned, pgoff_t);
  25 extern void __frontswap_flush_area(unsigned);
  26
  27 #ifdef CONFIG_FRONTSWAP
  28
  29 static inline int frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  30 {
  31         int ret = 0;
  32
  33         if (frontswap_enabled && sis->frontswap_map)
  34                 ret = test_bit(offset, sis->frontswap_map);
  35         return ret;
  36 }
  37
  38 static inline void frontswap_set(struct swap_info_struct *sis, pgoff_t offset)
  39 {
  40         if (frontswap_enabled && sis->frontswap_map)
  41                 set_bit(offset, sis->frontswap_map);
  42 }
  43
  44 static inline void frontswap_clear(struct swap_info_struct *sis, pgoff_t offset)
  45 {
  46         if (frontswap_enabled && sis->frontswap_map)
  47                 clear_bit(offset, sis->frontswap_map);
  48 }
  49
  50 static inline void frontswap_map_set(struct swap_info_struct *p,
  51                                      unsigned long *map)
  52 {
  53         p->frontswap_map = map;
  54 }
  55
  56 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  57 {
  58         return p->frontswap_map;
  59 }
  60 #else
  61 /* all inline routines become no-ops and all externs are ignored */
  62
  63 #define frontswap_enabled (0)
  64
  65 static inline int frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  66 {
  67         return 0;
  68 }
  69
  70 static inline void frontswap_set(struct swap_info_struct *sis, pgoff_t offset)
  71 {
  72 }
  73
  74 static inline void frontswap_clear(struct swap_info_struct *sis, pgoff_t offset)
  75 {
  76 }
  77
  78 static inline void frontswap_map_set(struct swap_info_struct *p,
  79                                      unsigned long *map)
  80 {
  81 }
  82
  83 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  84 {
  85         return NULL;
  86 }
  87 #endif
  88
  89 static inline int frontswap_put_page(struct page *page)
  90 {
  91         int ret = -1;
  92
  93         if (frontswap_enabled)
  94                 ret = __frontswap_put_page(page);
  95         return ret;
  96 }
  97
  98 static inline int frontswap_get_page(struct page *page)
  99 {
 100         int ret = -1;
 101
 102         if (frontswap_enabled)
 103                 ret = __frontswap_get_page(page);
 104         return ret;
 105 }
 106
 107 static inline void frontswap_flush_page(unsigned type, pgoff_t offset)
 108 {
 109         if (frontswap_enabled)
 110                 __frontswap_flush_page(type, offset);
 111 }
 112
 113 static inline void frontswap_flush_area(unsigned type)
 114 {
 115         if (frontswap_enabled)
 116                 __frontswap_flush_area(type);
 117 }
 118
 119 static inline void frontswap_init(unsigned type)
 120 {
 121         if (frontswap_enabled)
 122                 __frontswap_init(type);
 123 }
 124
 125 #endif /* _LINUX_FRONTSWAP_H */