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); /* this swap type was just swapon'ed */
  10         int (*store)(unsigned, pgoff_t, struct page *); /* store a page */
  11         int (*load)(unsigned, pgoff_t, struct page *); /* load a page */
  12         void (*invalidate_page)(unsigned, pgoff_t); /* page no longer needed */
  13         void (*invalidate_area)(unsigned); /* swap type just swapoff'ed */
  14         struct frontswap_ops *next; /* private pointer to next ops */
  15 };
  16
  17 extern bool frontswap_enabled;
  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 #define frontswap_enabled (1)
  34
  35 static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  36 {
  37         return __frontswap_test(sis, offset);
  38 }
  39
  40 static inline void frontswap_map_set(struct swap_info_struct *p,
  41                                      unsigned long *map)
  42 {
  43         p->frontswap_map = map;
  44 }
  45
  46 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  47 {
  48         return p->frontswap_map;
  49 }
  50 #else
  51 /* all inline routines become no-ops and all externs are ignored */
  52
  53 #define frontswap_enabled (0)
  54
  55 static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  56 {
  57         return false;
  58 }
  59
  60 static inline void frontswap_map_set(struct swap_info_struct *p,
  61                                      unsigned long *map)
  62 {
  63 }
  64
  65 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  66 {
  67         return NULL;
  68 }
  69 #endif
  70
  71 static inline int frontswap_store(struct page *page)
  72 {
  73         int ret = -1;
  74
  75         if (frontswap_enabled)
  76                 ret = __frontswap_store(page);
  77         return ret;
  78 }
  79
  80 static inline int frontswap_load(struct page *page)
  81 {
  82         int ret = -1;
  83
  84         if (frontswap_enabled)
  85                 ret = __frontswap_load(page);
  86         return ret;
  87 }
  88
  89 static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
  90 {
  91         if (frontswap_enabled)
  92                 __frontswap_invalidate_page(type, offset);
  93 }
  94
  95 static inline void frontswap_invalidate_area(unsigned type)
  96 {
  97         if (frontswap_enabled)
  98                 __frontswap_invalidate_area(type);
  99 }
 100
 101 static inline void frontswap_init(unsigned type, unsigned long *map)
 102 {
 103         if (frontswap_enabled)
 104                 __frontswap_init(type, map);
 105 }
 106
 107 #endif /* _LINUX_FRONTSWAP_H */