LXR linux/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
   8struct 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
  17extern bool frontswap_enabled;
  18extern void frontswap_register_ops(struct frontswap_ops *ops);
  19extern void frontswap_shrink(unsigned long);
  20extern unsigned long frontswap_curr_pages(void);
  21extern void frontswap_writethrough(bool);
  22#define FRONTSWAP_HAS_EXCLUSIVE_GETS
  23extern void frontswap_tmem_exclusive_gets(bool);
  24
  25extern bool __frontswap_test(struct swap_info_struct *, pgoff_t);
  26extern void __frontswap_init(unsigned type, unsigned long *map);
  27extern int __frontswap_store(struct page *page);
  28extern int __frontswap_load(struct page *page);
  29extern void __frontswap_invalidate_page(unsigned, pgoff_t);
  30extern void __frontswap_invalidate_area(unsigned);
  31
  32#ifdef CONFIG_FRONTSWAP
  33#define frontswap_enabled (1)
  34
  35static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  36{
  37        return __frontswap_test(sis, offset);
  38}
  39
  40static inline void frontswap_map_set(struct swap_info_struct *p,
  41                                     unsigned long *map)
  42{
  43        p->frontswap_map = map;
  44}
  45
  46static 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
  55static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  56{
  57        return false;
  58}
  59
  60static inline void frontswap_map_set(struct swap_info_struct *p,
  61                                     unsigned long *map)
  62{
  63}
  64
  65static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  66{
  67        return NULL;
  68}
  69#endif
  70
  71static 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
  80static 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
  89static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
  90{
  91        if (frontswap_enabled)
  92                __frontswap_invalidate_page(type, offset);
  93}
  94
  95static inline void frontswap_invalidate_area(unsigned type)
  96{
  97        if (frontswap_enabled)
  98                __frontswap_invalidate_area(type);
  99}
 100
 101static 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 */
 108