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#include <linux/jump_label.h>
   8
   9struct frontswap_ops {
  10        void (*init)(unsigned); /* this swap type was just swapon'ed */
  11        int (*store)(unsigned, pgoff_t, struct page *); /* store a page */
  12        int (*load)(unsigned, pgoff_t, struct page *); /* load a page */
  13        void (*invalidate_page)(unsigned, pgoff_t); /* page no longer needed */
  14        void (*invalidate_area)(unsigned); /* swap type just swapoff'ed */
  15        struct frontswap_ops *next; /* private pointer to next ops */
  16};
  17
  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
  33extern struct static_key_false frontswap_enabled_key;
  34
  35static inline bool frontswap_enabled(void)
  36{
  37        return static_branch_unlikely(&frontswap_enabled_key);
  38}
  39
  40static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  41{
  42        return __frontswap_test(sis, offset);
  43}
  44
  45static inline void frontswap_map_set(struct swap_info_struct *p,
  46                                     unsigned long *map)
  47{
  48        p->frontswap_map = map;
  49}
  50
  51static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  52{
  53        return p->frontswap_map;
  54}
  55#else
  56/* all inline routines become no-ops and all externs are ignored */
  57
  58static inline bool frontswap_enabled(void)
  59{
  60        return false;
  61}
  62
  63static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  64{
  65        return false;
  66}
  67
  68static inline void frontswap_map_set(struct swap_info_struct *p,
  69                                     unsigned long *map)
  70{
  71}
  72
  73static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  74{
  75        return NULL;
  76}
  77#endif
  78
  79static inline int frontswap_store(struct page *page)
  80{
  81        if (frontswap_enabled())
  82                return __frontswap_store(page);
  83
  84        return -1;
  85}
  86
  87static inline int frontswap_load(struct page *page)
  88{
  89        if (frontswap_enabled())
  90                return __frontswap_load(page);
  91
  92        return -1;
  93}
  94
  95static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
  96{
  97        if (frontswap_enabled())
  98                __frontswap_invalidate_page(type, offset);
  99}
 100
 101static inline void frontswap_invalidate_area(unsigned type)
 102{
 103        if (frontswap_enabled())
 104                __frontswap_invalidate_area(type);
 105}
 106
 107static inline void frontswap_init(unsigned type, unsigned long *map)
 108{
 109#ifdef CONFIG_FRONTSWAP
 110        __frontswap_init(type, map);
 111#endif
 112}
 113
 114#endif /* _LINUX_FRONTSWAP_H */
 115