include/linux/frontswap.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _LINUX_FRONTSWAP_H
   3 #define _LINUX_FRONTSWAP_H
   4
   5 #include <linux/swap.h>
   6 #include <linux/mm.h>
   7 #include <linux/bitops.h>
   8 #include <linux/jump_label.h>
   9
  10 struct frontswap_ops {
  11         void (*init)(unsigned); /* this swap type was just swapon'ed */
  12         int (*store)(unsigned, pgoff_t, struct page *); /* store a page */
  13         int (*load)(unsigned, pgoff_t, struct page *); /* load a page */
  14         void (*invalidate_page)(unsigned, pgoff_t); /* page no longer needed */
  15         void (*invalidate_area)(unsigned); /* swap type just swapoff'ed */
  16         struct frontswap_ops *next; /* private pointer to next ops */
  17 };
  18
  19 extern void frontswap_register_ops(struct frontswap_ops *ops);
  20 extern void frontswap_shrink(unsigned long);
  21 extern unsigned long frontswap_curr_pages(void);
  22 extern void frontswap_writethrough(bool);
  23 #define FRONTSWAP_HAS_EXCLUSIVE_GETS
  24 extern void frontswap_tmem_exclusive_gets(bool);
  25
  26 extern bool __frontswap_test(struct swap_info_struct *, pgoff_t);
  27 extern void __frontswap_init(unsigned type, unsigned long *map);
  28 extern int __frontswap_store(struct page *page);
  29 extern int __frontswap_load(struct page *page);
  30 extern void __frontswap_invalidate_page(unsigned, pgoff_t);
  31 extern void __frontswap_invalidate_area(unsigned);
  32
  33 #ifdef CONFIG_FRONTSWAP
  34 extern struct static_key_false frontswap_enabled_key;
  35
  36 static inline bool frontswap_enabled(void)
  37 {
  38         return static_branch_unlikely(&frontswap_enabled_key);
  39 }
  40
  41 static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  42 {
  43         return __frontswap_test(sis, offset);
  44 }
  45
  46 static inline void frontswap_map_set(struct swap_info_struct *p,
  47                                      unsigned long *map)
  48 {
  49         p->frontswap_map = map;
  50 }
  51
  52 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  53 {
  54         return p->frontswap_map;
  55 }
  56 #else
  57 /* all inline routines become no-ops and all externs are ignored */
  58
  59 static inline bool frontswap_enabled(void)
  60 {
  61         return false;
  62 }
  63
  64 static inline bool frontswap_test(struct swap_info_struct *sis, pgoff_t offset)
  65 {
  66         return false;
  67 }
  68
  69 static inline void frontswap_map_set(struct swap_info_struct *p,
  70                                      unsigned long *map)
  71 {
  72 }
  73
  74 static inline unsigned long *frontswap_map_get(struct swap_info_struct *p)
  75 {
  76         return NULL;
  77 }
  78 #endif
  79
  80 static inline int frontswap_store(struct page *page)
  81 {
  82         if (frontswap_enabled())
  83                 return __frontswap_store(page);
  84
  85         return -1;
  86 }
  87
  88 static inline int frontswap_load(struct page *page)
  89 {
  90         if (frontswap_enabled())
  91                 return __frontswap_load(page);
  92
  93         return -1;
  94 }
  95
  96 static inline void frontswap_invalidate_page(unsigned type, pgoff_t offset)
  97 {
  98         if (frontswap_enabled())
  99                 __frontswap_invalidate_page(type, offset);
 100 }
 101
 102 static inline void frontswap_invalidate_area(unsigned type)
 103 {
 104         if (frontswap_enabled())
 105                 __frontswap_invalidate_area(type);
 106 }
 107
 108 static inline void frontswap_init(unsigned type, unsigned long *map)
 109 {
 110 #ifdef CONFIG_FRONTSWAP
 111         __frontswap_init(type, map);
 112 #endif
 113 }
 114
 115 #endif /* _LINUX_FRONTSWAP_H */