mm/swap.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _MM_SWAP_H
   3 #define _MM_SWAP_H
   4
   5 #ifdef CONFIG_SWAP
   6 #include <linux/blk_types.h> /* for bio_end_io_t */
   7
   8 /* linux/mm/page_io.c */
   9 int sio_pool_init(void);
  10 struct swap_iocb;
  11 int swap_readpage(struct page *page, bool do_poll,
  12                   struct swap_iocb **plug);
  13 void __swap_read_unplug(struct swap_iocb *plug);
  14 static inline void swap_read_unplug(struct swap_iocb *plug)
  15 {
  16         if (unlikely(plug))
  17                 __swap_read_unplug(plug);
  18 }
  19 void swap_write_unplug(struct swap_iocb *sio);
  20 int swap_writepage(struct page *page, struct writeback_control *wbc);
  21 void end_swap_bio_write(struct bio *bio);
  22 int __swap_writepage(struct page *page, struct writeback_control *wbc,
  23                      bio_end_io_t end_write_func);
  24
  25 /* linux/mm/swap_state.c */
  26 /* One swap address space for each 64M swap space */
  27 #define SWAP_ADDRESS_SPACE_SHIFT        14
  28 #define SWAP_ADDRESS_SPACE_PAGES        (1 << SWAP_ADDRESS_SPACE_SHIFT)
  29 extern struct address_space *swapper_spaces[];
  30 #define swap_address_space(entry)                           \
  31         (&swapper_spaces[swp_type(entry)][swp_offset(entry) \
  32                 >> SWAP_ADDRESS_SPACE_SHIFT])
  33
  34 void show_swap_cache_info(void);
  35 bool add_to_swap(struct folio *folio);
  36 void *get_shadow_from_swap_cache(swp_entry_t entry);
  37 int add_to_swap_cache(struct page *page, swp_entry_t entry,
  38                       gfp_t gfp, void **shadowp);
  39 void __delete_from_swap_cache(struct page *page,
  40                               swp_entry_t entry, void *shadow);
  41 void delete_from_swap_cache(struct page *page);
  42 void clear_shadow_from_swap_cache(int type, unsigned long begin,
  43                                   unsigned long end);
  44 void free_swap_cache(struct page *page);
  45 struct page *lookup_swap_cache(swp_entry_t entry,
  46                                struct vm_area_struct *vma,
  47                                unsigned long addr);
  48 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index);
  49
  50 struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
  51                                    struct vm_area_struct *vma,
  52                                    unsigned long addr,
  53                                    bool do_poll,
  54                                    struct swap_iocb **plug);
  55 struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
  56                                      struct vm_area_struct *vma,
  57                                      unsigned long addr,
  58                                      bool *new_page_allocated);
  59 struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
  60                                     struct vm_fault *vmf);
  61 struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
  62                               struct vm_fault *vmf);
  63
  64 static inline unsigned int page_swap_flags(struct page *page)
  65 {
  66         return page_swap_info(page)->flags;
  67 }
  68 #else /* CONFIG_SWAP */
  69 struct swap_iocb;
  70 static inline int swap_readpage(struct page *page, bool do_poll,
  71                                 struct swap_iocb **plug)
  72 {
  73         return 0;
  74 }
  75 static inline void swap_write_unplug(struct swap_iocb *sio)
  76 {
  77 }
  78
  79 static inline struct address_space *swap_address_space(swp_entry_t entry)
  80 {
  81         return NULL;
  82 }
  83
  84 static inline void free_swap_cache(struct page *page)
  85 {
  86 }
  87
  88 static inline void show_swap_cache_info(void)
  89 {
  90 }
  91
  92 static inline struct page *swap_cluster_readahead(swp_entry_t entry,
  93                                 gfp_t gfp_mask, struct vm_fault *vmf)
  94 {
  95         return NULL;
  96 }
  97
  98 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
  99                         struct vm_fault *vmf)
 100 {
 101         return NULL;
 102 }
 103
 104 static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
 105 {
 106         return 0;
 107 }
 108
 109 static inline struct page *lookup_swap_cache(swp_entry_t swp,
 110                                              struct vm_area_struct *vma,
 111                                              unsigned long addr)
 112 {
 113         return NULL;
 114 }
 115
 116 static inline
 117 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index)
 118 {
 119         return find_get_page(mapping, index);
 120 }
 121
 122 static inline bool add_to_swap(struct folio *folio)
 123 {
 124         return false;
 125 }
 126
 127 static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
 128 {
 129         return NULL;
 130 }
 131
 132 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
 133                                         gfp_t gfp_mask, void **shadowp)
 134 {
 135         return -1;
 136 }
 137
 138 static inline void __delete_from_swap_cache(struct page *page,
 139                                         swp_entry_t entry, void *shadow)
 140 {
 141 }
 142
 143 static inline void delete_from_swap_cache(struct page *page)
 144 {
 145 }
 146
 147 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
 148                                 unsigned long end)
 149 {
 150 }
 151
 152 static inline unsigned int page_swap_flags(struct page *page)
 153 {
 154         return 0;
 155 }
 156 #endif /* CONFIG_SWAP */
 157 #endif /* _MM_SWAP_H */