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