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 folio *folio,
  40                               swp_entry_t entry, void *shadow);
  41 void delete_from_swap_cache(struct folio *folio);
  42 void clear_shadow_from_swap_cache(int type, unsigned long begin,
  43                                   unsigned long end);
  44 struct page *lookup_swap_cache(swp_entry_t entry,
  45                                struct vm_area_struct *vma,
  46                                unsigned long addr);
  47 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index);
  48
  49 struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
  50                                    struct vm_area_struct *vma,
  51                                    unsigned long addr,
  52                                    bool do_poll,
  53                                    struct swap_iocb **plug);
  54 struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
  55                                      struct vm_area_struct *vma,
  56                                      unsigned long addr,
  57                                      bool *new_page_allocated);
  58 struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
  59                                     struct vm_fault *vmf);
  60 struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
  61                               struct vm_fault *vmf);
  62
  63 static inline unsigned int folio_swap_flags(struct folio *folio)
  64 {
  65         return page_swap_info(&folio->page)->flags;
  66 }
  67 #else /* CONFIG_SWAP */
  68 struct swap_iocb;
  69 static inline int swap_readpage(struct page *page, bool do_poll,
  70                                 struct swap_iocb **plug)
  71 {
  72         return 0;
  73 }
  74 static inline void swap_write_unplug(struct swap_iocb *sio)
  75 {
  76 }
  77
  78 static inline struct address_space *swap_address_space(swp_entry_t entry)
  79 {
  80         return NULL;
  81 }
  82
  83 static inline void show_swap_cache_info(void)
  84 {
  85 }
  86
  87 static inline struct page *swap_cluster_readahead(swp_entry_t entry,
  88                                 gfp_t gfp_mask, struct vm_fault *vmf)
  89 {
  90         return NULL;
  91 }
  92
  93 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
  94                         struct vm_fault *vmf)
  95 {
  96         return NULL;
  97 }
  98
  99 static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
 100 {
 101         return 0;
 102 }
 103
 104 static inline struct page *lookup_swap_cache(swp_entry_t swp,
 105                                              struct vm_area_struct *vma,
 106                                              unsigned long addr)
 107 {
 108         return NULL;
 109 }
 110
 111 static inline
 112 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index)
 113 {
 114         return find_get_page(mapping, index);
 115 }
 116
 117 static inline bool add_to_swap(struct folio *folio)
 118 {
 119         return false;
 120 }
 121
 122 static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
 123 {
 124         return NULL;
 125 }
 126
 127 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
 128                                         gfp_t gfp_mask, void **shadowp)
 129 {
 130         return -1;
 131 }
 132
 133 static inline void __delete_from_swap_cache(struct folio *folio,
 134                                         swp_entry_t entry, void *shadow)
 135 {
 136 }
 137
 138 static inline void delete_from_swap_cache(struct folio *folio)
 139 {
 140 }
 141
 142 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
 143                                 unsigned long end)
 144 {
 145 }
 146
 147 static inline unsigned int folio_swap_flags(struct folio *folio)
 148 {
 149         return 0;
 150 }
 151 #endif /* CONFIG_SWAP */
 152 #endif /* _MM_SWAP_H */