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