mm/swap.h

   1 /* SPDX-License-Identifier: GPL-2.0 */
   2 #ifndef _MM_SWAP_H
   3 #define _MM_SWAP_H
   4
   5 struct mempolicy;
   6
   7 #ifdef CONFIG_SWAP
   8 #include <linux/swapops.h> /* for swp_offset */
   9 #include <linux/blk_types.h> /* for bio_end_io_t */
  10
  11 /* linux/mm/page_io.c */
  12 int sio_pool_init(void);
  13 struct swap_iocb;
  14 void swap_read_folio(struct folio *folio, struct swap_iocb **plug);
  15 void __swap_read_unplug(struct swap_iocb *plug);
  16 static inline void swap_read_unplug(struct swap_iocb *plug)
  17 {
  18         if (unlikely(plug))
  19                 __swap_read_unplug(plug);
  20 }
  21 void swap_write_unplug(struct swap_iocb *sio);
  22 int swap_writepage(struct page *page, struct writeback_control *wbc);
  23 void __swap_writepage(struct folio *folio, struct writeback_control *wbc);
  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 #define SWAP_ADDRESS_SPACE_MASK         (SWAP_ADDRESS_SPACE_PAGES - 1)
  30 extern struct address_space *swapper_spaces[];
  31 #define swap_address_space(entry)                           \
  32         (&swapper_spaces[swp_type(entry)][swp_offset(entry) \
  33                 >> SWAP_ADDRESS_SPACE_SHIFT])
  34
  35 /*
  36  * Return the swap device position of the swap entry.
  37  */
  38 static inline loff_t swap_dev_pos(swp_entry_t entry)
  39 {
  40         return ((loff_t)swp_offset(entry)) << PAGE_SHIFT;
  41 }
  42
  43 /*
  44  * Return the swap cache index of the swap entry.
  45  */
  46 static inline pgoff_t swap_cache_index(swp_entry_t entry)
  47 {
  48         BUILD_BUG_ON((SWP_OFFSET_MASK | SWAP_ADDRESS_SPACE_MASK) != SWP_OFFSET_MASK);
  49         return swp_offset(entry) & SWAP_ADDRESS_SPACE_MASK;
  50 }
  51
  52 void show_swap_cache_info(void);
  53 bool add_to_swap(struct folio *folio);
  54 void *get_shadow_from_swap_cache(swp_entry_t entry);
  55 int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
  56                       gfp_t gfp, void **shadowp);
  57 void __delete_from_swap_cache(struct folio *folio,
  58                               swp_entry_t entry, void *shadow);
  59 void delete_from_swap_cache(struct folio *folio);
  60 void clear_shadow_from_swap_cache(int type, unsigned long begin,
  61                                   unsigned long end);
  62 void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry);
  63 struct folio *swap_cache_get_folio(swp_entry_t entry,
  64                 struct vm_area_struct *vma, unsigned long addr);
  65 struct folio *filemap_get_incore_folio(struct address_space *mapping,
  66                 pgoff_t index);
  67
  68 struct folio *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
  69                 struct vm_area_struct *vma, unsigned long addr,
  70                 struct swap_iocb **plug);
  71 struct folio *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_flags,
  72                 struct mempolicy *mpol, pgoff_t ilx, bool *new_page_allocated,
  73                 bool skip_if_exists);
  74 struct folio *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
  75                 struct mempolicy *mpol, pgoff_t ilx);
  76 struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
  77                               struct vm_fault *vmf);
  78
  79 static inline unsigned int folio_swap_flags(struct folio *folio)
  80 {
  81         return swp_swap_info(folio->swap)->flags;
  82 }
  83 #else /* CONFIG_SWAP */
  84 struct swap_iocb;
  85 static inline void swap_read_folio(struct folio *folio, struct swap_iocb **plug)
  86 {
  87 }
  88 static inline void swap_write_unplug(struct swap_iocb *sio)
  89 {
  90 }
  91
  92 static inline struct address_space *swap_address_space(swp_entry_t entry)
  93 {
  94         return NULL;
  95 }
  96
  97 static inline pgoff_t swap_cache_index(swp_entry_t entry)
  98 {
  99         return 0;
 100 }
 101
 102 static inline void show_swap_cache_info(void)
 103 {
 104 }
 105
 106 static inline struct folio *swap_cluster_readahead(swp_entry_t entry,
 107                         gfp_t gfp_mask, struct mempolicy *mpol, pgoff_t ilx)
 108 {
 109         return NULL;
 110 }
 111
 112 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
 113                         struct vm_fault *vmf)
 114 {
 115         return NULL;
 116 }
 117
 118 static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
 119 {
 120         return 0;
 121 }
 122
 123 static inline void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry)
 124 {
 125 }
 126
 127 static inline struct folio *swap_cache_get_folio(swp_entry_t entry,
 128                 struct vm_area_struct *vma, unsigned long addr)
 129 {
 130         return NULL;
 131 }
 132
 133 static inline
 134 struct folio *filemap_get_incore_folio(struct address_space *mapping,
 135                 pgoff_t index)
 136 {
 137         return filemap_get_folio(mapping, index);
 138 }
 139
 140 static inline bool add_to_swap(struct folio *folio)
 141 {
 142         return false;
 143 }
 144
 145 static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
 146 {
 147         return NULL;
 148 }
 149
 150 static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
 151                                         gfp_t gfp_mask, void **shadowp)
 152 {
 153         return -1;
 154 }
 155
 156 static inline void __delete_from_swap_cache(struct folio *folio,
 157                                         swp_entry_t entry, void *shadow)
 158 {
 159 }
 160
 161 static inline void delete_from_swap_cache(struct folio *folio)
 162 {
 163 }
 164
 165 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
 166                                 unsigned long end)
 167 {
 168 }
 169
 170 static inline unsigned int folio_swap_flags(struct folio *folio)
 171 {
 172         return 0;
 173 }
 174 #endif /* CONFIG_SWAP */
 175 #endif /* _MM_SWAP_H */