1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _MM_SWAP_H 3 #define _MM_SWAP_H 4 5 struct mempolicy; 6 extern int page_cluster; 7 8 #ifdef CONFIG_SWAP 9 #include <linux/swapops.h> /* for swp_offset */ 10 #include <linux/blk_types.h> /* for bio_end_io_t */ 11 12 /* linux/mm/page_io.c */ 13 int sio_pool_init(void); 14 struct swap_iocb; 15 void swap_read_folio(struct folio *folio, struct swap_iocb **plug); 16 void __swap_read_unplug(struct swap_iocb *plug); 17 static inline void swap_read_unplug(struct swap_iocb *plug) 18 { 19 if (unlikely(plug)) 20 __swap_read_unplug(plug); 21 } 22 void swap_write_unplug(struct swap_iocb *sio); 23 int swap_writepage(struct page *page, struct writeback_control *wbc); 24 void __swap_writepage(struct folio *folio, struct writeback_control *wbc); 25 26 /* linux/mm/swap_state.c */ 27 /* One swap address space for each 64M swap space */ 28 #define SWAP_ADDRESS_SPACE_SHIFT 14 29 #define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT) 30 #define SWAP_ADDRESS_SPACE_MASK (SWAP_ADDRESS_SPACE_PAGES - 1) 31 extern struct address_space *swapper_spaces[]; 32 #define swap_address_space(entry) \ 33 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \ 34 >> SWAP_ADDRESS_SPACE_SHIFT]) 35 36 /* 37 * Return the swap device position of the swap entry. 38 */ 39 static inline loff_t swap_dev_pos(swp_entry_t entry) 40 { 41 return ((loff_t)swp_offset(entry)) << PAGE_SHIFT; 42 } 43 44 /* 45 * Return the swap cache index of the swap entry. 46 */ 47 static inline pgoff_t swap_cache_index(swp_entry_t entry) 48 { 49 BUILD_BUG_ON((SWP_OFFSET_MASK | SWAP_ADDRESS_SPACE_MASK) != SWP_OFFSET_MASK); 50 return swp_offset(entry) & SWAP_ADDRESS_SPACE_MASK; 51 } 52 53 void show_swap_cache_info(void); 54 bool add_to_swap(struct folio *folio); 55 void *get_shadow_from_swap_cache(swp_entry_t entry); 56 int add_to_swap_cache(struct folio *folio, swp_entry_t entry, 57 gfp_t gfp, void **shadowp); 58 void __delete_from_swap_cache(struct folio *folio, 59 swp_entry_t entry, void *shadow); 60 void delete_from_swap_cache(struct folio *folio); 61 void clear_shadow_from_swap_cache(int type, unsigned long begin, 62 unsigned long end); 63 void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr); 64 struct folio *swap_cache_get_folio(swp_entry_t entry, 65 struct vm_area_struct *vma, unsigned long addr); 66 struct folio *filemap_get_incore_folio(struct address_space *mapping, 67 pgoff_t index); 68 69 struct folio *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, 70 struct vm_area_struct *vma, unsigned long addr, 71 struct swap_iocb **plug); 72 struct folio *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_flags, 73 struct mempolicy *mpol, pgoff_t ilx, bool *new_page_allocated, 74 bool skip_if_exists); 75 struct folio *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, 76 struct mempolicy *mpol, pgoff_t ilx); 77 struct folio *swapin_readahead(swp_entry_t entry, gfp_t flag, 78 struct vm_fault *vmf); 79 80 static inline unsigned int folio_swap_flags(struct folio *folio) 81 { 82 return swp_swap_info(folio->swap)->flags; 83 } 84 85 /* 86 * Return the count of contiguous swap entries that share the same 87 * zeromap status as the starting entry. If is_zeromap is not NULL, 88 * it will return the zeromap status of the starting entry. 89 */ 90 static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr, 91 bool *is_zeromap) 92 { 93 struct swap_info_struct *sis = swp_swap_info(entry); 94 unsigned long start = swp_offset(entry); 95 unsigned long end = start + max_nr; 96 bool first_bit; 97 98 first_bit = test_bit(start, sis->zeromap); 99 if (is_zeromap) 100 *is_zeromap = first_bit; 101 102 if (max_nr <= 1) 103 return max_nr; 104 if (first_bit) 105 return find_next_zero_bit(sis->zeromap, end, start) - start; 106 else 107 return find_next_bit(sis->zeromap, end, start) - start; 108 } 109 110 #else /* CONFIG_SWAP */ 111 struct swap_iocb; 112 static inline void swap_read_folio(struct folio *folio, struct swap_iocb **plug) 113 { 114 } 115 static inline void swap_write_unplug(struct swap_iocb *sio) 116 { 117 } 118 119 static inline struct address_space *swap_address_space(swp_entry_t entry) 120 { 121 return NULL; 122 } 123 124 static inline pgoff_t swap_cache_index(swp_entry_t entry) 125 { 126 return 0; 127 } 128 129 static inline void show_swap_cache_info(void) 130 { 131 } 132 133 static inline struct folio *swap_cluster_readahead(swp_entry_t entry, 134 gfp_t gfp_mask, struct mempolicy *mpol, pgoff_t ilx) 135 { 136 return NULL; 137 } 138 139 static inline struct folio *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 140 struct vm_fault *vmf) 141 { 142 return NULL; 143 } 144 145 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 146 { 147 return 0; 148 } 149 150 static inline void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr) 151 { 152 } 153 154 static inline struct folio *swap_cache_get_folio(swp_entry_t entry, 155 struct vm_area_struct *vma, unsigned long addr) 156 { 157 return NULL; 158 } 159 160 static inline 161 struct folio *filemap_get_incore_folio(struct address_space *mapping, 162 pgoff_t index) 163 { 164 return filemap_get_folio(mapping, index); 165 } 166 167 static inline bool add_to_swap(struct folio *folio) 168 { 169 return false; 170 } 171 172 static inline void *get_shadow_from_swap_cache(swp_entry_t entry) 173 { 174 return NULL; 175 } 176 177 static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry, 178 gfp_t gfp_mask, void **shadowp) 179 { 180 return -1; 181 } 182 183 static inline void __delete_from_swap_cache(struct folio *folio, 184 swp_entry_t entry, void *shadow) 185 { 186 } 187 188 static inline void delete_from_swap_cache(struct folio *folio) 189 { 190 } 191 192 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin, 193 unsigned long end) 194 { 195 } 196 197 static inline unsigned int folio_swap_flags(struct folio *folio) 198 { 199 return 0; 200 } 201 202 static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr, 203 bool *has_zeromap) 204 { 205 return 0; 206 } 207 208 #endif /* CONFIG_SWAP */ 209 210 #endif /* _MM_SWAP_H */ 211