1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _MM_SWAP_H 3 #define _MM_SWAP_H 4 5 struct mempolicy; 6 struct swap_iocb; 7 8 extern int page_cluster; 9 10 #ifdef CONFIG_SWAP 11 #include <linux/swapops.h> /* for swp_offset */ 12 #include <linux/blk_types.h> /* for bio_end_io_t */ 13 14 /* linux/mm/page_io.c */ 15 int sio_pool_init(void); 16 struct swap_iocb; 17 void swap_read_folio(struct folio *folio, struct swap_iocb **plug); 18 void __swap_read_unplug(struct swap_iocb *plug); 19 static inline void swap_read_unplug(struct swap_iocb *plug) 20 { 21 if (unlikely(plug)) 22 __swap_read_unplug(plug); 23 } 24 void swap_write_unplug(struct swap_iocb *sio); 25 int swap_writeout(struct folio *folio, struct swap_iocb **swap_plug); 26 void __swap_writepage(struct folio *folio, struct swap_iocb **swap_plug); 27 28 /* linux/mm/swap_state.c */ 29 /* One swap address space for each 64M swap space */ 30 #define SWAP_ADDRESS_SPACE_SHIFT 14 31 #define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT) 32 #define SWAP_ADDRESS_SPACE_MASK (SWAP_ADDRESS_SPACE_PAGES - 1) 33 extern struct address_space *swapper_spaces[]; 34 #define swap_address_space(entry) \ 35 (&swapper_spaces[swp_type(entry)][swp_offset(entry) \ 36 >> SWAP_ADDRESS_SPACE_SHIFT]) 37 38 /* 39 * Return the swap device position of the swap entry. 40 */ 41 static inline loff_t swap_dev_pos(swp_entry_t entry) 42 { 43 return ((loff_t)swp_offset(entry)) << PAGE_SHIFT; 44 } 45 46 /* 47 * Return the swap cache index of the swap entry. 48 */ 49 static inline pgoff_t swap_cache_index(swp_entry_t entry) 50 { 51 BUILD_BUG_ON((SWP_OFFSET_MASK | SWAP_ADDRESS_SPACE_MASK) != SWP_OFFSET_MASK); 52 return swp_offset(entry) & SWAP_ADDRESS_SPACE_MASK; 53 } 54 55 void show_swap_cache_info(void); 56 void *get_shadow_from_swap_cache(swp_entry_t entry); 57 int add_to_swap_cache(struct folio *folio, swp_entry_t entry, 58 gfp_t gfp, void **shadowp); 59 void __delete_from_swap_cache(struct folio *folio, 60 swp_entry_t entry, void *shadow); 61 void delete_from_swap_cache(struct folio *folio); 62 void clear_shadow_from_swap_cache(int type, unsigned long begin, 63 unsigned long end); 64 void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr); 65 struct folio *swap_cache_get_folio(swp_entry_t entry, 66 struct vm_area_struct *vma, unsigned long addr); 67 struct folio *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask, 68 struct vm_area_struct *vma, unsigned long addr, 69 struct swap_iocb **plug); 70 struct folio *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_flags, 71 struct mempolicy *mpol, pgoff_t ilx, bool *new_page_allocated, 72 bool skip_if_exists); 73 struct folio *swap_cluster_readahead(swp_entry_t entry, gfp_t flag, 74 struct mempolicy *mpol, pgoff_t ilx); 75 struct folio *swapin_readahead(swp_entry_t entry, gfp_t flag, 76 struct vm_fault *vmf); 77 78 static inline unsigned int folio_swap_flags(struct folio *folio) 79 { 80 return swp_swap_info(folio->swap)->flags; 81 } 82 83 /* 84 * Return the count of contiguous swap entries that share the same 85 * zeromap status as the starting entry. If is_zeromap is not NULL, 86 * it will return the zeromap status of the starting entry. 87 */ 88 static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr, 89 bool *is_zeromap) 90 { 91 struct swap_info_struct *sis = swp_swap_info(entry); 92 unsigned long start = swp_offset(entry); 93 unsigned long end = start + max_nr; 94 bool first_bit; 95 96 first_bit = test_bit(start, sis->zeromap); 97 if (is_zeromap) 98 *is_zeromap = first_bit; 99 100 if (max_nr <= 1) 101 return max_nr; 102 if (first_bit) 103 return find_next_zero_bit(sis->zeromap, end, start) - start; 104 else 105 return find_next_bit(sis->zeromap, end, start) - start; 106 } 107 108 static inline int non_swapcache_batch(swp_entry_t entry, int max_nr) 109 { 110 struct swap_info_struct *si = swp_swap_info(entry); 111 pgoff_t offset = swp_offset(entry); 112 int i; 113 114 /* 115 * While allocating a large folio and doing mTHP swapin, we need to 116 * ensure all entries are not cached, otherwise, the mTHP folio will 117 * be in conflict with the folio in swap cache. 118 */ 119 for (i = 0; i < max_nr; i++) { 120 if ((si->swap_map[offset + i] & SWAP_HAS_CACHE)) 121 return i; 122 } 123 124 return i; 125 } 126 127 #else /* CONFIG_SWAP */ 128 struct swap_iocb; 129 static inline void swap_read_folio(struct folio *folio, struct swap_iocb **plug) 130 { 131 } 132 static inline void swap_write_unplug(struct swap_iocb *sio) 133 { 134 } 135 136 static inline struct address_space *swap_address_space(swp_entry_t entry) 137 { 138 return NULL; 139 } 140 141 static inline pgoff_t swap_cache_index(swp_entry_t entry) 142 { 143 return 0; 144 } 145 146 static inline void show_swap_cache_info(void) 147 { 148 } 149 150 static inline struct folio *swap_cluster_readahead(swp_entry_t entry, 151 gfp_t gfp_mask, struct mempolicy *mpol, pgoff_t ilx) 152 { 153 return NULL; 154 } 155 156 static inline struct folio *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 157 struct vm_fault *vmf) 158 { 159 return NULL; 160 } 161 162 static inline int swap_writeout(struct folio *folio, 163 struct swap_iocb **swap_plug) 164 { 165 return 0; 166 } 167 168 static inline void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr) 169 { 170 } 171 172 static inline struct folio *swap_cache_get_folio(swp_entry_t entry, 173 struct vm_area_struct *vma, unsigned long addr) 174 { 175 return NULL; 176 } 177 178 static inline void *get_shadow_from_swap_cache(swp_entry_t entry) 179 { 180 return NULL; 181 } 182 183 static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry, 184 gfp_t gfp_mask, void **shadowp) 185 { 186 return -1; 187 } 188 189 static inline void __delete_from_swap_cache(struct folio *folio, 190 swp_entry_t entry, void *shadow) 191 { 192 } 193 194 static inline void delete_from_swap_cache(struct folio *folio) 195 { 196 } 197 198 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin, 199 unsigned long end) 200 { 201 } 202 203 static inline unsigned int folio_swap_flags(struct folio *folio) 204 { 205 return 0; 206 } 207 208 static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr, 209 bool *has_zeromap) 210 { 211 return 0; 212 } 213 214 static inline int non_swapcache_batch(swp_entry_t entry, int max_nr) 215 { 216 return 0; 217 } 218 #endif /* CONFIG_SWAP */ 219 220 /** 221 * folio_index - File index of a folio. 222 * @folio: The folio. 223 * 224 * For a folio which is either in the page cache or the swap cache, 225 * return its index within the address_space it belongs to. If you know 226 * the folio is definitely in the page cache, you can look at the folio's 227 * index directly. 228 * 229 * Return: The index (offset in units of pages) of a folio in its file. 230 */ 231 static inline pgoff_t folio_index(struct folio *folio) 232 { 233 if (unlikely(folio_test_swapcache(folio))) 234 return swap_cache_index(folio->swap); 235 return folio->index; 236 } 237 238 #endif /* _MM_SWAP_H */ 239