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 void *get_shadow_from_swap_cache(swp_entry_t entry); 54 int add_to_swap_cache(struct folio *folio, swp_entry_t entry, 55 gfp_t gfp, void **shadowp); 56 void __delete_from_swap_cache(struct folio *folio, 57 swp_entry_t entry, void *shadow); 58 void delete_from_swap_cache(struct folio *folio); 59 void clear_shadow_from_swap_cache(int type, unsigned long begin, 60 unsigned long end); 61 void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr); 62 struct folio *swap_cache_get_folio(swp_entry_t entry, 63 struct vm_area_struct *vma, unsigned long addr); 64 struct folio *filemap_get_incore_folio(struct address_space *mapping, 65 pgoff_t index); 66 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 #else /* CONFIG_SWAP */ 109 struct swap_iocb; 110 static inline void swap_read_folio(struct folio *folio, struct swap_iocb **plug) 111 { 112 } 113 static inline void swap_write_unplug(struct swap_iocb *sio) 114 { 115 } 116 117 static inline struct address_space *swap_address_space(swp_entry_t entry) 118 { 119 return NULL; 120 } 121 122 static inline pgoff_t swap_cache_index(swp_entry_t entry) 123 { 124 return 0; 125 } 126 127 static inline void show_swap_cache_info(void) 128 { 129 } 130 131 static inline struct folio *swap_cluster_readahead(swp_entry_t entry, 132 gfp_t gfp_mask, struct mempolicy *mpol, pgoff_t ilx) 133 { 134 return NULL; 135 } 136 137 static inline struct folio *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 138 struct vm_fault *vmf) 139 { 140 return NULL; 141 } 142 143 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 144 { 145 return 0; 146 } 147 148 static inline void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr) 149 { 150 } 151 152 static inline struct folio *swap_cache_get_folio(swp_entry_t entry, 153 struct vm_area_struct *vma, unsigned long addr) 154 { 155 return NULL; 156 } 157 158 static inline 159 struct folio *filemap_get_incore_folio(struct address_space *mapping, 160 pgoff_t index) 161 { 162 return filemap_get_folio(mapping, index); 163 } 164 165 static inline void *get_shadow_from_swap_cache(swp_entry_t entry) 166 { 167 return NULL; 168 } 169 170 static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry, 171 gfp_t gfp_mask, void **shadowp) 172 { 173 return -1; 174 } 175 176 static inline void __delete_from_swap_cache(struct folio *folio, 177 swp_entry_t entry, void *shadow) 178 { 179 } 180 181 static inline void delete_from_swap_cache(struct folio *folio) 182 { 183 } 184 185 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin, 186 unsigned long end) 187 { 188 } 189 190 static inline unsigned int folio_swap_flags(struct folio *folio) 191 { 192 return 0; 193 } 194 195 static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr, 196 bool *has_zeromap) 197 { 198 return 0; 199 } 200 201 #endif /* CONFIG_SWAP */ 202 203 #endif /* _MM_SWAP_H */ 204