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 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, int nr); 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 folio *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 84 /* 85 * Return the count of contiguous swap entries that share the same 86 * zeromap status as the starting entry. If is_zeromap is not NULL, 87 * it will return the zeromap status of the starting entry. 88 */ 89 static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr, 90 bool *is_zeromap) 91 { 92 struct swap_info_struct *sis = swp_swap_info(entry); 93 unsigned long start = swp_offset(entry); 94 unsigned long end = start + max_nr; 95 bool first_bit; 96 97 first_bit = test_bit(start, sis->zeromap); 98 if (is_zeromap) 99 *is_zeromap = first_bit; 100 101 if (max_nr <= 1) 102 return max_nr; 103 if (first_bit) 104 return find_next_zero_bit(sis->zeromap, end, start) - start; 105 else 106 return find_next_bit(sis->zeromap, end, start) - start; 107 } 108 109 #else /* CONFIG_SWAP */ 110 struct swap_iocb; 111 static inline void swap_read_folio(struct folio *folio, struct swap_iocb **plug) 112 { 113 } 114 static inline void swap_write_unplug(struct swap_iocb *sio) 115 { 116 } 117 118 static inline struct address_space *swap_address_space(swp_entry_t entry) 119 { 120 return NULL; 121 } 122 123 static inline pgoff_t swap_cache_index(swp_entry_t entry) 124 { 125 return 0; 126 } 127 128 static inline void show_swap_cache_info(void) 129 { 130 } 131 132 static inline struct folio *swap_cluster_readahead(swp_entry_t entry, 133 gfp_t gfp_mask, struct mempolicy *mpol, pgoff_t ilx) 134 { 135 return NULL; 136 } 137 138 static inline struct folio *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 139 struct vm_fault *vmf) 140 { 141 return NULL; 142 } 143 144 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 145 { 146 return 0; 147 } 148 149 static inline void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr) 150 { 151 } 152 153 static inline struct folio *swap_cache_get_folio(swp_entry_t entry, 154 struct vm_area_struct *vma, unsigned long addr) 155 { 156 return NULL; 157 } 158 159 static inline 160 struct folio *filemap_get_incore_folio(struct address_space *mapping, 161 pgoff_t index) 162 { 163 return filemap_get_folio(mapping, index); 164 } 165 166 static inline void *get_shadow_from_swap_cache(swp_entry_t entry) 167 { 168 return NULL; 169 } 170 171 static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry, 172 gfp_t gfp_mask, void **shadowp) 173 { 174 return -1; 175 } 176 177 static inline void __delete_from_swap_cache(struct folio *folio, 178 swp_entry_t entry, void *shadow) 179 { 180 } 181 182 static inline void delete_from_swap_cache(struct folio *folio) 183 { 184 } 185 186 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin, 187 unsigned long end) 188 { 189 } 190 191 static inline unsigned int folio_swap_flags(struct folio *folio) 192 { 193 return 0; 194 } 195 196 static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr, 197 bool *has_zeromap) 198 { 199 return 0; 200 } 201 202 #endif /* CONFIG_SWAP */ 203 204 #endif /* _MM_SWAP_H */ 205