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 */ 176