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, bool do_poll, 15 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); 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 page *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 #else /* CONFIG_SWAP */ 85 struct swap_iocb; 86 static inline void swap_read_folio(struct folio *folio, bool do_poll, 87 struct swap_iocb **plug) 88 { 89 } 90 static inline void swap_write_unplug(struct swap_iocb *sio) 91 { 92 } 93 94 static inline struct address_space *swap_address_space(swp_entry_t entry) 95 { 96 return NULL; 97 } 98 99 static inline pgoff_t swap_cache_index(swp_entry_t entry) 100 { 101 return 0; 102 } 103 104 static inline void show_swap_cache_info(void) 105 { 106 } 107 108 static inline struct folio *swap_cluster_readahead(swp_entry_t entry, 109 gfp_t gfp_mask, struct mempolicy *mpol, pgoff_t ilx) 110 { 111 return NULL; 112 } 113 114 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask, 115 struct vm_fault *vmf) 116 { 117 return NULL; 118 } 119 120 static inline int swap_writepage(struct page *p, struct writeback_control *wbc) 121 { 122 return 0; 123 } 124 125 static inline void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry) 126 { 127 } 128 129 static inline struct folio *swap_cache_get_folio(swp_entry_t entry, 130 struct vm_area_struct *vma, unsigned long addr) 131 { 132 return NULL; 133 } 134 135 static inline 136 struct folio *filemap_get_incore_folio(struct address_space *mapping, 137 pgoff_t index) 138 { 139 return filemap_get_folio(mapping, index); 140 } 141 142 static inline bool add_to_swap(struct folio *folio) 143 { 144 return false; 145 } 146 147 static inline void *get_shadow_from_swap_cache(swp_entry_t entry) 148 { 149 return NULL; 150 } 151 152 static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry, 153 gfp_t gfp_mask, void **shadowp) 154 { 155 return -1; 156 } 157 158 static inline void __delete_from_swap_cache(struct folio *folio, 159 swp_entry_t entry, void *shadow) 160 { 161 } 162 163 static inline void delete_from_swap_cache(struct folio *folio) 164 { 165 } 166 167 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin, 168 unsigned long end) 169 { 170 } 171 172 static inline unsigned int folio_swap_flags(struct folio *folio) 173 { 174 return 0; 175 } 176 #endif /* CONFIG_SWAP */ 177 #endif /* _MM_SWAP_H */ 178