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);
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 */
swap_dev_pos(swp_entry_t entry)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 */
swap_cache_index(swp_entry_t entry)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, 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
folio_swap_flags(struct folio * folio)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 */
swap_zeromap_batch(swp_entry_t entry,int max_nr,bool * is_zeromap)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;
swap_read_folio(struct folio * folio,struct swap_iocb ** plug)111 static inline void swap_read_folio(struct folio *folio, struct swap_iocb **plug)
112 {
113 }
swap_write_unplug(struct swap_iocb * sio)114 static inline void swap_write_unplug(struct swap_iocb *sio)
115 {
116 }
117
swap_address_space(swp_entry_t entry)118 static inline struct address_space *swap_address_space(swp_entry_t entry)
119 {
120 return NULL;
121 }
122
swap_cache_index(swp_entry_t entry)123 static inline pgoff_t swap_cache_index(swp_entry_t entry)
124 {
125 return 0;
126 }
127
show_swap_cache_info(void)128 static inline void show_swap_cache_info(void)
129 {
130 }
131
swap_cluster_readahead(swp_entry_t entry,gfp_t gfp_mask,struct mempolicy * mpol,pgoff_t ilx)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
swapin_readahead(swp_entry_t swp,gfp_t gfp_mask,struct vm_fault * vmf)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
swap_writepage(struct page * p,struct writeback_control * wbc)144 static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
145 {
146 return 0;
147 }
148
swapcache_clear(struct swap_info_struct * si,swp_entry_t entry,int nr)149 static inline void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr)
150 {
151 }
152
swap_cache_get_folio(swp_entry_t entry,struct vm_area_struct * vma,unsigned long addr)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
filemap_get_incore_folio(struct address_space * mapping,pgoff_t index)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
add_to_swap(struct folio * folio)166 static inline bool add_to_swap(struct folio *folio)
167 {
168 return false;
169 }
170
get_shadow_from_swap_cache(swp_entry_t entry)171 static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
172 {
173 return NULL;
174 }
175
add_to_swap_cache(struct folio * folio,swp_entry_t entry,gfp_t gfp_mask,void ** shadowp)176 static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
177 gfp_t gfp_mask, void **shadowp)
178 {
179 return -1;
180 }
181
__delete_from_swap_cache(struct folio * folio,swp_entry_t entry,void * shadow)182 static inline void __delete_from_swap_cache(struct folio *folio,
183 swp_entry_t entry, void *shadow)
184 {
185 }
186
delete_from_swap_cache(struct folio * folio)187 static inline void delete_from_swap_cache(struct folio *folio)
188 {
189 }
190
clear_shadow_from_swap_cache(int type,unsigned long begin,unsigned long end)191 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
192 unsigned long end)
193 {
194 }
195
folio_swap_flags(struct folio * folio)196 static inline unsigned int folio_swap_flags(struct folio *folio)
197 {
198 return 0;
199 }
200
swap_zeromap_batch(swp_entry_t entry,int max_nr,bool * has_zeromap)201 static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr,
202 bool *has_zeromap)
203 {
204 return 0;
205 }
206
207 #endif /* CONFIG_SWAP */
208
209 #endif /* _MM_SWAP_H */
210