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
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