1 /* SPDX-License-Identifier: GPL-2.0 */
2 #ifndef _MM_SWAP_H
3 #define _MM_SWAP_H
4 
5 #ifdef CONFIG_SWAP
6 #include <linux/blk_types.h> /* for bio_end_io_t */
7 
8 /* linux/mm/page_io.c */
9 int sio_pool_init(void);
10 struct swap_iocb;
11 int swap_readpage(struct page *page, bool do_poll,
12 		  struct swap_iocb **plug);
13 void __swap_read_unplug(struct swap_iocb *plug);
swap_read_unplug(struct swap_iocb * plug)14 static inline void swap_read_unplug(struct swap_iocb *plug)
15 {
16 	if (unlikely(plug))
17 		__swap_read_unplug(plug);
18 }
19 void swap_write_unplug(struct swap_iocb *sio);
20 int swap_writepage(struct page *page, struct writeback_control *wbc);
21 void end_swap_bio_write(struct bio *bio);
22 int __swap_writepage(struct page *page, struct writeback_control *wbc,
23 		     bio_end_io_t end_write_func);
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 extern struct address_space *swapper_spaces[];
30 #define swap_address_space(entry)			    \
31 	(&swapper_spaces[swp_type(entry)][swp_offset(entry) \
32 		>> SWAP_ADDRESS_SPACE_SHIFT])
33 
34 void show_swap_cache_info(void);
35 bool add_to_swap(struct folio *folio);
36 void *get_shadow_from_swap_cache(swp_entry_t entry);
37 int add_to_swap_cache(struct page *page, swp_entry_t entry,
38 		      gfp_t gfp, void **shadowp);
39 void __delete_from_swap_cache(struct page *page,
40 			      swp_entry_t entry, void *shadow);
41 void delete_from_swap_cache(struct page *page);
42 void clear_shadow_from_swap_cache(int type, unsigned long begin,
43 				  unsigned long end);
44 void free_swap_cache(struct page *page);
45 struct page *lookup_swap_cache(swp_entry_t entry,
46 			       struct vm_area_struct *vma,
47 			       unsigned long addr);
48 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index);
49 
50 struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
51 				   struct vm_area_struct *vma,
52 				   unsigned long addr,
53 				   bool do_poll,
54 				   struct swap_iocb **plug);
55 struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
56 				     struct vm_area_struct *vma,
57 				     unsigned long addr,
58 				     bool *new_page_allocated);
59 struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
60 				    struct vm_fault *vmf);
61 struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
62 			      struct vm_fault *vmf);
63 
page_swap_flags(struct page * page)64 static inline unsigned int page_swap_flags(struct page *page)
65 {
66 	return page_swap_info(page)->flags;
67 }
68 #else /* CONFIG_SWAP */
69 struct swap_iocb;
swap_readpage(struct page * page,bool do_poll,struct swap_iocb ** plug)70 static inline int swap_readpage(struct page *page, bool do_poll,
71 				struct swap_iocb **plug)
72 {
73 	return 0;
74 }
swap_write_unplug(struct swap_iocb * sio)75 static inline void swap_write_unplug(struct swap_iocb *sio)
76 {
77 }
78 
swap_address_space(swp_entry_t entry)79 static inline struct address_space *swap_address_space(swp_entry_t entry)
80 {
81 	return NULL;
82 }
83 
free_swap_cache(struct page * page)84 static inline void free_swap_cache(struct page *page)
85 {
86 }
87 
show_swap_cache_info(void)88 static inline void show_swap_cache_info(void)
89 {
90 }
91 
swap_cluster_readahead(swp_entry_t entry,gfp_t gfp_mask,struct vm_fault * vmf)92 static inline struct page *swap_cluster_readahead(swp_entry_t entry,
93 				gfp_t gfp_mask, struct vm_fault *vmf)
94 {
95 	return NULL;
96 }
97 
swapin_readahead(swp_entry_t swp,gfp_t gfp_mask,struct vm_fault * vmf)98 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
99 			struct vm_fault *vmf)
100 {
101 	return NULL;
102 }
103 
swap_writepage(struct page * p,struct writeback_control * wbc)104 static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
105 {
106 	return 0;
107 }
108 
lookup_swap_cache(swp_entry_t swp,struct vm_area_struct * vma,unsigned long addr)109 static inline struct page *lookup_swap_cache(swp_entry_t swp,
110 					     struct vm_area_struct *vma,
111 					     unsigned long addr)
112 {
113 	return NULL;
114 }
115 
116 static inline
find_get_incore_page(struct address_space * mapping,pgoff_t index)117 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index)
118 {
119 	return find_get_page(mapping, index);
120 }
121 
add_to_swap(struct folio * folio)122 static inline bool add_to_swap(struct folio *folio)
123 {
124 	return false;
125 }
126 
get_shadow_from_swap_cache(swp_entry_t entry)127 static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
128 {
129 	return NULL;
130 }
131 
add_to_swap_cache(struct page * page,swp_entry_t entry,gfp_t gfp_mask,void ** shadowp)132 static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
133 					gfp_t gfp_mask, void **shadowp)
134 {
135 	return -1;
136 }
137 
__delete_from_swap_cache(struct page * page,swp_entry_t entry,void * shadow)138 static inline void __delete_from_swap_cache(struct page *page,
139 					swp_entry_t entry, void *shadow)
140 {
141 }
142 
delete_from_swap_cache(struct page * page)143 static inline void delete_from_swap_cache(struct page *page)
144 {
145 }
146 
clear_shadow_from_swap_cache(int type,unsigned long begin,unsigned long end)147 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
148 				unsigned long end)
149 {
150 }
151 
page_swap_flags(struct page * page)152 static inline unsigned int page_swap_flags(struct page *page)
153 {
154 	return 0;
155 }
156 #endif /* CONFIG_SWAP */
157 #endif /* _MM_SWAP_H */
158