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 int __swap_writepage(struct page *page, struct writeback_control *wbc);
22 
23 /* linux/mm/swap_state.c */
24 /* One swap address space for each 64M swap space */
25 #define SWAP_ADDRESS_SPACE_SHIFT	14
26 #define SWAP_ADDRESS_SPACE_PAGES	(1 << SWAP_ADDRESS_SPACE_SHIFT)
27 extern struct address_space *swapper_spaces[];
28 #define swap_address_space(entry)			    \
29 	(&swapper_spaces[swp_type(entry)][swp_offset(entry) \
30 		>> SWAP_ADDRESS_SPACE_SHIFT])
31 
32 void show_swap_cache_info(void);
33 bool add_to_swap(struct folio *folio);
34 void *get_shadow_from_swap_cache(swp_entry_t entry);
35 int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
36 		      gfp_t gfp, void **shadowp);
37 void __delete_from_swap_cache(struct folio *folio,
38 			      swp_entry_t entry, void *shadow);
39 void delete_from_swap_cache(struct folio *folio);
40 void clear_shadow_from_swap_cache(int type, unsigned long begin,
41 				  unsigned long end);
42 struct folio *swap_cache_get_folio(swp_entry_t entry,
43 		struct vm_area_struct *vma, unsigned long addr);
44 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index);
45 
46 struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
47 				   struct vm_area_struct *vma,
48 				   unsigned long addr,
49 				   bool do_poll,
50 				   struct swap_iocb **plug);
51 struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
52 				     struct vm_area_struct *vma,
53 				     unsigned long addr,
54 				     bool *new_page_allocated);
55 struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
56 				    struct vm_fault *vmf);
57 struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
58 			      struct vm_fault *vmf);
59 
folio_swap_flags(struct folio * folio)60 static inline unsigned int folio_swap_flags(struct folio *folio)
61 {
62 	return page_swap_info(&folio->page)->flags;
63 }
64 #else /* CONFIG_SWAP */
65 struct swap_iocb;
swap_readpage(struct page * page,bool do_poll,struct swap_iocb ** plug)66 static inline int swap_readpage(struct page *page, bool do_poll,
67 				struct swap_iocb **plug)
68 {
69 	return 0;
70 }
swap_write_unplug(struct swap_iocb * sio)71 static inline void swap_write_unplug(struct swap_iocb *sio)
72 {
73 }
74 
swap_address_space(swp_entry_t entry)75 static inline struct address_space *swap_address_space(swp_entry_t entry)
76 {
77 	return NULL;
78 }
79 
show_swap_cache_info(void)80 static inline void show_swap_cache_info(void)
81 {
82 }
83 
swap_cluster_readahead(swp_entry_t entry,gfp_t gfp_mask,struct vm_fault * vmf)84 static inline struct page *swap_cluster_readahead(swp_entry_t entry,
85 				gfp_t gfp_mask, struct vm_fault *vmf)
86 {
87 	return NULL;
88 }
89 
swapin_readahead(swp_entry_t swp,gfp_t gfp_mask,struct vm_fault * vmf)90 static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
91 			struct vm_fault *vmf)
92 {
93 	return NULL;
94 }
95 
swap_writepage(struct page * p,struct writeback_control * wbc)96 static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
97 {
98 	return 0;
99 }
100 
swap_cache_get_folio(swp_entry_t entry,struct vm_area_struct * vma,unsigned long addr)101 static inline struct folio *swap_cache_get_folio(swp_entry_t entry,
102 		struct vm_area_struct *vma, unsigned long addr)
103 {
104 	return NULL;
105 }
106 
107 static inline
find_get_incore_page(struct address_space * mapping,pgoff_t index)108 struct page *find_get_incore_page(struct address_space *mapping, pgoff_t index)
109 {
110 	return find_get_page(mapping, index);
111 }
112 
add_to_swap(struct folio * folio)113 static inline bool add_to_swap(struct folio *folio)
114 {
115 	return false;
116 }
117 
get_shadow_from_swap_cache(swp_entry_t entry)118 static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
119 {
120 	return NULL;
121 }
122 
add_to_swap_cache(struct folio * folio,swp_entry_t entry,gfp_t gfp_mask,void ** shadowp)123 static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
124 					gfp_t gfp_mask, void **shadowp)
125 {
126 	return -1;
127 }
128 
__delete_from_swap_cache(struct folio * folio,swp_entry_t entry,void * shadow)129 static inline void __delete_from_swap_cache(struct folio *folio,
130 					swp_entry_t entry, void *shadow)
131 {
132 }
133 
delete_from_swap_cache(struct folio * folio)134 static inline void delete_from_swap_cache(struct folio *folio)
135 {
136 }
137 
clear_shadow_from_swap_cache(int type,unsigned long begin,unsigned long end)138 static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
139 				unsigned long end)
140 {
141 }
142 
folio_swap_flags(struct folio * folio)143 static inline unsigned int folio_swap_flags(struct folio *folio)
144 {
145 	return 0;
146 }
147 #endif /* CONFIG_SWAP */
148 #endif /* _MM_SWAP_H */
149