1/* SPDX-License-Identifier: GPL-2.0 */
2#ifndef _MM_SWAP_H
3#define _MM_SWAP_H
4
5struct mempolicy;
6
7#ifdef CONFIG_SWAP
8#include <linux/blk_types.h> /* for bio_end_io_t */
9
10/* linux/mm/page_io.c */
11int sio_pool_init(void);
12struct swap_iocb;
13void swap_read_folio(struct folio *folio, bool do_poll,
14		struct swap_iocb **plug);
15void __swap_read_unplug(struct swap_iocb *plug);
16static inline void swap_read_unplug(struct swap_iocb *plug)
17{
18	if (unlikely(plug))
19		__swap_read_unplug(plug);
20}
21void swap_write_unplug(struct swap_iocb *sio);
22int swap_writepage(struct page *page, struct writeback_control *wbc);
23void __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)
29extern 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
34void show_swap_cache_info(void);
35bool add_to_swap(struct folio *folio);
36void *get_shadow_from_swap_cache(swp_entry_t entry);
37int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
38		      gfp_t gfp, void **shadowp);
39void __delete_from_swap_cache(struct folio *folio,
40			      swp_entry_t entry, void *shadow);
41void delete_from_swap_cache(struct folio *folio);
42void clear_shadow_from_swap_cache(int type, unsigned long begin,
43				  unsigned long end);
44void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry);
45struct folio *swap_cache_get_folio(swp_entry_t entry,
46		struct vm_area_struct *vma, unsigned long addr);
47struct folio *filemap_get_incore_folio(struct address_space *mapping,
48		pgoff_t index);
49
50struct folio *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
51		struct vm_area_struct *vma, unsigned long addr,
52		struct swap_iocb **plug);
53struct folio *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_flags,
54		struct mempolicy *mpol, pgoff_t ilx, bool *new_page_allocated,
55		bool skip_if_exists);
56struct folio *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
57		struct mempolicy *mpol, pgoff_t ilx);
58struct page *swapin_readahead(swp_entry_t entry, gfp_t flag,
59			      struct vm_fault *vmf);
60
61static inline unsigned int folio_swap_flags(struct folio *folio)
62{
63	return swp_swap_info(folio->swap)->flags;
64}
65#else /* CONFIG_SWAP */
66struct swap_iocb;
67static inline void swap_read_folio(struct folio *folio, bool do_poll,
68		struct swap_iocb **plug)
69{
70}
71static inline void swap_write_unplug(struct swap_iocb *sio)
72{
73}
74
75static inline struct address_space *swap_address_space(swp_entry_t entry)
76{
77	return NULL;
78}
79
80static inline void show_swap_cache_info(void)
81{
82}
83
84static inline struct folio *swap_cluster_readahead(swp_entry_t entry,
85			gfp_t gfp_mask, struct mempolicy *mpol, pgoff_t ilx)
86{
87	return NULL;
88}
89
90static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
91			struct vm_fault *vmf)
92{
93	return NULL;
94}
95
96static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
97{
98	return 0;
99}
100
101static inline void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry)
102{
103}
104
105static inline struct folio *swap_cache_get_folio(swp_entry_t entry,
106		struct vm_area_struct *vma, unsigned long addr)
107{
108	return NULL;
109}
110
111static inline
112struct folio *filemap_get_incore_folio(struct address_space *mapping,
113		pgoff_t index)
114{
115	return filemap_get_folio(mapping, index);
116}
117
118static inline bool add_to_swap(struct folio *folio)
119{
120	return false;
121}
122
123static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
124{
125	return NULL;
126}
127
128static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
129					gfp_t gfp_mask, void **shadowp)
130{
131	return -1;
132}
133
134static inline void __delete_from_swap_cache(struct folio *folio,
135					swp_entry_t entry, void *shadow)
136{
137}
138
139static inline void delete_from_swap_cache(struct folio *folio)
140{
141}
142
143static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
144				unsigned long end)
145{
146}
147
148static inline unsigned int folio_swap_flags(struct folio *folio)
149{
150	return 0;
151}
152#endif /* CONFIG_SWAP */
153#endif /* _MM_SWAP_H */
154