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 */