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 */
  9int sio_pool_init(void);
 10struct swap_iocb;
 11int swap_readpage(struct page *page, bool do_poll,
 12		  struct swap_iocb **plug);
 13void __swap_read_unplug(struct swap_iocb *plug);
 14static inline void swap_read_unplug(struct swap_iocb *plug)
 15{
 16	if (unlikely(plug))
 17		__swap_read_unplug(plug);
 18}
 19void swap_write_unplug(struct swap_iocb *sio);
 20int swap_writepage(struct page *page, struct writeback_control *wbc);
 21int __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)
 27extern 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
 32void show_swap_cache_info(void);
 33bool add_to_swap(struct folio *folio);
 34void *get_shadow_from_swap_cache(swp_entry_t entry);
 35int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
 36		      gfp_t gfp, void **shadowp);
 37void __delete_from_swap_cache(struct folio *folio,
 38			      swp_entry_t entry, void *shadow);
 39void delete_from_swap_cache(struct folio *folio);
 40void clear_shadow_from_swap_cache(int type, unsigned long begin,
 41				  unsigned long end);
 42struct folio *swap_cache_get_folio(swp_entry_t entry,
 43		struct vm_area_struct *vma, unsigned long addr);
 44struct folio *filemap_get_incore_folio(struct address_space *mapping,
 45		pgoff_t index);
 46
 47struct page *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
 48				   struct vm_area_struct *vma,
 49				   unsigned long addr,
 50				   bool do_poll,
 51				   struct swap_iocb **plug);
 52struct page *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
 53				     struct vm_area_struct *vma,
 54				     unsigned long addr,
 55				     bool *new_page_allocated);
 56struct page *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
 57				    struct vm_fault *vmf);
 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 page_swap_info(&folio->page)->flags;
 64}
 65#else /* CONFIG_SWAP */
 66struct swap_iocb;
 67static inline int swap_readpage(struct page *page, bool do_poll,
 68				struct swap_iocb **plug)
 69{
 70	return 0;
 71}
 72static inline void swap_write_unplug(struct swap_iocb *sio)
 73{
 74}
 75
 76static inline struct address_space *swap_address_space(swp_entry_t entry)
 77{
 78	return NULL;
 79}
 80
 81static inline void show_swap_cache_info(void)
 82{
 83}
 84
 85static inline struct page *swap_cluster_readahead(swp_entry_t entry,
 86				gfp_t gfp_mask, struct vm_fault *vmf)
 87{
 88	return NULL;
 89}
 90
 91static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
 92			struct vm_fault *vmf)
 93{
 94	return NULL;
 95}
 96
 97static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
 98{
 99	return 0;
100}
101
102static inline struct folio *swap_cache_get_folio(swp_entry_t entry,
103		struct vm_area_struct *vma, unsigned long addr)
104{
105	return NULL;
106}
107
108static inline
109struct folio *filemap_get_incore_folio(struct address_space *mapping,
110		pgoff_t index)
111{
112	return filemap_get_folio(mapping, index);
113}
114
115static inline bool add_to_swap(struct folio *folio)
116{
117	return false;
118}
119
120static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
121{
122	return NULL;
123}
124
125static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
126					gfp_t gfp_mask, void **shadowp)
127{
128	return -1;
129}
130
131static inline void __delete_from_swap_cache(struct folio *folio,
132					swp_entry_t entry, void *shadow)
133{
134}
135
136static inline void delete_from_swap_cache(struct folio *folio)
137{
138}
139
140static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
141				unsigned long end)
142{
143}
144
145static inline unsigned int folio_swap_flags(struct folio *folio)
146{
147	return 0;
148}
149#endif /* CONFIG_SWAP */
150#endif /* _MM_SWAP_H */