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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _MM_SWAP_H
#define _MM_SWAP_H
struct mempolicy;
#ifdef CONFIG_SWAP
#include <linux/swapops.h> /* for swp_offset */
#include <linux/blk_types.h> /* for bio_end_io_t */
/* linux/mm/page_io.c */
int sio_pool_init(void);
struct swap_iocb;
void swap_read_folio(struct folio *folio, struct swap_iocb **plug);
void __swap_read_unplug(struct swap_iocb *plug);
static inline void swap_read_unplug(struct swap_iocb *plug)
{
if (unlikely(plug))
__swap_read_unplug(plug);
}
void swap_write_unplug(struct swap_iocb *sio);
int swap_writepage(struct page *page, struct writeback_control *wbc);
void __swap_writepage(struct folio *folio, struct writeback_control *wbc);
/* linux/mm/swap_state.c */
/* One swap address space for each 64M swap space */
#define SWAP_ADDRESS_SPACE_SHIFT 14
#define SWAP_ADDRESS_SPACE_PAGES (1 << SWAP_ADDRESS_SPACE_SHIFT)
#define SWAP_ADDRESS_SPACE_MASK (SWAP_ADDRESS_SPACE_PAGES - 1)
extern struct address_space *swapper_spaces[];
#define swap_address_space(entry) \
(&swapper_spaces[swp_type(entry)][swp_offset(entry) \
>> SWAP_ADDRESS_SPACE_SHIFT])
/*
* Return the swap device position of the swap entry.
*/
static inline loff_t swap_dev_pos(swp_entry_t entry)
{
return ((loff_t)swp_offset(entry)) << PAGE_SHIFT;
}
/*
* Return the swap cache index of the swap entry.
*/
static inline pgoff_t swap_cache_index(swp_entry_t entry)
{
BUILD_BUG_ON((SWP_OFFSET_MASK | SWAP_ADDRESS_SPACE_MASK) != SWP_OFFSET_MASK);
return swp_offset(entry) & SWAP_ADDRESS_SPACE_MASK;
}
void show_swap_cache_info(void);
bool add_to_swap(struct folio *folio);
void *get_shadow_from_swap_cache(swp_entry_t entry);
int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
gfp_t gfp, void **shadowp);
void __delete_from_swap_cache(struct folio *folio,
swp_entry_t entry, void *shadow);
void delete_from_swap_cache(struct folio *folio);
void clear_shadow_from_swap_cache(int type, unsigned long begin,
unsigned long end);
void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr);
struct folio *swap_cache_get_folio(swp_entry_t entry,
struct vm_area_struct *vma, unsigned long addr);
struct folio *filemap_get_incore_folio(struct address_space *mapping,
pgoff_t index);
struct folio *read_swap_cache_async(swp_entry_t entry, gfp_t gfp_mask,
struct vm_area_struct *vma, unsigned long addr,
struct swap_iocb **plug);
struct folio *__read_swap_cache_async(swp_entry_t entry, gfp_t gfp_flags,
struct mempolicy *mpol, pgoff_t ilx, bool *new_page_allocated,
bool skip_if_exists);
struct folio *swap_cluster_readahead(swp_entry_t entry, gfp_t flag,
struct mempolicy *mpol, pgoff_t ilx);
struct folio *swapin_readahead(swp_entry_t entry, gfp_t flag,
struct vm_fault *vmf);
static inline unsigned int folio_swap_flags(struct folio *folio)
{
return swp_swap_info(folio->swap)->flags;
}
/*
* Return the count of contiguous swap entries that share the same
* zeromap status as the starting entry. If is_zeromap is not NULL,
* it will return the zeromap status of the starting entry.
*/
static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr,
bool *is_zeromap)
{
struct swap_info_struct *sis = swp_swap_info(entry);
unsigned long start = swp_offset(entry);
unsigned long end = start + max_nr;
bool first_bit;
first_bit = test_bit(start, sis->zeromap);
if (is_zeromap)
*is_zeromap = first_bit;
if (max_nr <= 1)
return max_nr;
if (first_bit)
return find_next_zero_bit(sis->zeromap, end, start) - start;
else
return find_next_bit(sis->zeromap, end, start) - start;
}
#else /* CONFIG_SWAP */
struct swap_iocb;
static inline void swap_read_folio(struct folio *folio, struct swap_iocb **plug)
{
}
static inline void swap_write_unplug(struct swap_iocb *sio)
{
}
static inline struct address_space *swap_address_space(swp_entry_t entry)
{
return NULL;
}
static inline pgoff_t swap_cache_index(swp_entry_t entry)
{
return 0;
}
static inline void show_swap_cache_info(void)
{
}
static inline struct folio *swap_cluster_readahead(swp_entry_t entry,
gfp_t gfp_mask, struct mempolicy *mpol, pgoff_t ilx)
{
return NULL;
}
static inline struct folio *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
struct vm_fault *vmf)
{
return NULL;
}
static inline int swap_writepage(struct page *p, struct writeback_control *wbc)
{
return 0;
}
static inline void swapcache_clear(struct swap_info_struct *si, swp_entry_t entry, int nr)
{
}
static inline struct folio *swap_cache_get_folio(swp_entry_t entry,
struct vm_area_struct *vma, unsigned long addr)
{
return NULL;
}
static inline
struct folio *filemap_get_incore_folio(struct address_space *mapping,
pgoff_t index)
{
return filemap_get_folio(mapping, index);
}
static inline bool add_to_swap(struct folio *folio)
{
return false;
}
static inline void *get_shadow_from_swap_cache(swp_entry_t entry)
{
return NULL;
}
static inline int add_to_swap_cache(struct folio *folio, swp_entry_t entry,
gfp_t gfp_mask, void **shadowp)
{
return -1;
}
static inline void __delete_from_swap_cache(struct folio *folio,
swp_entry_t entry, void *shadow)
{
}
static inline void delete_from_swap_cache(struct folio *folio)
{
}
static inline void clear_shadow_from_swap_cache(int type, unsigned long begin,
unsigned long end)
{
}
static inline unsigned int folio_swap_flags(struct folio *folio)
{
return 0;
}
static inline int swap_zeromap_batch(swp_entry_t entry, int max_nr,
bool *has_zeromap)
{
return 0;
}
#endif /* CONFIG_SWAP */
#endif /* _MM_SWAP_H */
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