[mirror_ubuntu-jammy-kernel.git] / include / linux / swap.h

#ifndef _LINUX_SWAP_H
#define _LINUX_SWAP_H

#include <linux/spinlock.h>
#include <linux/linkage.h>
#include <linux/mmzone.h>
#include <linux/list.h>
#include <linux/memcontrol.h>
#include <linux/sched.h>

#include <asm/atomic.h>
#include <asm/page.h>

struct notifier_block;

struct bio;

#define SWAP_FLAG_PREFER	0x8000	/* set if swap priority specified */
#define SWAP_FLAG_PRIO_MASK	0x7fff
#define SWAP_FLAG_PRIO_SHIFT	0

static inline int current_is_kswapd(void)
{
	return current->flags & PF_KSWAPD;
}

/*
 * MAX_SWAPFILES defines the maximum number of swaptypes: things which can
 * be swapped to.  The swap type and the offset into that swap type are
 * encoded into pte's and into pgoff_t's in the swapcache.  Using five bits
 * for the type means that the maximum number of swapcache pages is 27 bits
 * on 32-bit-pgoff_t architectures.  And that assumes that the architecture packs
 * the type/offset into the pte as 5/27 as well.
 */
#define MAX_SWAPFILES_SHIFT	5
#ifndef CONFIG_MIGRATION
#define MAX_SWAPFILES		(1 << MAX_SWAPFILES_SHIFT)
#else
/* Use last two entries for page migration swap entries */
#define MAX_SWAPFILES		((1 << MAX_SWAPFILES_SHIFT)-2)
#define SWP_MIGRATION_READ	MAX_SWAPFILES
#define SWP_MIGRATION_WRITE	(MAX_SWAPFILES + 1)
#endif

/*
 * Magic header for a swap area. The first part of the union is
 * what the swap magic looks like for the old (limited to 128MB)
 * swap area format, the second part of the union adds - in the
 * old reserved area - some extra information. Note that the first
 * kilobyte is reserved for boot loader or disk label stuff...
 *
 * Having the magic at the end of the PAGE_SIZE makes detecting swap
 * areas somewhat tricky on machines that support multiple page sizes.
 * For 2.5 we'll probably want to move the magic to just beyond the
 * bootbits...
 */
union swap_header {
	struct {
		char reserved[PAGE_SIZE - 10];
		char magic[10];			/* SWAP-SPACE or SWAPSPACE2 */
	} magic;
	struct {
		char		bootbits[1024];	/* Space for disklabel etc. */
		__u32		version;
		__u32		last_page;
		__u32		nr_badpages;
		unsigned char	sws_uuid[16];
		unsigned char	sws_volume[16];
		__u32		padding[117];
		__u32		badpages[1];
	} info;
};

 /* A swap entry has to fit into a "unsigned long", as
  * the entry is hidden in the "index" field of the
  * swapper address space.
  */
typedef struct {
	unsigned long val;
} swp_entry_t;

/*
 * current->reclaim_state points to one of these when a task is running
 * memory reclaim
 */
struct reclaim_state {
	unsigned long reclaimed_slab;
};

#ifdef __KERNEL__

struct address_space;
struct sysinfo;
struct writeback_control;
struct zone;

/*
 * A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
 * disk blocks.  A list of swap extents maps the entire swapfile.  (Where the
 * term `swapfile' refers to either a blockdevice or an IS_REG file.  Apart
 * from setup, they're handled identically.
 *
 * We always assume that blocks are of size PAGE_SIZE.
 */
struct swap_extent {
	struct list_head list;
	pgoff_t start_page;
	pgoff_t nr_pages;
	sector_t start_block;
};

/*
 * Max bad pages in the new format..
 */
#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
#define MAX_SWAP_BADPAGES \
	((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))

enum {
	SWP_USED	= (1 << 0),	/* is slot in swap_info[] used? */
	SWP_WRITEOK	= (1 << 1),	/* ok to write to this swap?	*/
	SWP_ACTIVE	= (SWP_USED | SWP_WRITEOK),
					/* add others here before... */
	SWP_SCANNING	= (1 << 8),	/* refcount in scan_swap_map */
};

#define SWAP_CLUSTER_MAX 32

#define SWAP_MAP_MAX	0x7fff
#define SWAP_MAP_BAD	0x8000

/*
 * The in-memory structure used to track swap areas.
 */
struct swap_info_struct {
	unsigned int flags;
	int prio;			/* swap priority */
	struct file *swap_file;
	struct block_device *bdev;
	struct list_head extent_list;
	struct swap_extent *curr_swap_extent;
	unsigned old_block_size;
	unsigned short * swap_map;
	unsigned int lowest_bit;
	unsigned int highest_bit;
	unsigned int cluster_next;
	unsigned int cluster_nr;
	unsigned int pages;
	unsigned int max;
	unsigned int inuse_pages;
	int next;			/* next entry on swap list */
};

struct swap_list_t {
	int head;	/* head of priority-ordered swapfile list */
	int next;	/* swapfile to be used next */
};

/* Swap 50% full? Release swapcache more aggressively.. */
#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)

/* linux/mm/page_alloc.c */
extern unsigned long totalram_pages;
extern unsigned long totalreserve_pages;
extern long nr_swap_pages;
extern unsigned int nr_free_buffer_pages(void);
extern unsigned int nr_free_pagecache_pages(void);

/* Definition of global_page_state not available yet */
#define nr_free_pages() global_page_state(NR_FREE_PAGES)


/* linux/mm/swap.c */
extern void __lru_cache_add(struct page *, enum lru_list lru);
extern void lru_cache_add_lru(struct page *, enum lru_list lru);
extern void activate_page(struct page *);
extern void mark_page_accessed(struct page *);
extern void lru_add_drain(void);
extern int lru_add_drain_all(void);
extern void rotate_reclaimable_page(struct page *page);
extern void swap_setup(void);

extern void add_page_to_unevictable_list(struct page *page);

/**
 * lru_cache_add: add a page to the page lists
 * @page: the page to add
 */
static inline void lru_cache_add_anon(struct page *page)
{
	__lru_cache_add(page, LRU_INACTIVE_ANON);
}

static inline void lru_cache_add_active_anon(struct page *page)
{
	__lru_cache_add(page, LRU_ACTIVE_ANON);
}

static inline void lru_cache_add_file(struct page *page)
{
	__lru_cache_add(page, LRU_INACTIVE_FILE);
}

static inline void lru_cache_add_active_file(struct page *page)
{
	__lru_cache_add(page, LRU_ACTIVE_FILE);
}

/* linux/mm/vmscan.c */
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
					gfp_t gfp_mask);
extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
							gfp_t gfp_mask);
extern int __isolate_lru_page(struct page *page, int mode, int file);
extern unsigned long shrink_all_memory(unsigned long nr_pages);
extern int vm_swappiness;
extern int remove_mapping(struct address_space *mapping, struct page *page);
extern long vm_total_pages;

#ifdef CONFIG_NUMA
extern int zone_reclaim_mode;
extern int sysctl_min_unmapped_ratio;
extern int sysctl_min_slab_ratio;
extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
#else
#define zone_reclaim_mode 0
static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
{
	return 0;
}
#endif

#ifdef CONFIG_UNEVICTABLE_LRU
extern int page_evictable(struct page *page, struct vm_area_struct *vma);
#else
static inline int page_evictable(struct page *page,
						struct vm_area_struct *vma)
{
	return 1;
}
#endif

extern int kswapd_run(int nid);

#ifdef CONFIG_MMU
/* linux/mm/shmem.c */
extern int shmem_unuse(swp_entry_t entry, struct page *page);
#endif /* CONFIG_MMU */

extern void swap_unplug_io_fn(struct backing_dev_info *, struct page *);

#ifdef CONFIG_SWAP
/* linux/mm/page_io.c */
extern int swap_readpage(struct file *, struct page *);
extern int swap_writepage(struct page *page, struct writeback_control *wbc);
extern void end_swap_bio_read(struct bio *bio, int err);

/* linux/mm/swap_state.c */
extern struct address_space swapper_space;
#define total_swapcache_pages  swapper_space.nrpages
extern void show_swap_cache_info(void);
extern int add_to_swap(struct page *, gfp_t);
extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
extern void __delete_from_swap_cache(struct page *);
extern void delete_from_swap_cache(struct page *);
extern void free_page_and_swap_cache(struct page *);
extern void free_pages_and_swap_cache(struct page **, int);
extern struct page *lookup_swap_cache(swp_entry_t);
extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
			struct vm_area_struct *vma, unsigned long addr);
extern struct page *swapin_readahead(swp_entry_t, gfp_t,
			struct vm_area_struct *vma, unsigned long addr);

/* linux/mm/swapfile.c */
extern long total_swap_pages;
extern void si_swapinfo(struct sysinfo *);
extern swp_entry_t get_swap_page(void);
extern swp_entry_t get_swap_page_of_type(int);
extern int swap_duplicate(swp_entry_t);
extern int valid_swaphandles(swp_entry_t, unsigned long *);
extern void swap_free(swp_entry_t);
extern void free_swap_and_cache(swp_entry_t);
extern int swap_type_of(dev_t, sector_t, struct block_device **);
extern unsigned int count_swap_pages(int, int);
extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
extern sector_t swapdev_block(int, pgoff_t);
extern struct swap_info_struct *get_swap_info_struct(unsigned);
extern int can_share_swap_page(struct page *);
extern int remove_exclusive_swap_page(struct page *);
extern int remove_exclusive_swap_page_ref(struct page *);
struct backing_dev_info;

/* linux/mm/thrash.c */
extern struct mm_struct * swap_token_mm;
extern void grab_swap_token(void);
extern void __put_swap_token(struct mm_struct *);

static inline int has_swap_token(struct mm_struct *mm)
{
	return (mm == swap_token_mm);
}

static inline void put_swap_token(struct mm_struct *mm)
{
	if (has_swap_token(mm))
		__put_swap_token(mm);
}

static inline void disable_swap_token(void)
{
	put_swap_token(swap_token_mm);
}

#else /* CONFIG_SWAP */

#define total_swap_pages			0
#define total_swapcache_pages			0UL

#define si_swapinfo(val) \
	do { (val)->freeswap = (val)->totalswap = 0; } while (0)
/* only sparc can not include linux/pagemap.h in this file
 * so leave page_cache_release and release_pages undeclared... */
#define free_page_and_swap_cache(page) \
	page_cache_release(page)
#define free_pages_and_swap_cache(pages, nr) \
	release_pages((pages), (nr), 0);

static inline void show_swap_cache_info(void)
{
}

static inline void free_swap_and_cache(swp_entry_t swp)
{
}

static inline int swap_duplicate(swp_entry_t swp)
{
	return 0;
}

static inline void swap_free(swp_entry_t swp)
{
}

static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
			struct vm_area_struct *vma, unsigned long addr)
{
	return NULL;
}

static inline struct page *lookup_swap_cache(swp_entry_t swp)
{
	return NULL;
}

#define can_share_swap_page(p)			(page_mapcount(p) == 1)

static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
							gfp_t gfp_mask)
{
	return -1;
}

static inline void __delete_from_swap_cache(struct page *page)
{
}

static inline void delete_from_swap_cache(struct page *page)
{
}

#define swap_token_default_timeout		0

static inline int remove_exclusive_swap_page(struct page *p)
{
	return 0;
}

static inline int remove_exclusive_swap_page_ref(struct page *page)
{
	return 0;
}

static inline swp_entry_t get_swap_page(void)
{
	swp_entry_t entry;
	entry.val = 0;
	return entry;
}

/* linux/mm/thrash.c */
#define put_swap_token(x) do { } while(0)
#define grab_swap_token()  do { } while(0)
#define has_swap_token(x) 0
#define disable_swap_token() do { } while(0)

#endif /* CONFIG_SWAP */
#endif /* __KERNEL__*/
#endif /* _LINUX_SWAP_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef _LINUX_SWAP_H
	2	#define _LINUX_SWAP_H
	3
1da177e4 LT	4	#include <linux/spinlock.h>
	5	#include <linux/linkage.h>
	6	#include <linux/mmzone.h>
	7	#include <linux/list.h>
66e1707b	8	#include <linux/memcontrol.h>
1da177e4	9	#include <linux/sched.h>
542d1c88	10
1da177e4 LT	11	#include <asm/atomic.h>
	12	#include <asm/page.h>
	13
8bc719d3 MS	14	struct notifier_block;
8bc719d3 MS	15
ab954160 AM	16	struct bio;
ab954160 AM	17
1da177e4 LT	18	#define SWAP_FLAG_PREFER 0x8000 /* set if swap priority specified */
	19	#define SWAP_FLAG_PRIO_MASK 0x7fff
	20	#define SWAP_FLAG_PRIO_SHIFT 0
	21
	22	static inline int current_is_kswapd(void)
	23	{
	24	return current->flags & PF_KSWAPD;
	25	}
	26
	27	/*
	28	* MAX_SWAPFILES defines the maximum number of swaptypes: things which can
	29	* be swapped to. The swap type and the offset into that swap type are
	30	* encoded into pte's and into pgoff_t's in the swapcache. Using five bits
	31	* for the type means that the maximum number of swapcache pages is 27 bits
	32	* on 32-bit-pgoff_t architectures. And that assumes that the architecture packs
	33	* the type/offset into the pte as 5/27 as well.
	34	*/
	35	#define MAX_SWAPFILES_SHIFT 5
0697212a	36	#ifndef CONFIG_MIGRATION
1da177e4	37	#define MAX_SWAPFILES (1 << MAX_SWAPFILES_SHIFT)
0697212a CL	38	#else
	39	/* Use last two entries for page migration swap entries */
	40	#define MAX_SWAPFILES ((1 << MAX_SWAPFILES_SHIFT)-2)
	41	#define SWP_MIGRATION_READ MAX_SWAPFILES
	42	#define SWP_MIGRATION_WRITE (MAX_SWAPFILES + 1)
	43	#endif
1da177e4 LT	44
	45	/*
	46	* Magic header for a swap area. The first part of the union is
	47	* what the swap magic looks like for the old (limited to 128MB)
	48	* swap area format, the second part of the union adds - in the
	49	* old reserved area - some extra information. Note that the first
	50	* kilobyte is reserved for boot loader or disk label stuff...
	51	*
	52	* Having the magic at the end of the PAGE_SIZE makes detecting swap
	53	* areas somewhat tricky on machines that support multiple page sizes.
	54	* For 2.5 we'll probably want to move the magic to just beyond the
	55	* bootbits...
	56	*/
	57	union swap_header {
	58	struct {
	59	char reserved[PAGE_SIZE - 10];
	60	char magic[10]; /* SWAP-SPACE or SWAPSPACE2 */
	61	} magic;
	62	struct {
e8f03d02 AD	63	char bootbits[1024]; /* Space for disklabel etc. */
	64	__u32 version;
	65	__u32 last_page;
	66	__u32 nr_badpages;
	67	unsigned char sws_uuid[16];
	68	unsigned char sws_volume[16];
	69	__u32 padding[117];
	70	__u32 badpages[1];
1da177e4 LT	71	} info;
	72	};
	73
	74	/* A swap entry has to fit into a "unsigned long", as
	75	* the entry is hidden in the "index" field of the
	76	* swapper address space.
	77	*/
	78	typedef struct {
	79	unsigned long val;
	80	} swp_entry_t;
	81
	82	/*
	83	* current->reclaim_state points to one of these when a task is running
	84	* memory reclaim
	85	*/
	86	struct reclaim_state {
	87	unsigned long reclaimed_slab;
	88	};
	89
	90	#ifdef __KERNEL__
	91
	92	struct address_space;
	93	struct sysinfo;
	94	struct writeback_control;
	95	struct zone;
	96
	97	/*
	98	* A swap extent maps a range of a swapfile's PAGE_SIZE pages onto a range of
	99	* disk blocks. A list of swap extents maps the entire swapfile. (Where the
	100	* term `swapfile' refers to either a blockdevice or an IS_REG file. Apart
	101	* from setup, they're handled identically.
	102	*
	103	* We always assume that blocks are of size PAGE_SIZE.
	104	*/
	105	struct swap_extent {
	106	struct list_head list;
	107	pgoff_t start_page;
	108	pgoff_t nr_pages;
	109	sector_t start_block;
	110	};
	111
	112	/*
	113	* Max bad pages in the new format..
	114	*/
	115	#define __swapoffset(x) ((unsigned long)&((union swap_header *)0)->x)
	116	#define MAX_SWAP_BADPAGES \
	117	((__swapoffset(magic.magic) - __swapoffset(info.badpages)) / sizeof(int))
	118
	119	enum {
	120	SWP_USED = (1 << 0), /* is slot in swap_info[] used? */
	121	SWP_WRITEOK = (1 << 1), /* ok to write to this swap? */
	122	SWP_ACTIVE = (SWP_USED \| SWP_WRITEOK),
52b7efdb HD	123	/* add others here before... */
52b7efdb HD	124	SWP_SCANNING = (1 << 8), /* refcount in scan_swap_map */
1da177e4 LT	125	};
	126
	127	#define SWAP_CLUSTER_MAX 32
	128
	129	#define SWAP_MAP_MAX 0x7fff
	130	#define SWAP_MAP_BAD 0x8000
	131
	132	/*
	133	* The in-memory structure used to track swap areas.
1da177e4 LT	134	*/
	135	struct swap_info_struct {
	136	unsigned int flags;
5d337b91	137	int prio; /* swap priority */
1da177e4 LT	138	struct file *swap_file;
	139	struct block_device *bdev;
	140	struct list_head extent_list;
1da177e4 LT	141	struct swap_extent *curr_swap_extent;
	142	unsigned old_block_size;
	143	unsigned short * swap_map;
	144	unsigned int lowest_bit;
	145	unsigned int highest_bit;
	146	unsigned int cluster_next;
	147	unsigned int cluster_nr;
6eb396dc HD	148	unsigned int pages;
	149	unsigned int max;
	150	unsigned int inuse_pages;
1da177e4 LT	151	int next; /* next entry on swap list */
	152	};
	153
	154	struct swap_list_t {
	155	int head; /* head of priority-ordered swapfile list */
	156	int next; /* swapfile to be used next */
	157	};
	158
	159	/* Swap 50% full? Release swapcache more aggressively.. */
	160	#define vm_swap_full() (nr_swap_pages*2 < total_swap_pages)
	161
1da177e4 LT	162	/* linux/mm/page_alloc.c */
1da177e4 LT	163	extern unsigned long totalram_pages;
cb45b0e9	164	extern unsigned long totalreserve_pages;
1da177e4	165	extern long nr_swap_pages;
1da177e4 LT	166	extern unsigned int nr_free_buffer_pages(void);
	167	extern unsigned int nr_free_pagecache_pages(void);
	168
96177299 CL	169	/* Definition of global_page_state not available yet */
	170	#define nr_free_pages() global_page_state(NR_FREE_PAGES)
	171
	172
1da177e4	173	/* linux/mm/swap.c */
f04e9ebb KM	174	extern void __lru_cache_add(struct page *, enum lru_list lru);
f04e9ebb KM	175	extern void lru_cache_add_lru(struct page *, enum lru_list lru);
b3c97528 HH	176	extern void activate_page(struct page *);
b3c97528 HH	177	extern void mark_page_accessed(struct page *);
1da177e4	178	extern void lru_add_drain(void);
053837fc	179	extern int lru_add_drain_all(void);
ac6aadb2	180	extern void rotate_reclaimable_page(struct page *page);
1da177e4 LT	181	extern void swap_setup(void);
1da177e4 LT	182
894bc310 LS	183	extern void add_page_to_unevictable_list(struct page *page);
894bc310 LS	184
f04e9ebb KM	185	/**
	186	* lru_cache_add: add a page to the page lists
	187	* @page: the page to add
	188	*/
4f98a2fe	189	static inline void lru_cache_add_anon(struct page *page)
f04e9ebb	190	{
4f98a2fe	191	__lru_cache_add(page, LRU_INACTIVE_ANON);
f04e9ebb KM	192	}
f04e9ebb KM	193
4f98a2fe	194	static inline void lru_cache_add_active_anon(struct page *page)
f04e9ebb	195	{
4f98a2fe RR	196	__lru_cache_add(page, LRU_ACTIVE_ANON);
	197	}
	198
	199	static inline void lru_cache_add_file(struct page *page)
	200	{
	201	__lru_cache_add(page, LRU_INACTIVE_FILE);
	202	}
	203
	204	static inline void lru_cache_add_active_file(struct page *page)
	205	{
	206	__lru_cache_add(page, LRU_ACTIVE_FILE);
f04e9ebb KM	207	}
f04e9ebb KM	208
1da177e4	209	/* linux/mm/vmscan.c */
dac1d27b	210	extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
5ad333eb	211	gfp_t gfp_mask);
e1a1cd59 BS	212	extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *mem,
e1a1cd59 BS	213	gfp_t gfp_mask);
4f98a2fe	214	extern int __isolate_lru_page(struct page *page, int mode, int file);
69e05944	215	extern unsigned long shrink_all_memory(unsigned long nr_pages);
1da177e4	216	extern int vm_swappiness;
b20a3503	217	extern int remove_mapping(struct address_space mapping, struct page page);
bd1e22b8	218	extern long vm_total_pages;
b20a3503	219
9eeff239 CL	220	#ifdef CONFIG_NUMA
9eeff239 CL	221	extern int zone_reclaim_mode;
9614634f	222	extern int sysctl_min_unmapped_ratio;
0ff38490	223	extern int sysctl_min_slab_ratio;
9eeff239 CL	224	extern int zone_reclaim(struct zone *, gfp_t, unsigned int);
	225	#else
	226	#define zone_reclaim_mode 0
	227	static inline int zone_reclaim(struct zone *z, gfp_t mask, unsigned int order)
	228	{
	229	return 0;
	230	}
	231	#endif
	232
894bc310 LS	233	#ifdef CONFIG_UNEVICTABLE_LRU
	234	extern int page_evictable(struct page page, struct vm_area_struct vma);
	235	#else
	236	static inline int page_evictable(struct page *page,
	237	struct vm_area_struct *vma)
	238	{
	239	return 1;
	240	}
	241	#endif
	242
3218ae14 YG	243	extern int kswapd_run(int nid);
3218ae14 YG	244
1da177e4 LT	245	#ifdef CONFIG_MMU
	246	/* linux/mm/shmem.c */
	247	extern int shmem_unuse(swp_entry_t entry, struct page *page);
	248	#endif /* CONFIG_MMU */
	249
	250	extern void swap_unplug_io_fn(struct backing_dev_info , struct page );
	251
	252	#ifdef CONFIG_SWAP
	253	/* linux/mm/page_io.c */
	254	extern int swap_readpage(struct file , struct page );
	255	extern int swap_writepage(struct page page, struct writeback_control wbc);
6712ecf8	256	extern void end_swap_bio_read(struct bio *bio, int err);
1da177e4 LT	257
	258	/* linux/mm/swap_state.c */
	259	extern struct address_space swapper_space;
	260	#define total_swapcache_pages swapper_space.nrpages
	261	extern void show_swap_cache_info(void);
1480a540	262	extern int add_to_swap(struct page *, gfp_t);
73b1262f	263	extern int add_to_swap_cache(struct page *, swp_entry_t, gfp_t);
1da177e4 LT	264	extern void __delete_from_swap_cache(struct page *);
1da177e4 LT	265	extern void delete_from_swap_cache(struct page *);
1da177e4 LT	266	extern void free_page_and_swap_cache(struct page *);
1da177e4 LT	267	extern void free_pages_and_swap_cache(struct page **, int);
46017e95	268	extern struct page *lookup_swap_cache(swp_entry_t);
02098fea	269	extern struct page *read_swap_cache_async(swp_entry_t, gfp_t,
46017e95	270	struct vm_area_struct *vma, unsigned long addr);
02098fea	271	extern struct page *swapin_readahead(swp_entry_t, gfp_t,
46017e95 HD	272	struct vm_area_struct *vma, unsigned long addr);
46017e95 HD	273
1da177e4 LT	274	/* linux/mm/swapfile.c */
1da177e4 LT	275	extern long total_swap_pages;
1da177e4 LT	276	extern void si_swapinfo(struct sysinfo *);
1da177e4 LT	277	extern swp_entry_t get_swap_page(void);
f577eb30	278	extern swp_entry_t get_swap_page_of_type(int);
1da177e4 LT	279	extern int swap_duplicate(swp_entry_t);
	280	extern int valid_swaphandles(swp_entry_t, unsigned long *);
	281	extern void swap_free(swp_entry_t);
	282	extern void free_swap_and_cache(swp_entry_t);
7bf23687	283	extern int swap_type_of(dev_t, sector_t, struct block_device **);
f577eb30	284	extern unsigned int count_swap_pages(int, int);
1da177e4	285	extern sector_t map_swap_page(struct swap_info_struct *, pgoff_t);
3aef83e0	286	extern sector_t swapdev_block(int, pgoff_t);
1da177e4 LT	287	extern struct swap_info_struct *get_swap_info_struct(unsigned);
	288	extern int can_share_swap_page(struct page *);
	289	extern int remove_exclusive_swap_page(struct page *);
68a22394	290	extern int remove_exclusive_swap_page_ref(struct page *);
1da177e4 LT	291	struct backing_dev_info;
1da177e4 LT	292
1da177e4 LT	293	/* linux/mm/thrash.c */
1da177e4 LT	294	extern struct mm_struct * swap_token_mm;
1da177e4 LT	295	extern void grab_swap_token(void);
	296	extern void __put_swap_token(struct mm_struct *);
	297
	298	static inline int has_swap_token(struct mm_struct *mm)
	299	{
	300	return (mm == swap_token_mm);
	301	}
	302
	303	static inline void put_swap_token(struct mm_struct *mm)
	304	{
	305	if (has_swap_token(mm))
	306	__put_swap_token(mm);
	307	}
	308
f7b7fd8f RR	309	static inline void disable_swap_token(void)
	310	{
	311	put_swap_token(swap_token_mm);
	312	}
	313
1da177e4 LT	314	#else /* CONFIG_SWAP */
	315
	316	#define total_swap_pages 0
	317	#define total_swapcache_pages 0UL
	318
	319	#define si_swapinfo(val) \
	320	do { (val)->freeswap = (val)->totalswap = 0; } while (0)
9ae5b3c7 OH	321	/* only sparc can not include linux/pagemap.h in this file
9ae5b3c7 OH	322	* so leave page_cache_release and release_pages undeclared... */
1da177e4 LT	323	#define free_page_and_swap_cache(page) \
	324	page_cache_release(page)
	325	#define free_pages_and_swap_cache(pages, nr) \
	326	release_pages((pages), (nr), 0);
	327
bd96b9eb CK	328	static inline void show_swap_cache_info(void)
	329	{
	330	}
	331
	332	static inline void free_swap_and_cache(swp_entry_t swp)
	333	{
	334	}
	335
	336	static inline int swap_duplicate(swp_entry_t swp)
	337	{
	338	return 0;
	339	}
	340
	341	static inline void swap_free(swp_entry_t swp)
	342	{
	343	}
	344
02098fea	345	static inline struct page *swapin_readahead(swp_entry_t swp, gfp_t gfp_mask,
bd96b9eb CK	346	struct vm_area_struct *vma, unsigned long addr)
	347	{
	348	return NULL;
	349	}
	350
	351	static inline struct page *lookup_swap_cache(swp_entry_t swp)
	352	{
	353	return NULL;
	354	}
	355
e6333fd4	356	#define can_share_swap_page(p) (page_mapcount(p) == 1)
bd96b9eb	357
73b1262f HD	358	static inline int add_to_swap_cache(struct page *page, swp_entry_t entry,
73b1262f HD	359	gfp_t gfp_mask)
bd96b9eb	360	{
73b1262f	361	return -1;
bd96b9eb CK	362	}
	363
	364	static inline void __delete_from_swap_cache(struct page *page)
	365	{
	366	}
	367
	368	static inline void delete_from_swap_cache(struct page *page)
	369	{
	370	}
	371
1da177e4 LT	372	#define swap_token_default_timeout 0
	373
	374	static inline int remove_exclusive_swap_page(struct page *p)
	375	{
	376	return 0;
	377	}
	378
68a22394 RR	379	static inline int remove_exclusive_swap_page_ref(struct page *page)
	380	{
	381	return 0;
	382	}
	383
1da177e4 LT	384	static inline swp_entry_t get_swap_page(void)
	385	{
	386	swp_entry_t entry;
	387	entry.val = 0;
	388	return entry;
	389	}
	390
	391	/* linux/mm/thrash.c */
	392	#define put_swap_token(x) do { } while(0)
	393	#define grab_swap_token() do { } while(0)
	394	#define has_swap_token(x) 0
f7b7fd8f	395	#define disable_swap_token() do { } while(0)
1da177e4 LT	396
	397	#endif /* CONFIG_SWAP */
	398	#endif /* __KERNEL__*/
	399	#endif /* _LINUX_SWAP_H */