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#ifndef _LINUX_PAGEMAP_H
#define _LINUX_PAGEMAP_H
/*
* Page-mapping primitive inline functions
*
* Copyright 1995 Linus Torvalds
*/
#include <linux/mm.h>
#include <linux/fs.h>
#include <linux/list.h>
#include <asm/system.h>
#include <asm/pgtable.h>
#include <linux/highmem.h>
/*
* The page cache can done in larger chunks than
* one page, because it allows for more efficient
* throughput (it can then be mapped into user
* space in smaller chunks for same flexibility).
*
* Or rather, it _will_ be done in larger chunks.
*/
#define PAGE_CACHE_SHIFT PAGE_SHIFT
#define PAGE_CACHE_SIZE PAGE_SIZE
#define PAGE_CACHE_MASK PAGE_MASK
#define PAGE_CACHE_ALIGN(addr) (((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK)
#define page_cache_get(x) get_page(x)
#define page_cache_release(x) __free_page(x)
static inline struct page *page_cache_alloc(struct address_space *x)
{
return alloc_pages(x->gfp_mask, 0);
}
/*
* From a kernel address, get the "struct page *"
*/
#define page_cache_entry(x) virt_to_page(x)
extern unsigned int page_hash_bits;
#define PAGE_HASH_BITS (page_hash_bits)
#define PAGE_HASH_SIZE (1 << PAGE_HASH_BITS)
extern atomic_t page_cache_size; /* # of pages currently in the hash table */
extern struct page **page_hash_table;
extern void page_cache_init(unsigned long);
/*
* We use a power-of-two hash table to avoid a modulus,
* and get a reasonable hash by knowing roughly how the
* inode pointer and indexes are distributed (ie, we
* roughly know which bits are "significant")
*
* For the time being it will work for struct address_space too (most of
* them sitting inside the inodes). We might want to change it later.
*/
static inline unsigned long _page_hashfn(struct address_space * mapping, unsigned long index)
{
#define i (((unsigned long) mapping)/(sizeof(struct inode) & ~ (sizeof(struct inode) - 1)))
#define s(x) ((x)+((x)>>PAGE_HASH_BITS))
return s(i+index) & (PAGE_HASH_SIZE-1);
#undef i
#undef s
}
#define page_hash(mapping,index) (page_hash_table+_page_hashfn(mapping,index))
extern struct page * __find_get_page(struct address_space *mapping,
unsigned long index, struct page **hash);
#define find_get_page(mapping, index) \
__find_get_page(mapping, index, page_hash(mapping, index))
extern struct page * __find_lock_page (struct address_space * mapping,
unsigned long index, struct page **hash);
extern struct page * find_or_create_page(struct address_space *mapping,
unsigned long index, unsigned int gfp_mask);
extern void FASTCALL(lock_page(struct page *page));
extern void FASTCALL(unlock_page(struct page *page));
#define find_lock_page(mapping, index) \
__find_lock_page(mapping, index, page_hash(mapping, index))
extern struct page *find_trylock_page(struct address_space *, unsigned long);
extern void add_to_page_cache(struct page * page, struct address_space *mapping, unsigned long index);
extern void add_to_page_cache_locked(struct page * page, struct address_space *mapping, unsigned long index);
extern int add_to_page_cache_unique(struct page * page, struct address_space *mapping, unsigned long index, struct page **hash);
extern void ___wait_on_page(struct page *);
static inline void wait_on_page(struct page * page)
{
if (PageLocked(page))
___wait_on_page(page);
}
/*
* Returns locked page at given index in given cache, creating it if needed.
*/
static inline struct page *grab_cache_page(struct address_space *mapping, unsigned long index)
{
return find_or_create_page(mapping, index, mapping->gfp_mask);
}
extern struct page * grab_cache_page_nowait (struct address_space *, unsigned long);
typedef int filler_t(void *, struct page*);
extern struct page *read_cache_page(struct address_space *, unsigned long,
filler_t *, void *);
#endif
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