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#ifndef _LINUX_PAGEMAP_H
#define _LINUX_PAGEMAP_H
#include <asm/system.h>
/*
* Page-mapping primitive inline functions
*
* Copyright 1995 Linus Torvalds
*/
#include <linux/mm.h>
#include <linux/fs.h>
static inline unsigned long page_address(struct page * page)
{
return PAGE_OFFSET + ((page - mem_map) << PAGE_SHIFT);
}
/*
* 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_alloc() __get_free_page(GFP_USER)
#define page_cache_free(x) free_page(x)
#define page_cache_release(x) __free_page(x)
/*
* From a kernel address, get the "struct page *"
*/
#define page_cache_entry(x) (mem_map + MAP_NR(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 offsets are distributed (ie, we
* roughly know which bits are "significant")
*/
static inline unsigned long _page_hashfn(struct inode * inode, unsigned long offset)
{
#define i (((unsigned long) inode)/(sizeof(struct inode) & ~ (sizeof(struct inode) - 1)))
#define o (offset >> PAGE_SHIFT)
#define s(x) ((x)+((x)>>PAGE_HASH_BITS))
return s(i+o) & (PAGE_HASH_SIZE-1);
#undef i
#undef o
#undef s
}
#define page_hash(inode,offset) (page_hash_table+_page_hashfn(inode,offset))
extern struct page * __find_get_page (struct inode * inode,
unsigned long offset, struct page **hash);
#define find_get_page(inode, offset) \
__find_get_page(inode, offset, page_hash(inode, offset))
extern struct page * __find_lock_page (struct inode * inode,
unsigned long offset, struct page **hash);
extern void lock_page(struct page *page);
#define find_lock_page(inode, offset) \
__find_lock_page(inode, offset, page_hash(inode, offset))
extern void __add_page_to_hash_queue(struct page * page, struct page **p);
extern void add_to_page_cache(struct page * page, struct inode * inode, unsigned long offset);
extern int add_to_page_cache_unique(struct page * page, struct inode * inode, unsigned long offset, struct page **hash);
static inline void add_page_to_hash_queue(struct page * page, struct inode * inode, unsigned long offset)
{
__add_page_to_hash_queue(page, page_hash(inode,offset));
}
static inline void add_page_to_inode_queue(struct inode * inode, struct page * page)
{
struct page **p = &inode->i_pages;
inode->i_nrpages++;
page->inode = inode;
page->prev = NULL;
if ((page->next = *p) != NULL)
page->next->prev = page;
*p = page;
}
extern void ___wait_on_page(struct page *);
static inline void wait_on_page(struct page * page)
{
if (PageLocked(page))
___wait_on_page(page);
}
extern void update_vm_cache(struct inode *, unsigned long, const char *, int);
#endif
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