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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_alloc() alloc_pages(GFP_HIGHUSER, 0)
#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) 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.
*/
extern 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 void lock_page(struct page *page);
#define find_lock_page(mapping, index) \
__find_lock_page(mapping, index, page_hash(mapping, index))
extern void __add_page_to_hash_queue(struct page * page, struct page **p);
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 inline void add_page_to_hash_queue(struct page * page, struct inode * inode, unsigned long index)
{
__add_page_to_hash_queue(page, page_hash(inode->i_mapping,index));
}
extern inline void add_page_to_inode_queue(struct address_space *mapping, struct page * page)
{
struct list_head *head = &mapping->pages;
if (!mapping->nrpages++) {
if (!list_empty(head))
BUG();
} else {
if (list_empty(head))
BUG();
}
list_add(&page->list, head);
page->mapping = mapping;
}
extern inline void remove_page_from_inode_queue(struct page * page)
{
struct address_space * mapping = page->mapping;
mapping->nrpages--;
list_del(&page->list);
}
extern void ___wait_on_page(struct page *);
extern inline void wait_on_page(struct page * page)
{
if (PageLocked(page))
___wait_on_page(page);
}
extern struct page * grab_cache_page (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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