| #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) |
| extern void FASTCALL(page_cache_release(struct page *)); |
| |
| 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); |
| } |
| |
| extern void wake_up_page(struct page *); |
| |
| extern struct page * grab_cache_page (struct address_space *, unsigned long); |
| 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 |