1 #ifndef _LINUX_PAGEMAP_H
2 #define _LINUX_PAGEMAP_H
3
4 /*
5 * Page-mapping primitive inline functions
6 *
7 * Copyright 1995 Linus Torvalds
8 */
9
10 #include <linux/mm.h>
11 #include <linux/fs.h>
12 #include <linux/list.h>
13
14 #include <asm/system.h>
15 #include <asm/pgtable.h>
16 #include <linux/highmem.h>
17
18 /*
19 * The page cache can done in larger chunks than
20 * one page, because it allows for more efficient
21 * throughput (it can then be mapped into user
22 * space in smaller chunks for same flexibility).
23 *
24 * Or rather, it _will_ be done in larger chunks.
25 */
26 #define PAGE_CACHE_SHIFT PAGE_SHIFT
27 #define PAGE_CACHE_SIZE PAGE_SIZE
28 #define PAGE_CACHE_MASK PAGE_MASK
29 #define PAGE_CACHE_ALIGN(addr) (((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK)
30
31 #define page_cache_get(x) get_page(x)
32 #define page_cache_alloc() alloc_pages(GFP_HIGHUSER, 0)
33 #define page_cache_free(x) __free_page(x)
34 #define page_cache_release(x) __free_page(x)
35
36 /*
37 * From a kernel address, get the "struct page *"
38 */
39 #define page_cache_entry(x) virt_to_page(x)
40
41 extern unsigned int page_hash_bits;
42 #define PAGE_HASH_BITS (page_hash_bits)
43 #define PAGE_HASH_SIZE (1 << PAGE_HASH_BITS)
44
45 extern atomic_t page_cache_size; /* # of pages currently in the hash table */
46 extern struct page **page_hash_table;
47
48 extern void page_cache_init(unsigned long);
49
50 /*
51 * We use a power-of-two hash table to avoid a modulus,
52 * and get a reasonable hash by knowing roughly how the
53 * inode pointer and indexes are distributed (ie, we
54 * roughly know which bits are "significant")
55 *
56 * For the time being it will work for struct address_space too (most of
57 * them sitting inside the inodes). We might want to change it later.
58 */
59 extern inline unsigned long _page_hashfn(struct address_space * mapping, unsigned long index)
60 {
61 #define i (((unsigned long) mapping)/(sizeof(struct inode) & ~ (sizeof(struct inode) - 1)))
62 #define s(x) ((x)+((x)>>PAGE_HASH_BITS))
63 return s(i+index) & (PAGE_HASH_SIZE-1);
64 #undef i
65 #undef s
66 }
67
68 #define page_hash(mapping,index) (page_hash_table+_page_hashfn(mapping,index))
69
70 extern struct page * __find_get_page(struct address_space *mapping,
71 unsigned long offset, struct page **hash);
72 extern struct page * __find_lock_page (struct address_space * mapping,
73 unsigned long index, struct page **hash);
74 extern void lock_page(struct page *page);
75 #define find_lock_page(mapping, index) \
76 __find_lock_page(mapping, index, page_hash(mapping, index))
77
78 extern void __add_page_to_hash_queue(struct page * page, struct page **p);
79
80 extern void add_to_page_cache(struct page * page, struct address_space *mapping, unsigned long index);
81 extern void add_to_page_cache_locked(struct page * page, struct address_space *mapping, unsigned long index);
82
83 extern void ___wait_on_page(struct page *);
84
85 extern inline void wait_on_page(struct page * page)
86 {
87 if (PageLocked(page))
88 ___wait_on_page(page);
89 }
90
91 extern struct page * grab_cache_page (struct address_space *, unsigned long);
92
93 typedef int filler_t(void *, struct page*);
94
95 extern struct page *read_cache_page(struct address_space *, unsigned long,
96 filler_t *, void *);
97 #endif
98
This page was automatically generated by the
LXR engine.
Visit the LXR main site for more
information.