| 1 | #ifndef _LINUX_PAGEMAP_H
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| 2 | #define _LINUX_PAGEMAP_H
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| 3 |
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| 4 | /*
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| 5 | * Page-mapping primitive inline functions
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| 6 | *
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| 7 | * Copyright 1995 Linus Torvalds
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| 8 | */
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| 9 |
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| 10 | #include <linux/mm.h>
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| 11 | #include <linux/fs.h>
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| 12 | #include <linux/list.h>
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| 13 |
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| 14 | #include <asm/hardirq.h>
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| 15 | #include <asm/system.h>
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| 16 | #include <asm/pgtable.h>
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| 17 | #include <linux/bitops.h>
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| 18 |
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| 19 | /*
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| 20 | * The page cache can done in larger chunks than
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| 21 | * one page, because it allows for more efficient
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| 22 | * throughput (it can then be mapped into user
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| 23 | * space in smaller chunks for same flexibility).
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| 24 | *
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| 25 | * Or rather, it _will_ be done in larger chunks.
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| 26 | */
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| 27 | #define PAGE_CACHE_SHIFT PAGE_SHIFT
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| 28 | #define PAGE_CACHE_SIZE PAGE_SIZE
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| 29 | #define PAGE_CACHE_MASK PAGE_MASK
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| 30 | #define PAGE_CACHE_ALIGN(addr) (((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK)
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| 31 |
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| 32 | #define page_cache_alloc() alloc_pages(GFP_HIGHUSER, 0)
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| 33 | #define page_cache_free(x) __free_page(x)
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| 34 | #define page_cache_release(x) __free_page(x)
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| 35 |
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| 36 | /*
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| 37 | * From a kernel address, get the "struct page *"
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| 38 | */
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| 39 | #define page_cache_entry(x) (mem_map + MAP_NR(x))
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| 40 |
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| 41 | extern unsigned int page_hash_bits;
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| 42 | #define PAGE_HASH_BITS (page_hash_bits)
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| 43 | #define PAGE_HASH_SIZE (1 << PAGE_HASH_BITS)
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| 44 |
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| 45 | extern atomic_t page_cache_size; /* # of pages currently in the hash table */
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| 46 | extern struct page **page_hash_table;
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| 47 |
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| 48 | extern void page_cache_init(unsigned long);
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| 49 |
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| 50 | /*
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| 51 | * We use a power-of-two hash table to avoid a modulus,
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| 52 | * and get a reasonable hash by knowing roughly how the
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| 53 | * inode pointer and indexes are distributed (ie, we
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| 54 | * roughly know which bits are "significant")
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| 55 | *
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| 56 | * For the time being it will work for struct address_space too (most of
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| 57 | * them sitting inside the inodes). We might want to change it later.
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| 58 | */
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| 59 | //extern inline unsigned long _page_hashfn(struct address_space * mapping, unsigned long index)
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| 60 | //{
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| 61 | //#define i (((unsigned long) mapping)/(sizeof(struct inode) & ~ (sizeof(struct inode) - 1)))
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| 62 | //#define s(x) ((x)+((x)>>PAGE_HASH_BITS))
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| 63 | // return s(i+index) & (PAGE_HASH_SIZE-1);
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| 64 | //#undef i
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| 65 | //#undef o
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| 66 | //#undef s
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| 67 | //}
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| 68 |
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| 69 | #define page_hash(mapping,index) (page_hash_table+_page_hashfn(mapping,index))
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| 70 |
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| 71 | extern struct page * __find_get_page (struct address_space *mapping,
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| 72 | unsigned long index, struct page **hash);
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| 73 | #define find_get_page(mapping, index) \
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| 74 | __find_get_page(mapping, index, page_hash(mapping, index))
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| 75 | extern struct page * __find_lock_page (struct address_space * mapping,
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| 76 | unsigned long index, struct page **hash);
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| 77 | extern void lock_page(struct page *page);
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| 78 | #define find_lock_page(mapping, index) \
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| 79 | __find_lock_page(mapping, index, page_hash(mapping, index))
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| 80 |
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| 81 | extern void __add_page_to_hash_queue(struct page * page, struct page **p);
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| 82 |
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| 83 | extern void add_to_page_cache(struct page * page, struct address_space *mapping, unsigned long index);
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| 84 | extern int add_to_page_cache_unique(struct page * page, struct address_space *mapping, unsigned long index, struct page **hash);
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| 85 |
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| 86 | #if 0
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| 87 | extern inline void add_page_to_hash_queue(struct page * page, struct inode * inode, unsigned long index)
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| 88 | {
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| 89 | __add_page_to_hash_queue(page, page_hash(&inode->i_data,index));
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| 90 | }
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| 91 |
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| 92 | extern inline void add_page_to_inode_queue(struct address_space *mapping, struct page * page)
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| 93 | {
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| 94 | struct list_head *head = &mapping->pages;
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| 95 |
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| 96 | if (!mapping->nrpages++) {
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| 97 | if (!list_empty(head))
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| 98 | BUG();
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| 99 | } else {
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| 100 | if (list_empty(head))
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| 101 | BUG();
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| 102 | }
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| 103 | list_add(&page->list, head);
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| 104 | page->mapping = mapping;
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| 105 | }
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| 106 |
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| 107 | extern inline void remove_page_from_inode_queue(struct page * page)
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| 108 | {
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| 109 | struct address_space * mapping = page->mapping;
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| 110 |
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| 111 | mapping->nrpages--;
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| 112 | list_del(&page->list);
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| 113 | }
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| 114 |
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| 115 | extern void ___wait_on_page(struct page *);
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| 116 |
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| 117 | extern inline void wait_on_page(struct page * page)
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| 118 | {
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| 119 | if (PageLocked(page))
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| 120 | ___wait_on_page(page);
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| 121 | }
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| 122 | #endif
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| 123 |
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| 124 | #endif
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