1 #ifndef _LINUX_PAGEMAP_H
2 #define _LINUX_PAGEMAP_H
3
4 /*
5 * Copyright 1995 Linus Torvalds
6 */
7 #include <linux/mm.h>
8 #include <linux/fs.h>
9 #include <linux/list.h>
10 #include <linux/highmem.h>
11 #include <linux/compiler.h>
12 #include <asm/uaccess.h>
13 #include <linux/gfp.h>
14
15 /*
16 * Bits in mapping->flags. The lower __GFP_BITS_SHIFT bits are the page
17 * allocation mode flags.
18 */
19 #define AS_EIO (__GFP_BITS_SHIFT + 0) /* IO error on async write */
20 #define AS_ENOSPC (__GFP_BITS_SHIFT + 1) /* ENOSPC on async write */
21
mapping_gfp_mask(struct address_space * mapping)22 static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
23 {
24 return (__force gfp_t)mapping->flags & __GFP_BITS_MASK;
25 }
26
27 /*
28 * This is non-atomic. Only to be used before the mapping is activated.
29 * Probably needs a barrier...
30 */
mapping_set_gfp_mask(struct address_space * m,gfp_t mask)31 static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
32 {
33 m->flags = (m->flags & ~(__force unsigned long)__GFP_BITS_MASK) |
34 (__force unsigned long)mask;
35 }
36
37 /*
38 * The page cache can done in larger chunks than
39 * one page, because it allows for more efficient
40 * throughput (it can then be mapped into user
41 * space in smaller chunks for same flexibility).
42 *
43 * Or rather, it _will_ be done in larger chunks.
44 */
45 #define PAGE_CACHE_SHIFT PAGE_SHIFT
46 #define PAGE_CACHE_SIZE PAGE_SIZE
47 #define PAGE_CACHE_MASK PAGE_MASK
48 #define PAGE_CACHE_ALIGN(addr) (((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK)
49
50 #define page_cache_get(page) get_page(page)
51 #define page_cache_release(page) put_page(page)
52 void release_pages(struct page **pages, int nr, int cold);
53
54 #ifdef CONFIG_NUMA
55 extern struct page *page_cache_alloc(struct address_space *x);
56 extern struct page *page_cache_alloc_cold(struct address_space *x);
57 #else
page_cache_alloc(struct address_space * x)58 static inline struct page *page_cache_alloc(struct address_space *x)
59 {
60 return alloc_pages(mapping_gfp_mask(x), 0);
61 }
62
page_cache_alloc_cold(struct address_space * x)63 static inline struct page *page_cache_alloc_cold(struct address_space *x)
64 {
65 return alloc_pages(mapping_gfp_mask(x)|__GFP_COLD, 0);
66 }
67 #endif
68
69 typedef int filler_t(void *, struct page *);
70
71 extern struct page * find_get_page(struct address_space *mapping,
72 unsigned long index);
73 extern struct page * find_lock_page(struct address_space *mapping,
74 unsigned long index);
75 extern __deprecated_for_modules struct page * find_trylock_page(
76 struct address_space *mapping, unsigned long index);
77 extern struct page * find_or_create_page(struct address_space *mapping,
78 unsigned long index, gfp_t gfp_mask);
79 unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
80 unsigned int nr_pages, struct page **pages);
81 unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
82 unsigned int nr_pages, struct page **pages);
83 unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
84 int tag, unsigned int nr_pages, struct page **pages);
85
86 /*
87 * Returns locked page at given index in given cache, creating it if needed.
88 */
grab_cache_page(struct address_space * mapping,unsigned long index)89 static inline struct page *grab_cache_page(struct address_space *mapping, unsigned long index)
90 {
91 return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
92 }
93
94 extern struct page * grab_cache_page_nowait(struct address_space *mapping,
95 unsigned long index);
96 extern struct page * read_cache_page(struct address_space *mapping,
97 unsigned long index, filler_t *filler,
98 void *data);
99 extern int read_cache_pages(struct address_space *mapping,
100 struct list_head *pages, filler_t *filler, void *data);
101
read_mapping_page(struct address_space * mapping,unsigned long index,void * data)102 static inline struct page *read_mapping_page(struct address_space *mapping,
103 unsigned long index, void *data)
104 {
105 filler_t *filler = (filler_t *)mapping->a_ops->readpage;
106 return read_cache_page(mapping, index, filler, data);
107 }
108
109 int add_to_page_cache(struct page *page, struct address_space *mapping,
110 unsigned long index, gfp_t gfp_mask);
111 int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
112 unsigned long index, gfp_t gfp_mask);
113 extern void remove_from_page_cache(struct page *page);
114 extern void __remove_from_page_cache(struct page *page);
115
116 /*
117 * Return byte-offset into filesystem object for page.
118 */
page_offset(struct page * page)119 static inline loff_t page_offset(struct page *page)
120 {
121 return ((loff_t)page->index) << PAGE_CACHE_SHIFT;
122 }
123
linear_page_index(struct vm_area_struct * vma,unsigned long address)124 static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
125 unsigned long address)
126 {
127 pgoff_t pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
128 pgoff += vma->vm_pgoff;
129 return pgoff >> (PAGE_CACHE_SHIFT - PAGE_SHIFT);
130 }
131
132 extern void FASTCALL(__lock_page(struct page *page));
133 extern void FASTCALL(unlock_page(struct page *page));
134
lock_page(struct page * page)135 static inline void lock_page(struct page *page)
136 {
137 might_sleep();
138 if (TestSetPageLocked(page))
139 __lock_page(page);
140 }
141
142 /*
143 * This is exported only for wait_on_page_locked/wait_on_page_writeback.
144 * Never use this directly!
145 */
146 extern void FASTCALL(wait_on_page_bit(struct page *page, int bit_nr));
147
148 /*
149 * Wait for a page to be unlocked.
150 *
151 * This must be called with the caller "holding" the page,
152 * ie with increased "page->count" so that the page won't
153 * go away during the wait..
154 */
wait_on_page_locked(struct page * page)155 static inline void wait_on_page_locked(struct page *page)
156 {
157 if (PageLocked(page))
158 wait_on_page_bit(page, PG_locked);
159 }
160
161 /*
162 * Wait for a page to complete writeback
163 */
wait_on_page_writeback(struct page * page)164 static inline void wait_on_page_writeback(struct page *page)
165 {
166 if (PageWriteback(page))
167 wait_on_page_bit(page, PG_writeback);
168 }
169
170 extern void end_page_writeback(struct page *page);
171
172 /*
173 * Fault a userspace page into pagetables. Return non-zero on a fault.
174 *
175 * This assumes that two userspace pages are always sufficient. That's
176 * not true if PAGE_CACHE_SIZE > PAGE_SIZE.
177 */
fault_in_pages_writeable(char __user * uaddr,int size)178 static inline int fault_in_pages_writeable(char __user *uaddr, int size)
179 {
180 int ret;
181
182 /*
183 * Writing zeroes into userspace here is OK, because we know that if
184 * the zero gets there, we'll be overwriting it.
185 */
186 ret = __put_user(0, uaddr);
187 if (ret == 0) {
188 char __user *end = uaddr + size - 1;
189
190 /*
191 * If the page was already mapped, this will get a cache miss
192 * for sure, so try to avoid doing it.
193 */
194 if (((unsigned long)uaddr & PAGE_MASK) !=
195 ((unsigned long)end & PAGE_MASK))
196 ret = __put_user(0, end);
197 }
198 return ret;
199 }
200
fault_in_pages_readable(const char __user * uaddr,int size)201 static inline void fault_in_pages_readable(const char __user *uaddr, int size)
202 {
203 volatile char c;
204 int ret;
205
206 ret = __get_user(c, uaddr);
207 if (ret == 0) {
208 const char __user *end = uaddr + size - 1;
209
210 if (((unsigned long)uaddr & PAGE_MASK) !=
211 ((unsigned long)end & PAGE_MASK))
212 __get_user(c, end);
213 }
214 }
215
216 #endif /* _LINUX_PAGEMAP_H */
217