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Linus Torvalds1da177e2005-04-16 15:20:36 -07001#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>
Guillaume Chazarain3e9f45b2007-05-08 00:23:25 -070014#include <linux/bitops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070015
16/*
17 * Bits in mapping->flags. The lower __GFP_BITS_SHIFT bits are the page
18 * allocation mode flags.
19 */
20#define AS_EIO (__GFP_BITS_SHIFT + 0) /* IO error on async write */
21#define AS_ENOSPC (__GFP_BITS_SHIFT + 1) /* ENOSPC on async write */
22
Guillaume Chazarain3e9f45b2007-05-08 00:23:25 -070023static inline void mapping_set_error(struct address_space *mapping, int error)
24{
25 if (error) {
26 if (error == -ENOSPC)
27 set_bit(AS_ENOSPC, &mapping->flags);
28 else
29 set_bit(AS_EIO, &mapping->flags);
30 }
31}
32
Al Virodd0fc662005-10-07 07:46:04 +010033static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
Linus Torvalds1da177e2005-04-16 15:20:36 -070034{
Al Viro260b2362005-10-21 03:22:44 -040035 return (__force gfp_t)mapping->flags & __GFP_BITS_MASK;
Linus Torvalds1da177e2005-04-16 15:20:36 -070036}
37
38/*
39 * This is non-atomic. Only to be used before the mapping is activated.
40 * Probably needs a barrier...
41 */
Al Viro260b2362005-10-21 03:22:44 -040042static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -070043{
Al Viro260b2362005-10-21 03:22:44 -040044 m->flags = (m->flags & ~(__force unsigned long)__GFP_BITS_MASK) |
45 (__force unsigned long)mask;
Linus Torvalds1da177e2005-04-16 15:20:36 -070046}
47
48/*
49 * The page cache can done in larger chunks than
50 * one page, because it allows for more efficient
51 * throughput (it can then be mapped into user
52 * space in smaller chunks for same flexibility).
53 *
54 * Or rather, it _will_ be done in larger chunks.
55 */
56#define PAGE_CACHE_SHIFT PAGE_SHIFT
57#define PAGE_CACHE_SIZE PAGE_SIZE
58#define PAGE_CACHE_MASK PAGE_MASK
59#define PAGE_CACHE_ALIGN(addr) (((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK)
60
61#define page_cache_get(page) get_page(page)
62#define page_cache_release(page) put_page(page)
63void release_pages(struct page **pages, int nr, int cold);
64
Paul Jackson44110fe2006-03-24 03:16:04 -080065#ifdef CONFIG_NUMA
Nick Piggin2ae88142006-10-28 10:38:23 -070066extern struct page *__page_cache_alloc(gfp_t gfp);
Paul Jackson44110fe2006-03-24 03:16:04 -080067#else
Nick Piggin2ae88142006-10-28 10:38:23 -070068static inline struct page *__page_cache_alloc(gfp_t gfp)
69{
70 return alloc_pages(gfp, 0);
71}
72#endif
73
Linus Torvalds1da177e2005-04-16 15:20:36 -070074static inline struct page *page_cache_alloc(struct address_space *x)
75{
Nick Piggin2ae88142006-10-28 10:38:23 -070076 return __page_cache_alloc(mapping_gfp_mask(x));
Linus Torvalds1da177e2005-04-16 15:20:36 -070077}
78
79static inline struct page *page_cache_alloc_cold(struct address_space *x)
80{
Nick Piggin2ae88142006-10-28 10:38:23 -070081 return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_COLD);
Linus Torvalds1da177e2005-04-16 15:20:36 -070082}
83
84typedef int filler_t(void *, struct page *);
85
86extern struct page * find_get_page(struct address_space *mapping,
Fengguang Wu57f6b962007-10-16 01:24:37 -070087 pgoff_t index);
Linus Torvalds1da177e2005-04-16 15:20:36 -070088extern struct page * find_lock_page(struct address_space *mapping,
Fengguang Wu57f6b962007-10-16 01:24:37 -070089 pgoff_t index);
Linus Torvalds1da177e2005-04-16 15:20:36 -070090extern struct page * find_or_create_page(struct address_space *mapping,
Fengguang Wu57f6b962007-10-16 01:24:37 -070091 pgoff_t index, gfp_t gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -070092unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
93 unsigned int nr_pages, struct page **pages);
Jens Axboeebf43502006-04-27 08:46:01 +020094unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
95 unsigned int nr_pages, struct page **pages);
Linus Torvalds1da177e2005-04-16 15:20:36 -070096unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
97 int tag, unsigned int nr_pages, struct page **pages);
98
Nick Pigginafddba42007-10-16 01:25:01 -070099struct page *__grab_cache_page(struct address_space *mapping, pgoff_t index);
100
Linus Torvalds1da177e2005-04-16 15:20:36 -0700101/*
102 * Returns locked page at given index in given cache, creating it if needed.
103 */
Fengguang Wu57f6b962007-10-16 01:24:37 -0700104static inline struct page *grab_cache_page(struct address_space *mapping,
105 pgoff_t index)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700106{
107 return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
108}
109
110extern struct page * grab_cache_page_nowait(struct address_space *mapping,
Fengguang Wu57f6b962007-10-16 01:24:37 -0700111 pgoff_t index);
Nick Piggin6fe69002007-05-06 14:49:04 -0700112extern struct page * read_cache_page_async(struct address_space *mapping,
Fengguang Wu57f6b962007-10-16 01:24:37 -0700113 pgoff_t index, filler_t *filler,
Nick Piggin6fe69002007-05-06 14:49:04 -0700114 void *data);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700115extern struct page * read_cache_page(struct address_space *mapping,
Fengguang Wu57f6b962007-10-16 01:24:37 -0700116 pgoff_t index, filler_t *filler,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 void *data);
118extern int read_cache_pages(struct address_space *mapping,
119 struct list_head *pages, filler_t *filler, void *data);
120
Nick Piggin6fe69002007-05-06 14:49:04 -0700121static inline struct page *read_mapping_page_async(
122 struct address_space *mapping,
Fengguang Wu57f6b962007-10-16 01:24:37 -0700123 pgoff_t index, void *data)
Nick Piggin6fe69002007-05-06 14:49:04 -0700124{
125 filler_t *filler = (filler_t *)mapping->a_ops->readpage;
126 return read_cache_page_async(mapping, index, filler, data);
127}
128
Pekka Enberg090d2b12006-06-23 02:05:08 -0700129static inline struct page *read_mapping_page(struct address_space *mapping,
Fengguang Wu57f6b962007-10-16 01:24:37 -0700130 pgoff_t index, void *data)
Pekka Enberg090d2b12006-06-23 02:05:08 -0700131{
132 filler_t *filler = (filler_t *)mapping->a_ops->readpage;
133 return read_cache_page(mapping, index, filler, data);
134}
135
Linus Torvalds1da177e2005-04-16 15:20:36 -0700136int add_to_page_cache(struct page *page, struct address_space *mapping,
Fengguang Wu57f6b962007-10-16 01:24:37 -0700137 pgoff_t index, gfp_t gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700138int add_to_page_cache_lru(struct page *page, struct address_space *mapping,
Fengguang Wu57f6b962007-10-16 01:24:37 -0700139 pgoff_t index, gfp_t gfp_mask);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700140extern void remove_from_page_cache(struct page *page);
141extern void __remove_from_page_cache(struct page *page);
142
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143/*
144 * Return byte-offset into filesystem object for page.
145 */
146static inline loff_t page_offset(struct page *page)
147{
148 return ((loff_t)page->index) << PAGE_CACHE_SHIFT;
149}
150
151static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
152 unsigned long address)
153{
154 pgoff_t pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
155 pgoff += vma->vm_pgoff;
156 return pgoff >> (PAGE_CACHE_SHIFT - PAGE_SHIFT);
157}
158
Harvey Harrisonb3c97522008-02-13 15:03:15 -0800159extern void __lock_page(struct page *page);
160extern int __lock_page_killable(struct page *page);
161extern void __lock_page_nosync(struct page *page);
162extern void unlock_page(struct page *page);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163
Nick Piggindb376482006-09-25 23:31:24 -0700164/*
165 * lock_page may only be called if we have the page's inode pinned.
166 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700167static inline void lock_page(struct page *page)
168{
169 might_sleep();
170 if (TestSetPageLocked(page))
171 __lock_page(page);
172}
Nick Piggindb376482006-09-25 23:31:24 -0700173
174/*
Matthew Wilcox2687a352007-12-06 11:18:49 -0500175 * lock_page_killable is like lock_page but can be interrupted by fatal
176 * signals. It returns 0 if it locked the page and -EINTR if it was
177 * killed while waiting.
178 */
179static inline int lock_page_killable(struct page *page)
180{
181 might_sleep();
182 if (TestSetPageLocked(page))
183 return __lock_page_killable(page);
184 return 0;
185}
186
187/*
Nick Piggindb376482006-09-25 23:31:24 -0700188 * lock_page_nosync should only be used if we can't pin the page's inode.
189 * Doesn't play quite so well with block device plugging.
190 */
191static inline void lock_page_nosync(struct page *page)
192{
193 might_sleep();
194 if (TestSetPageLocked(page))
195 __lock_page_nosync(page);
196}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700197
198/*
199 * This is exported only for wait_on_page_locked/wait_on_page_writeback.
200 * Never use this directly!
201 */
Harvey Harrisonb3c97522008-02-13 15:03:15 -0800202extern void wait_on_page_bit(struct page *page, int bit_nr);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700203
204/*
205 * Wait for a page to be unlocked.
206 *
207 * This must be called with the caller "holding" the page,
208 * ie with increased "page->count" so that the page won't
209 * go away during the wait..
210 */
211static inline void wait_on_page_locked(struct page *page)
212{
213 if (PageLocked(page))
214 wait_on_page_bit(page, PG_locked);
215}
216
217/*
218 * Wait for a page to complete writeback
219 */
220static inline void wait_on_page_writeback(struct page *page)
221{
222 if (PageWriteback(page))
223 wait_on_page_bit(page, PG_writeback);
224}
225
226extern void end_page_writeback(struct page *page);
227
228/*
229 * Fault a userspace page into pagetables. Return non-zero on a fault.
230 *
231 * This assumes that two userspace pages are always sufficient. That's
232 * not true if PAGE_CACHE_SIZE > PAGE_SIZE.
233 */
234static inline int fault_in_pages_writeable(char __user *uaddr, int size)
235{
236 int ret;
237
Nick Piggin08291422007-10-16 01:24:59 -0700238 if (unlikely(size == 0))
239 return 0;
240
Linus Torvalds1da177e2005-04-16 15:20:36 -0700241 /*
242 * Writing zeroes into userspace here is OK, because we know that if
243 * the zero gets there, we'll be overwriting it.
244 */
245 ret = __put_user(0, uaddr);
246 if (ret == 0) {
247 char __user *end = uaddr + size - 1;
248
249 /*
250 * If the page was already mapped, this will get a cache miss
251 * for sure, so try to avoid doing it.
252 */
253 if (((unsigned long)uaddr & PAGE_MASK) !=
254 ((unsigned long)end & PAGE_MASK))
255 ret = __put_user(0, end);
256 }
257 return ret;
258}
259
Nick Piggin08291422007-10-16 01:24:59 -0700260static inline int fault_in_pages_readable(const char __user *uaddr, int size)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261{
262 volatile char c;
263 int ret;
264
Nick Piggin08291422007-10-16 01:24:59 -0700265 if (unlikely(size == 0))
266 return 0;
267
Linus Torvalds1da177e2005-04-16 15:20:36 -0700268 ret = __get_user(c, uaddr);
269 if (ret == 0) {
270 const char __user *end = uaddr + size - 1;
271
272 if (((unsigned long)uaddr & PAGE_MASK) !=
273 ((unsigned long)end & PAGE_MASK))
Nick Piggin08291422007-10-16 01:24:59 -0700274 ret = __get_user(c, end);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275 }
Nick Piggin08291422007-10-16 01:24:59 -0700276 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700277}
278
279#endif /* _LINUX_PAGEMAP_H */