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 #include <linux/bitops.h> 15 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 23 static 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 33 static inline gfp_t mapping_gfp_mask(struct address_space * mapping) 34 { 35 return (__force gfp_t)mapping->flags & __GFP_BITS_MASK; 36 } 37 38 /* 39 * This is non-atomic. Only to be used before the mapping is activated. 40 * Probably needs a barrier... 41 */ 42 static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask) 43 { 44 m->flags = (m->flags & ~(__force unsigned long)__GFP_BITS_MASK) | 45 (__force unsigned long)mask; 46 } 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) 63 void release_pages(struct page **pages, int nr, int cold); 64 65 #ifdef CONFIG_NUMA 66 extern struct page *__page_cache_alloc(gfp_t gfp); 67 #else 68 static inline struct page *__page_cache_alloc(gfp_t gfp) 69 { 70 return alloc_pages(gfp, 0); 71 } 72 #endif 73 74 static inline struct page *page_cache_alloc(struct address_space *x) 75 { 76 return __page_cache_alloc(mapping_gfp_mask(x)); 77 } 78 79 static inline struct page *page_cache_alloc_cold(struct address_space *x) 80 { 81 return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_COLD); 82 } 83 84 typedef int filler_t(void *, struct page *); 85 86 extern struct page * find_get_page(struct address_space *mapping, 87 pgoff_t index); 88 extern struct page * find_lock_page(struct address_space *mapping, 89 pgoff_t index); 90 extern struct page * find_or_create_page(struct address_space *mapping, 91 pgoff_t index, gfp_t gfp_mask); 92 unsigned find_get_pages(struct address_space *mapping, pgoff_t start, 93 unsigned int nr_pages, struct page **pages); 94 unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start, 95 unsigned int nr_pages, struct page **pages); 96 unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, 97 int tag, unsigned int nr_pages, struct page **pages); 98 99 struct page *__grab_cache_page(struct address_space *mapping, pgoff_t index); 100 101 /* 102 * Returns locked page at given index in given cache, creating it if needed. 103 */ 104 static inline struct page *grab_cache_page(struct address_space *mapping, 105 pgoff_t index) 106 { 107 return find_or_create_page(mapping, index, mapping_gfp_mask(mapping)); 108 } 109 110 extern struct page * grab_cache_page_nowait(struct address_space *mapping, 111 pgoff_t index); 112 extern struct page * read_cache_page_async(struct address_space *mapping, 113 pgoff_t index, filler_t *filler, 114 void *data); 115 extern struct page * read_cache_page(struct address_space *mapping, 116 pgoff_t index, filler_t *filler, 117 void *data); 118 extern int read_cache_pages(struct address_space *mapping, 119 struct list_head *pages, filler_t *filler, void *data); 120 121 static inline struct page *read_mapping_page_async( 122 struct address_space *mapping, 123 pgoff_t index, void *data) 124 { 125 filler_t *filler = (filler_t *)mapping->a_ops->readpage; 126 return read_cache_page_async(mapping, index, filler, data); 127 } 128 129 static inline struct page *read_mapping_page(struct address_space *mapping, 130 pgoff_t index, void *data) 131 { 132 filler_t *filler = (filler_t *)mapping->a_ops->readpage; 133 return read_cache_page(mapping, index, filler, data); 134 } 135 136 int add_to_page_cache(struct page *page, struct address_space *mapping, 137 pgoff_t index, gfp_t gfp_mask); 138 int add_to_page_cache_lru(struct page *page, struct address_space *mapping, 139 pgoff_t index, gfp_t gfp_mask); 140 extern void remove_from_page_cache(struct page *page); 141 extern void __remove_from_page_cache(struct page *page); 142 143 /* 144 * Return byte-offset into filesystem object for page. 145 */ 146 static inline loff_t page_offset(struct page *page) 147 { 148 return ((loff_t)page->index) << PAGE_CACHE_SHIFT; 149 } 150 151 static 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 } 158 159 extern void FASTCALL(__lock_page(struct page *page)); 160 extern int FASTCALL(__lock_page_killable(struct page *page)); 161 extern void FASTCALL(__lock_page_nosync(struct page *page)); 162 extern void FASTCALL(unlock_page(struct page *page)); 163 164 /* 165 * lock_page may only be called if we have the page's inode pinned. 166 */ 167 static inline void lock_page(struct page *page) 168 { 169 might_sleep(); 170 if (TestSetPageLocked(page)) 171 __lock_page(page); 172 } 173 174 /* 175 * 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 */ 179 static 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 /* 188 * 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 */ 191 static inline void lock_page_nosync(struct page *page) 192 { 193 might_sleep(); 194 if (TestSetPageLocked(page)) 195 __lock_page_nosync(page); 196 } 197 198 /* 199 * This is exported only for wait_on_page_locked/wait_on_page_writeback. 200 * Never use this directly! 201 */ 202 extern void FASTCALL(wait_on_page_bit(struct page *page, int bit_nr)); 203 204 /* 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 */ 211 static 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 */ 220 static inline void wait_on_page_writeback(struct page *page) 221 { 222 if (PageWriteback(page)) 223 wait_on_page_bit(page, PG_writeback); 224 } 225 226 extern 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 */ 234 static inline int fault_in_pages_writeable(char __user *uaddr, int size) 235 { 236 int ret; 237 238 if (unlikely(size == 0)) 239 return 0; 240 241 /* 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 } 259 260 static inline int fault_in_pages_readable(const char __user *uaddr, int size) 261 { 262 volatile char c; 263 int ret; 264 265 if (unlikely(size == 0)) 266 return 0; 267 268 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)) 274 ret = __get_user(c, end); 275 } 276 return ret; 277 } 278 279 #endif /* _LINUX_PAGEMAP_H */ 280