| #ifndef _LINUX_PAGEMAP_H |
| #define _LINUX_PAGEMAP_H |
| |
| /* |
| * Copyright 1995 Linus Torvalds |
| */ |
| #include <linux/mm.h> |
| #include <linux/fs.h> |
| #include <linux/list.h> |
| #include <linux/highmem.h> |
| #include <linux/compiler.h> |
| #include <asm/uaccess.h> |
| #include <linux/gfp.h> |
| |
| /* |
| * Bits in mapping->flags. The lower __GFP_BITS_SHIFT bits are the page |
| * allocation mode flags. |
| */ |
| #define AS_EIO (__GFP_BITS_SHIFT + 0) /* IO error on async write */ |
| #define AS_ENOSPC (__GFP_BITS_SHIFT + 1) /* ENOSPC on async write */ |
| |
| static inline gfp_t mapping_gfp_mask(struct address_space * mapping) |
| { |
| return (__force gfp_t)mapping->flags & __GFP_BITS_MASK; |
| } |
| |
| /* |
| * This is non-atomic. Only to be used before the mapping is activated. |
| * Probably needs a barrier... |
| */ |
| static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask) |
| { |
| m->flags = (m->flags & ~(__force unsigned long)__GFP_BITS_MASK) | |
| (__force unsigned long)mask; |
| } |
| |
| /* |
| * The page cache can done in larger chunks than |
| * one page, because it allows for more efficient |
| * throughput (it can then be mapped into user |
| * space in smaller chunks for same flexibility). |
| * |
| * Or rather, it _will_ be done in larger chunks. |
| */ |
| #define PAGE_CACHE_SHIFT PAGE_SHIFT |
| #define PAGE_CACHE_SIZE PAGE_SIZE |
| #define PAGE_CACHE_MASK PAGE_MASK |
| #define PAGE_CACHE_ALIGN(addr) (((addr)+PAGE_CACHE_SIZE-1)&PAGE_CACHE_MASK) |
| |
| #define page_cache_get(page) get_page(page) |
| #define page_cache_release(page) put_page(page) |
| void release_pages(struct page **pages, int nr, int cold); |
| |
| #ifdef CONFIG_NUMA |
| extern struct page *page_cache_alloc(struct address_space *x); |
| extern struct page *page_cache_alloc_cold(struct address_space *x); |
| #else |
| static inline struct page *page_cache_alloc(struct address_space *x) |
| { |
| return alloc_pages(mapping_gfp_mask(x), 0); |
| } |
| |
| static inline struct page *page_cache_alloc_cold(struct address_space *x) |
| { |
| return alloc_pages(mapping_gfp_mask(x)|__GFP_COLD, 0); |
| } |
| #endif |
| |
| typedef int filler_t(void *, struct page *); |
| |
| extern struct page * find_get_page(struct address_space *mapping, |
| unsigned long index); |
| extern struct page * find_lock_page(struct address_space *mapping, |
| unsigned long index); |
| extern __deprecated_for_modules struct page * find_trylock_page( |
| struct address_space *mapping, unsigned long index); |
| extern struct page * find_or_create_page(struct address_space *mapping, |
| unsigned long index, gfp_t gfp_mask); |
| unsigned find_get_pages(struct address_space *mapping, pgoff_t start, |
| unsigned int nr_pages, struct page **pages); |
| unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start, |
| unsigned int nr_pages, struct page **pages); |
| unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index, |
| int tag, unsigned int nr_pages, struct page **pages); |
| |
| /* |
| * Returns locked page at given index in given cache, creating it if needed. |
| */ |
| static inline struct page *grab_cache_page(struct address_space *mapping, unsigned long index) |
| { |
| return find_or_create_page(mapping, index, mapping_gfp_mask(mapping)); |
| } |
| |
| extern struct page * grab_cache_page_nowait(struct address_space *mapping, |
| unsigned long index); |
| extern struct page * read_cache_page(struct address_space *mapping, |
| unsigned long index, filler_t *filler, |
| void *data); |
| extern int read_cache_pages(struct address_space *mapping, |
| struct list_head *pages, filler_t *filler, void *data); |
| |
| static inline struct page *read_mapping_page(struct address_space *mapping, |
| unsigned long index, void *data) |
| { |
| filler_t *filler = (filler_t *)mapping->a_ops->readpage; |
| return read_cache_page(mapping, index, filler, data); |
| } |
| |
| int add_to_page_cache(struct page *page, struct address_space *mapping, |
| unsigned long index, gfp_t gfp_mask); |
| int add_to_page_cache_lru(struct page *page, struct address_space *mapping, |
| unsigned long index, gfp_t gfp_mask); |
| extern void remove_from_page_cache(struct page *page); |
| extern void __remove_from_page_cache(struct page *page); |
| |
| /* |
| * Return byte-offset into filesystem object for page. |
| */ |
| static inline loff_t page_offset(struct page *page) |
| { |
| return ((loff_t)page->index) << PAGE_CACHE_SHIFT; |
| } |
| |
| static inline pgoff_t linear_page_index(struct vm_area_struct *vma, |
| unsigned long address) |
| { |
| pgoff_t pgoff = (address - vma->vm_start) >> PAGE_SHIFT; |
| pgoff += vma->vm_pgoff; |
| return pgoff >> (PAGE_CACHE_SHIFT - PAGE_SHIFT); |
| } |
| |
| extern void FASTCALL(__lock_page(struct page *page)); |
| extern void FASTCALL(unlock_page(struct page *page)); |
| |
| static inline void lock_page(struct page *page) |
| { |
| might_sleep(); |
| if (TestSetPageLocked(page)) |
| __lock_page(page); |
| } |
| |
| /* |
| * This is exported only for wait_on_page_locked/wait_on_page_writeback. |
| * Never use this directly! |
| */ |
| extern void FASTCALL(wait_on_page_bit(struct page *page, int bit_nr)); |
| |
| /* |
| * Wait for a page to be unlocked. |
| * |
| * This must be called with the caller "holding" the page, |
| * ie with increased "page->count" so that the page won't |
| * go away during the wait.. |
| */ |
| static inline void wait_on_page_locked(struct page *page) |
| { |
| if (PageLocked(page)) |
| wait_on_page_bit(page, PG_locked); |
| } |
| |
| /* |
| * Wait for a page to complete writeback |
| */ |
| static inline void wait_on_page_writeback(struct page *page) |
| { |
| if (PageWriteback(page)) |
| wait_on_page_bit(page, PG_writeback); |
| } |
| |
| extern void end_page_writeback(struct page *page); |
| |
| /* |
| * Fault a userspace page into pagetables. Return non-zero on a fault. |
| * |
| * This assumes that two userspace pages are always sufficient. That's |
| * not true if PAGE_CACHE_SIZE > PAGE_SIZE. |
| */ |
| static inline int fault_in_pages_writeable(char __user *uaddr, int size) |
| { |
| int ret; |
| |
| /* |
| * Writing zeroes into userspace here is OK, because we know that if |
| * the zero gets there, we'll be overwriting it. |
| */ |
| ret = __put_user(0, uaddr); |
| if (ret == 0) { |
| char __user *end = uaddr + size - 1; |
| |
| /* |
| * If the page was already mapped, this will get a cache miss |
| * for sure, so try to avoid doing it. |
| */ |
| if (((unsigned long)uaddr & PAGE_MASK) != |
| ((unsigned long)end & PAGE_MASK)) |
| ret = __put_user(0, end); |
| } |
| return ret; |
| } |
| |
| static inline void fault_in_pages_readable(const char __user *uaddr, int size) |
| { |
| volatile char c; |
| int ret; |
| |
| ret = __get_user(c, uaddr); |
| if (ret == 0) { |
| const char __user *end = uaddr + size - 1; |
| |
| if (((unsigned long)uaddr & PAGE_MASK) != |
| ((unsigned long)end & PAGE_MASK)) |
| __get_user(c, end); |
| } |
| } |
| |
| #endif /* _LINUX_PAGEMAP_H */ |