[deliverable/linux.git] / include / linux / pagemap.h

#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(gfp_t gfp);
#else
static inline struct page *__page_cache_alloc(gfp_t gfp)
{
	return alloc_pages(gfp, 0);
}
#endif

static inline struct page *page_cache_alloc(struct address_space *x)
{
	return __page_cache_alloc(mapping_gfp_mask(x));
}

static inline struct page *page_cache_alloc_cold(struct address_space *x)
{
	return __page_cache_alloc(mapping_gfp_mask(x)|__GFP_COLD);
}

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 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(__lock_page_nosync(struct page *page));
extern void FASTCALL(unlock_page(struct page *page));

/*
 * lock_page may only be called if we have the page's inode pinned.
 */
static inline void lock_page(struct page *page)
{
	might_sleep();
	if (TestSetPageLocked(page))
		__lock_page(page);
}

/*
 * lock_page_nosync should only be used if we can't pin the page's inode.
 * Doesn't play quite so well with block device plugging.
 */
static inline void lock_page_nosync(struct page *page)
{
	might_sleep();
	if (TestSetPageLocked(page))
		__lock_page_nosync(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 */
Commit	Line	Data
1da177e4 LT	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
dd0fc66f	22	static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
1da177e4	23	{
260b2367	24	return (__force gfp_t)mapping->flags & __GFP_BITS_MASK;
1da177e4 LT	25	}
	26
	27	/*
	28	* This is non-atomic. Only to be used before the mapping is activated.
	29	* Probably needs a barrier...
	30	*/
260b2367	31	static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
1da177e4	32	{
260b2367 AV	33	m->flags = (m->flags & ~(__force unsigned long)__GFP_BITS_MASK) \|
260b2367 AV	34	(__force unsigned long)mask;
1da177e4 LT	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
44110fe3	54	#ifdef CONFIG_NUMA
2ae88149	55	extern struct page *__page_cache_alloc(gfp_t gfp);
44110fe3	56	#else
2ae88149 NP	57	static inline struct page *__page_cache_alloc(gfp_t gfp)
	58	{
	59	return alloc_pages(gfp, 0);
	60	}
	61	#endif
	62
1da177e4 LT	63	static inline struct page page_cache_alloc(struct address_space x)
1da177e4 LT	64	{
2ae88149	65	return __page_cache_alloc(mapping_gfp_mask(x));
1da177e4 LT	66	}
	67
	68	static inline struct page page_cache_alloc_cold(struct address_space x)
	69	{
2ae88149	70	return __page_cache_alloc(mapping_gfp_mask(x)\|__GFP_COLD);
1da177e4 LT	71	}
	72
	73	typedef int filler_t(void , struct page );
	74
	75	extern struct page * find_get_page(struct address_space *mapping,
	76	unsigned long index);
	77	extern struct page * find_lock_page(struct address_space *mapping,
	78	unsigned long index);
1da177e4	79	extern struct page * find_or_create_page(struct address_space *mapping,
6daa0e28	80	unsigned long index, gfp_t gfp_mask);
1da177e4 LT	81	unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
1da177e4 LT	82	unsigned int nr_pages, struct page **pages);
ebf43500 JA	83	unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
ebf43500 JA	84	unsigned int nr_pages, struct page **pages);
1da177e4 LT	85	unsigned find_get_pages_tag(struct address_space mapping, pgoff_t index,
	86	int tag, unsigned int nr_pages, struct page **pages);
	87
	88	/*
	89	* Returns locked page at given index in given cache, creating it if needed.
	90	*/
	91	static inline struct page grab_cache_page(struct address_space mapping, unsigned long index)
	92	{
	93	return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
	94	}
	95
	96	extern struct page * grab_cache_page_nowait(struct address_space *mapping,
	97	unsigned long index);
	98	extern struct page * read_cache_page(struct address_space *mapping,
	99	unsigned long index, filler_t *filler,
	100	void *data);
	101	extern int read_cache_pages(struct address_space *mapping,
	102	struct list_head pages, filler_t filler, void *data);
	103
090d2b18 PE	104	static inline struct page read_mapping_page(struct address_space mapping,
	105	unsigned long index, void *data)
	106	{
	107	filler_t filler = (filler_t )mapping->a_ops->readpage;
	108	return read_cache_page(mapping, index, filler, data);
	109	}
	110
1da177e4	111	int add_to_page_cache(struct page page, struct address_space mapping,
6daa0e28	112	unsigned long index, gfp_t gfp_mask);
1da177e4	113	int add_to_page_cache_lru(struct page page, struct address_space mapping,
6daa0e28	114	unsigned long index, gfp_t gfp_mask);
1da177e4 LT	115	extern void remove_from_page_cache(struct page *page);
	116	extern void __remove_from_page_cache(struct page *page);
	117
1da177e4 LT	118	/*
	119	* Return byte-offset into filesystem object for page.
	120	*/
	121	static inline loff_t page_offset(struct page *page)
	122	{
	123	return ((loff_t)page->index) << PAGE_CACHE_SHIFT;
	124	}
	125
	126	static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
	127	unsigned long address)
	128	{
	129	pgoff_t pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
	130	pgoff += vma->vm_pgoff;
	131	return pgoff >> (PAGE_CACHE_SHIFT - PAGE_SHIFT);
	132	}
	133
	134	extern void FASTCALL(__lock_page(struct page *page));
db37648c	135	extern void FASTCALL(__lock_page_nosync(struct page *page));
1da177e4 LT	136	extern void FASTCALL(unlock_page(struct page *page));
1da177e4 LT	137
db37648c NP	138	/*
	139	* lock_page may only be called if we have the page's inode pinned.
	140	*/
1da177e4 LT	141	static inline void lock_page(struct page *page)
	142	{
	143	might_sleep();
	144	if (TestSetPageLocked(page))
	145	__lock_page(page);
	146	}
db37648c NP	147
	148	/*
	149	* lock_page_nosync should only be used if we can't pin the page's inode.
	150	* Doesn't play quite so well with block device plugging.
	151	*/
	152	static inline void lock_page_nosync(struct page *page)
	153	{
	154	might_sleep();
	155	if (TestSetPageLocked(page))
	156	__lock_page_nosync(page);
	157	}
1da177e4 LT	158
	159	/*
	160	* This is exported only for wait_on_page_locked/wait_on_page_writeback.
	161	* Never use this directly!
	162	*/
	163	extern void FASTCALL(wait_on_page_bit(struct page *page, int bit_nr));
	164
	165	/*
	166	* Wait for a page to be unlocked.
	167	*
	168	* This must be called with the caller "holding" the page,
	169	* ie with increased "page->count" so that the page won't
	170	* go away during the wait..
	171	*/
	172	static inline void wait_on_page_locked(struct page *page)
	173	{
	174	if (PageLocked(page))
	175	wait_on_page_bit(page, PG_locked);
	176	}
	177
	178	/*
	179	* Wait for a page to complete writeback
	180	*/
	181	static inline void wait_on_page_writeback(struct page *page)
	182	{
	183	if (PageWriteback(page))
	184	wait_on_page_bit(page, PG_writeback);
	185	}
	186
	187	extern void end_page_writeback(struct page *page);
	188
	189	/*
	190	* Fault a userspace page into pagetables. Return non-zero on a fault.
	191	*
	192	* This assumes that two userspace pages are always sufficient. That's
	193	* not true if PAGE_CACHE_SIZE > PAGE_SIZE.
	194	*/
	195	static inline int fault_in_pages_writeable(char __user *uaddr, int size)
	196	{
	197	int ret;
	198
	199	/*
	200	* Writing zeroes into userspace here is OK, because we know that if
	201	* the zero gets there, we'll be overwriting it.
	202	*/
	203	ret = __put_user(0, uaddr);
	204	if (ret == 0) {
	205	char __user *end = uaddr + size - 1;
	206
	207	/*
	208	* If the page was already mapped, this will get a cache miss
	209	* for sure, so try to avoid doing it.
	210	*/
	211	if (((unsigned long)uaddr & PAGE_MASK) !=
	212	((unsigned long)end & PAGE_MASK))
	213	ret = __put_user(0, end);
	214	}
	215	return ret;
	216	}
	217
	218	static inline void fault_in_pages_readable(const char __user *uaddr, int size)
	219	{
	220	volatile char c;
	221	int ret;
222
223	ret = __get_user(c, uaddr);
224	if (ret == 0) {
225	const char __user *end = uaddr + size - 1;
226
227	if (((unsigned long)uaddr & PAGE_MASK) !=
228	((unsigned long)end & PAGE_MASK))
229	__get_user(c, end);
230	}
231	}
232
233	#endif /* _LINUX_PAGEMAP_H */