[linux-block.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>
#include <linux/bitops.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 void mapping_set_error(struct address_space *mapping, int error)
{
	if (error) {
		if (error == -ENOSPC)
			set_bit(AS_ENOSPC, &mapping->flags);
		else
			set_bit(AS_EIO, &mapping->flags);
	}
}

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_async(struct address_space *mapping,
				unsigned long index, filler_t *filler,
				void *data);
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_async(
						struct address_space *mapping,
					     unsigned long index, void *data)
{
	filler_t *filler = (filler_t *)mapping->a_ops->readpage;
	return read_cache_page_async(mapping, index, filler, 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>
3e9f45bd	14	#include <linux/bitops.h>
1da177e4 LT	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
3e9f45bd GC	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
dd0fc66f	33	static inline gfp_t mapping_gfp_mask(struct address_space * mapping)
1da177e4	34	{
260b2367	35	return (__force gfp_t)mapping->flags & __GFP_BITS_MASK;
1da177e4 LT	36	}
	37
	38	/*
	39	* This is non-atomic. Only to be used before the mapping is activated.
	40	* Probably needs a barrier...
	41	*/
260b2367	42	static inline void mapping_set_gfp_mask(struct address_space *m, gfp_t mask)
1da177e4	43	{
260b2367 AV	44	m->flags = (m->flags & ~(__force unsigned long)__GFP_BITS_MASK) \|
260b2367 AV	45	(__force unsigned long)mask;
1da177e4 LT	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
44110fe3	65	#ifdef CONFIG_NUMA
2ae88149	66	extern struct page *__page_cache_alloc(gfp_t gfp);
44110fe3	67	#else
2ae88149 NP	68	static inline struct page *__page_cache_alloc(gfp_t gfp)
	69	{
	70	return alloc_pages(gfp, 0);
	71	}
	72	#endif
	73
1da177e4 LT	74	static inline struct page page_cache_alloc(struct address_space x)
1da177e4 LT	75	{
2ae88149	76	return __page_cache_alloc(mapping_gfp_mask(x));
1da177e4 LT	77	}
	78
	79	static inline struct page page_cache_alloc_cold(struct address_space x)
	80	{
2ae88149	81	return __page_cache_alloc(mapping_gfp_mask(x)\|__GFP_COLD);
1da177e4 LT	82	}
	83
	84	typedef int filler_t(void , struct page );
	85
	86	extern struct page * find_get_page(struct address_space *mapping,
	87	unsigned long index);
	88	extern struct page * find_lock_page(struct address_space *mapping,
	89	unsigned long index);
1da177e4	90	extern struct page * find_or_create_page(struct address_space *mapping,
6daa0e28	91	unsigned long index, gfp_t gfp_mask);
1da177e4 LT	92	unsigned find_get_pages(struct address_space *mapping, pgoff_t start,
1da177e4 LT	93	unsigned int nr_pages, struct page **pages);
ebf43500 JA	94	unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
ebf43500 JA	95	unsigned int nr_pages, struct page **pages);
1da177e4 LT	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	/*
	100	* Returns locked page at given index in given cache, creating it if needed.
	101	*/
	102	static inline struct page grab_cache_page(struct address_space mapping, unsigned long index)
	103	{
	104	return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));
	105	}
	106
	107	extern struct page * grab_cache_page_nowait(struct address_space *mapping,
	108	unsigned long index);
6fe6900e NP	109	extern struct page * read_cache_page_async(struct address_space *mapping,
	110	unsigned long index, filler_t *filler,
	111	void *data);
1da177e4 LT	112	extern struct page * read_cache_page(struct address_space *mapping,
	113	unsigned long index, filler_t *filler,
	114	void *data);
	115	extern int read_cache_pages(struct address_space *mapping,
	116	struct list_head pages, filler_t filler, void *data);
	117
6fe6900e NP	118	static inline struct page *read_mapping_page_async(
	119	struct address_space *mapping,
	120	unsigned long index, void *data)
	121	{
	122	filler_t filler = (filler_t )mapping->a_ops->readpage;
	123	return read_cache_page_async(mapping, index, filler, data);
	124	}
	125
090d2b18 PE	126	static inline struct page read_mapping_page(struct address_space mapping,
	127	unsigned long index, void *data)
	128	{
	129	filler_t filler = (filler_t )mapping->a_ops->readpage;
	130	return read_cache_page(mapping, index, filler, data);
	131	}
	132
1da177e4	133	int add_to_page_cache(struct page page, struct address_space mapping,
6daa0e28	134	unsigned long index, gfp_t gfp_mask);
1da177e4	135	int add_to_page_cache_lru(struct page page, struct address_space mapping,
6daa0e28	136	unsigned long index, gfp_t gfp_mask);
1da177e4 LT	137	extern void remove_from_page_cache(struct page *page);
	138	extern void __remove_from_page_cache(struct page *page);
	139
1da177e4 LT	140	/*
	141	* Return byte-offset into filesystem object for page.
	142	*/
	143	static inline loff_t page_offset(struct page *page)
	144	{
	145	return ((loff_t)page->index) << PAGE_CACHE_SHIFT;
	146	}
	147
	148	static inline pgoff_t linear_page_index(struct vm_area_struct *vma,
	149	unsigned long address)
	150	{
	151	pgoff_t pgoff = (address - vma->vm_start) >> PAGE_SHIFT;
	152	pgoff += vma->vm_pgoff;
	153	return pgoff >> (PAGE_CACHE_SHIFT - PAGE_SHIFT);
	154	}
	155
	156	extern void FASTCALL(__lock_page(struct page *page));
db37648c	157	extern void FASTCALL(__lock_page_nosync(struct page *page));
1da177e4 LT	158	extern void FASTCALL(unlock_page(struct page *page));
1da177e4 LT	159
db37648c NP	160	/*
	161	* lock_page may only be called if we have the page's inode pinned.
	162	*/
1da177e4 LT	163	static inline void lock_page(struct page *page)
	164	{
	165	might_sleep();
	166	if (TestSetPageLocked(page))
	167	__lock_page(page);
	168	}
db37648c NP	169
	170	/*
	171	* lock_page_nosync should only be used if we can't pin the page's inode.
	172	* Doesn't play quite so well with block device plugging.
	173	*/
	174	static inline void lock_page_nosync(struct page *page)
	175	{
	176	might_sleep();
	177	if (TestSetPageLocked(page))
	178	__lock_page_nosync(page);
	179	}
1da177e4 LT	180
	181	/*
	182	* This is exported only for wait_on_page_locked/wait_on_page_writeback.
	183	* Never use this directly!
	184	*/
	185	extern void FASTCALL(wait_on_page_bit(struct page *page, int bit_nr));
	186
	187	/*
	188	* Wait for a page to be unlocked.
	189	*
	190	* This must be called with the caller "holding" the page,
	191	* ie with increased "page->count" so that the page won't
	192	* go away during the wait..
	193	*/
	194	static inline void wait_on_page_locked(struct page *page)
	195	{
	196	if (PageLocked(page))
	197	wait_on_page_bit(page, PG_locked);
	198	}
	199
	200	/*
	201	* Wait for a page to complete writeback
	202	*/
	203	static inline void wait_on_page_writeback(struct page *page)
	204	{
	205	if (PageWriteback(page))
	206	wait_on_page_bit(page, PG_writeback);
	207	}
	208
	209	extern void end_page_writeback(struct page *page);
	210
	211	/*
	212	* Fault a userspace page into pagetables. Return non-zero on a fault.
	213	*
	214	* This assumes that two userspace pages are always sufficient. That's
	215	* not true if PAGE_CACHE_SIZE > PAGE_SIZE.
	216	*/
	217	static inline int fault_in_pages_writeable(char __user *uaddr, int size)
	218	{
	219	int ret;
	220
	221	/*
	222	* Writing zeroes into userspace here is OK, because we know that if
	223	* the zero gets there, we'll be overwriting it.
	224	*/
	225	ret = __put_user(0, uaddr);
	226	if (ret == 0) {
	227	char __user *end = uaddr + size - 1;
	228
	229	/*
	230	* If the page was already mapped, this will get a cache miss
	231	* for sure, so try to avoid doing it.
	232	*/
	233	if (((unsigned long)uaddr & PAGE_MASK) !=
	234	((unsigned long)end & PAGE_MASK))
	235	ret = __put_user(0, end);
	236	}
	237	return ret;
	238	}
	239
	240	static inline void fault_in_pages_readable(const char __user *uaddr, int size)
	241	{
	242	volatile char c;
	243	int ret;
244
245	ret = __get_user(c, uaddr);
246	if (ret == 0) {
247	const char __user *end = uaddr + size - 1;
248
249	if (((unsigned long)uaddr & PAGE_MASK) !=
250	((unsigned long)end & PAGE_MASK))
251	__get_user(c, end);
252	}
253	}
254
255	#endif /* _LINUX_PAGEMAP_H */