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#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,

                                pgoff_t index);

extern struct page * find_lock_page(struct address_space *mapping,

                                pgoff_t index);

extern struct page * find_or_create_page(struct address_space *mapping,

                                pgoff_t 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);

struct page *__grab_cache_page(struct address_space *mapping, pgoff_t index);

/*

 * Returns locked page at given index in given cache, creating it if needed.

 */

static inline struct page *grab_cache_page(struct address_space *mapping,

                                                                pgoff_t index)

{

        return find_or_create_page(mapping, index, mapping_gfp_mask(mapping));

}

extern struct page * grab_cache_page_nowait(struct address_space *mapping,

                                pgoff_t index);

extern struct page * read_cache_page_async(struct address_space *mapping,

                                pgoff_t index, filler_t *filler,

                                void *data);

extern struct page * read_cache_page(struct address_space *mapping,

                                pgoff_t 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,

                                                     pgoff_t 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,

                                             pgoff_t 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,

                                pgoff_t index, gfp_t gfp_mask);

int add_to_page_cache_lru(struct page *page, struct address_space *mapping,

                                pgoff_t 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;

        if (unlikely(size == 0))

                return 0;

        /*

         * 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 int fault_in_pages_readable(const char __user *uaddr, int size)

{

        volatile char c;

        int ret;

        if (unlikely(size == 0))

                return 0;

        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))

                        ret = __get_user(c, end);

        }

        return ret;

}

#endif /* _LINUX_PAGEMAP_H */