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#ifndef _LINUX_RMAP_H

#define _LINUX_RMAP_H

/*

 * Declarations for Reverse Mapping functions in mm/rmap.c

 */

#include <linux/list.h>

#include <linux/slab.h>

#include <linux/mm.h>

#include <linux/spinlock.h>

/*

 * The anon_vma heads a list of private "related" vmas, to scan if

 * an anonymous page pointing to this anon_vma needs to be unmapped:

 * the vmas on the list will be related by forking, or by splitting.

 *

 * Since vmas come and go as they are split and merged (particularly

 * in mprotect), the mapping field of an anonymous page cannot point

 * directly to a vma: instead it points to an anon_vma, on whose list

 * the related vmas can be easily linked or unlinked.

 *

 * After unlinking the last vma on the list, we must garbage collect

 * the anon_vma object itself: we're guaranteed no page can be

 * pointing to this anon_vma once its vma list is empty.

 */

struct anon_vma {

        spinlock_t lock;        /* Serialize access to vma list */

        struct list_head head;  /* List of private "related" vmas */

};

#ifdef CONFIG_MMU

extern struct kmem_cache *anon_vma_cachep;

static inline struct anon_vma *anon_vma_alloc(void)

{

        return kmem_cache_alloc(anon_vma_cachep, GFP_KERNEL);

}

static inline void anon_vma_free(struct anon_vma *anon_vma)

{

        kmem_cache_free(anon_vma_cachep, anon_vma);

}

static inline void anon_vma_lock(struct vm_area_struct *vma)

{

        struct anon_vma *anon_vma = vma->anon_vma;

        if (anon_vma)

                spin_lock(&anon_vma->lock);

}

static inline void anon_vma_unlock(struct vm_area_struct *vma)

{

        struct anon_vma *anon_vma = vma->anon_vma;

        if (anon_vma)

                spin_unlock(&anon_vma->lock);

}

/*

 * anon_vma helper functions.

 */

void anon_vma_init(void);       /* create anon_vma_cachep */

int  anon_vma_prepare(struct vm_area_struct *);

void __anon_vma_merge(struct vm_area_struct *, struct vm_area_struct *);

void anon_vma_unlink(struct vm_area_struct *);

void anon_vma_link(struct vm_area_struct *);

void __anon_vma_link(struct vm_area_struct *);

/*

 * rmap interfaces called when adding or removing pte of page

 */

void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);

void page_add_new_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);

void page_add_file_rmap(struct page *);

void page_remove_rmap(struct page *, struct vm_area_struct *);

#ifdef CONFIG_DEBUG_VM

void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address);

#else

static inline void page_dup_rmap(struct page *page, struct vm_area_struct *vma, unsigned long address)

{

        atomic_inc(&page->_mapcount);

}

#endif

/*

 * Called from mm/vmscan.c to handle paging out

 */

int page_referenced(struct page *, int is_locked);

int try_to_unmap(struct page *, int ignore_refs);

/*

 * Called from mm/filemap_xip.c to unmap empty zero page

 */

pte_t *page_check_address(struct page *, struct mm_struct *,

                                unsigned long, spinlock_t **);

/*

 * Used by swapoff to help locate where page is expected in vma.

 */

unsigned long page_address_in_vma(struct page *, struct vm_area_struct *);

/*

 * Cleans the PTEs of shared mappings.

 * (and since clean PTEs should also be readonly, write protects them too)

 *

 * returns the number of cleaned PTEs.

 */

int page_mkclean(struct page *);

#else   /* !CONFIG_MMU */

#define anon_vma_init()         do {} while (0)

#define anon_vma_prepare(vma)   (0)

#define anon_vma_link(vma)      do {} while (0)

#define page_referenced(page,l) TestClearPageReferenced(page)

#define try_to_unmap(page, refs) SWAP_FAIL

static inline int page_mkclean(struct page *page)

{

        return 0;

}

#endif  /* CONFIG_MMU */

/*

 * Return values of try_to_unmap

 */

#define SWAP_SUCCESS    0

#define SWAP_AGAIN      1

#define SWAP_FAIL       2

#endif  /* _LINUX_RMAP_H */