include/linux/rmap.h - kernel/msm-4.9 - Gitiles

 #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/rwsem.h>
 #include <linux/memcontrol.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 {
 	struct anon_vma *root;		/* Root of this anon_vma tree */
 	struct rw_semaphore rwsem;	/* W: modification, R: walking the list */
 	/*
 	 * The refcount is taken on an anon_vma when there is no
 	 * guarantee that the vma of page tables will exist for
 	 * the duration of the operation. A caller that takes
 	 * the reference is responsible for clearing up the
 	 * anon_vma if they are the last user on release
 	 */
 	atomic_t refcount;

 	/*
 	 * NOTE: the LSB of the rb_root.rb_node is set by
 	 * mm_take_all_locks() _after_ taking the above lock. So the
 	 * rb_root must only be read/written after taking the above lock
 	 * to be sure to see a valid next pointer. The LSB bit itself
 	 * is serialized by a system wide lock only visible to
 	 * mm_take_all_locks() (mm_all_locks_mutex).
 	 */
 	struct rb_root rb_root;	/* Interval tree of private "related" vmas */
 };

 /*
  * The copy-on-write semantics of fork mean that an anon_vma
  * can become associated with multiple processes. Furthermore,
  * each child process will have its own anon_vma, where new
  * pages for that process are instantiated.
  *
  * This structure allows us to find the anon_vmas associated
  * with a VMA, or the VMAs associated with an anon_vma.
  * The "same_vma" list contains the anon_vma_chains linking
  * all the anon_vmas associated with this VMA.
  * The "rb" field indexes on an interval tree the anon_vma_chains
  * which link all the VMAs associated with this anon_vma.
  */
 struct anon_vma_chain {
 	struct vm_area_struct *vma;
 	struct anon_vma *anon_vma;
 	struct list_head same_vma;   /* locked by mmap_sem & page_table_lock */
 	struct rb_node rb;			/* locked by anon_vma->rwsem */
 	unsigned long rb_subtree_last;
 #ifdef CONFIG_DEBUG_VM_RB
 	unsigned long cached_vma_start, cached_vma_last;
 #endif
 };

 enum ttu_flags {
 	TTU_UNMAP = 0,			/* unmap mode */
 	TTU_MIGRATION = 1,		/* migration mode */
 	TTU_MUNLOCK = 2,		/* munlock mode */
 	TTU_ACTION_MASK = 0xff,

 	TTU_IGNORE_MLOCK = (1 << 8),	/* ignore mlock */
 	TTU_IGNORE_ACCESS = (1 << 9),	/* don't age */
 	TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
 };

 #ifdef CONFIG_MMU
 static inline void get_anon_vma(struct anon_vma *anon_vma)
 {
 	atomic_inc(&anon_vma->refcount);
 }

 void __put_anon_vma(struct anon_vma *anon_vma);

 static inline void put_anon_vma(struct anon_vma *anon_vma)
 {
 	if (atomic_dec_and_test(&anon_vma->refcount))
 		__put_anon_vma(anon_vma);
 }

 static inline struct anon_vma *page_anon_vma(struct page *page)
 {
 	if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) !=
 					    PAGE_MAPPING_ANON)
 		return NULL;
 	return page_rmapping(page);
 }

 static inline void vma_lock_anon_vma(struct vm_area_struct *vma)
 {
 	struct anon_vma *anon_vma = vma->anon_vma;
 	if (anon_vma)
 		down_write(&anon_vma->root->rwsem);
 }

 static inline void vma_unlock_anon_vma(struct vm_area_struct *vma)
 {
 	struct anon_vma *anon_vma = vma->anon_vma;
 	if (anon_vma)
 		up_write(&anon_vma->root->rwsem);
 }

 static inline void anon_vma_lock_write(struct anon_vma *anon_vma)
 {
 	down_write(&anon_vma->root->rwsem);
 }

 static inline void anon_vma_unlock_write(struct anon_vma *anon_vma)
 {
 	up_write(&anon_vma->root->rwsem);
 }

 static inline void anon_vma_lock_read(struct anon_vma *anon_vma)
 {
 	down_read(&anon_vma->root->rwsem);
 }

 static inline void anon_vma_unlock_read(struct anon_vma *anon_vma)
 {
 	up_read(&anon_vma->root->rwsem);
 }


 /*
  * anon_vma helper functions.
  */
 void anon_vma_init(void);	/* create anon_vma_cachep */
 int  anon_vma_prepare(struct vm_area_struct *);
 void unlink_anon_vmas(struct vm_area_struct *);
 int anon_vma_clone(struct vm_area_struct *, struct vm_area_struct *);
 int anon_vma_fork(struct vm_area_struct *, struct vm_area_struct *);

 static inline void anon_vma_merge(struct vm_area_struct *vma,
 				  struct vm_area_struct *next)
 {
 	VM_BUG_ON(vma->anon_vma != next->anon_vma);
 	unlink_anon_vmas(next);
 }

 struct anon_vma *page_get_anon_vma(struct page *page);

 /*
  * rmap interfaces called when adding or removing pte of page
  */
 void page_move_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
 void page_add_anon_rmap(struct page *, struct vm_area_struct *, unsigned long);
 void do_page_add_anon_rmap(struct page *, struct vm_area_struct *,
 			   unsigned long, int);
 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 *);

 void hugepage_add_anon_rmap(struct page *, struct vm_area_struct *,
 			    unsigned long);
 void hugepage_add_new_anon_rmap(struct page *, struct vm_area_struct *,
 				unsigned long);

 static inline void page_dup_rmap(struct page *page)
 {
 	atomic_inc(&page->_mapcount);
 }

 /*
  * Called from mm/vmscan.c to handle paging out
  */
 int page_referenced(struct page *, int is_locked,
 			struct mem_cgroup *memcg, unsigned long *vm_flags);

 #define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)

 int try_to_unmap(struct page *, enum ttu_flags flags);

 /*
  * 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 **, int);

 static inline pte_t *page_check_address(struct page *page, struct mm_struct *mm,
 					unsigned long address,
 					spinlock_t **ptlp, int sync)
 {
 	pte_t *ptep;

 	__cond_lock(*ptlp, ptep = __page_check_address(page, mm, address,
 						       ptlp, sync));
 	return ptep;
 }

 /*
  * 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 *);

 /*
  * called in munlock()/munmap() path to check for other vmas holding
  * the page mlocked.
  */
 int try_to_munlock(struct page *);

 /*
  * Called by memory-failure.c to kill processes.
  */
 struct anon_vma *page_lock_anon_vma_read(struct page *page);
 void page_unlock_anon_vma_read(struct anon_vma *anon_vma);
 int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);

 /*
  * rmap_walk_control: To control rmap traversing for specific needs
  *
  * arg: passed to rmap_one() and invalid_vma()
  * rmap_one: executed on each vma where page is mapped
  * done: for checking traversing termination condition
  * file_nonlinear: for handling file nonlinear mapping
  * anon_lock: for getting anon_lock by optimized way rather than default
  * invalid_vma: for skipping uninterested vma
  */
 struct rmap_walk_control {
 	void *arg;
 	int (*rmap_one)(struct page *page, struct vm_area_struct *vma,
 					unsigned long addr, void *arg);
 	int (*done)(struct page *page);
 	int (*file_nonlinear)(struct page *, struct address_space *, void *arg);
 	struct anon_vma *(*anon_lock)(struct page *page);
 	bool (*invalid_vma)(struct vm_area_struct *vma, void *arg);
 };

 int rmap_walk(struct page *page, struct rmap_walk_control *rwc);

 #else	/* !CONFIG_MMU */

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

 static inline int page_referenced(struct page *page, int is_locked,
 				  struct mem_cgroup *memcg,
 				  unsigned long *vm_flags)
 {
 	*vm_flags = 0;
 	return 0;
 }

 #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
 #define SWAP_MLOCK	3

 #endif	/* _LINUX_RMAP_H */
	#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/rwsem.h>
	#include <linux/memcontrol.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 {
	struct anon_vma root; / Root of this anon_vma tree */
	struct rw_semaphore rwsem; /* W: modification, R: walking the list */
	/*
	* The refcount is taken on an anon_vma when there is no
	* guarantee that the vma of page tables will exist for
	* the duration of the operation. A caller that takes
	* the reference is responsible for clearing up the
	* anon_vma if they are the last user on release
	*/
	atomic_t refcount;

	/*
	* NOTE: the LSB of the rb_root.rb_node is set by
	* mm_take_all_locks() _after_ taking the above lock. So the
	* rb_root must only be read/written after taking the above lock
	* to be sure to see a valid next pointer. The LSB bit itself
	* is serialized by a system wide lock only visible to
	* mm_take_all_locks() (mm_all_locks_mutex).
	*/
	struct rb_root rb_root; /* Interval tree of private "related" vmas */
	};

	/*
	* The copy-on-write semantics of fork mean that an anon_vma
	* can become associated with multiple processes. Furthermore,
	* each child process will have its own anon_vma, where new
	* pages for that process are instantiated.
	*
	* This structure allows us to find the anon_vmas associated
	* with a VMA, or the VMAs associated with an anon_vma.
	* The "same_vma" list contains the anon_vma_chains linking
	* all the anon_vmas associated with this VMA.
	* The "rb" field indexes on an interval tree the anon_vma_chains
	* which link all the VMAs associated with this anon_vma.
	*/
	struct anon_vma_chain {
	struct vm_area_struct *vma;
	struct anon_vma *anon_vma;
	struct list_head same_vma; /* locked by mmap_sem & page_table_lock */
	struct rb_node rb; /* locked by anon_vma->rwsem */
	unsigned long rb_subtree_last;
	#ifdef CONFIG_DEBUG_VM_RB
	unsigned long cached_vma_start, cached_vma_last;
	#endif
	};

	enum ttu_flags {
	TTU_UNMAP = 0, /* unmap mode */
	TTU_MIGRATION = 1, /* migration mode */
	TTU_MUNLOCK = 2, /* munlock mode */
	TTU_ACTION_MASK = 0xff,

	TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */
	TTU_IGNORE_ACCESS = (1 << 9), /* don't age */
	TTU_IGNORE_HWPOISON = (1 << 10),/* corrupted page is recoverable */
	};

	#ifdef CONFIG_MMU
	static inline void get_anon_vma(struct anon_vma *anon_vma)
	{
	atomic_inc(&anon_vma->refcount);
	}

	void __put_anon_vma(struct anon_vma *anon_vma);

	static inline void put_anon_vma(struct anon_vma *anon_vma)
	{
	if (atomic_dec_and_test(&anon_vma->refcount))
	__put_anon_vma(anon_vma);
	}

	static inline struct anon_vma page_anon_vma(struct page page)
	{
	if (((unsigned long)page->mapping & PAGE_MAPPING_FLAGS) !=
	PAGE_MAPPING_ANON)
	return NULL;
	return page_rmapping(page);
	}

	static inline void vma_lock_anon_vma(struct vm_area_struct *vma)
	{
	struct anon_vma *anon_vma = vma->anon_vma;
	if (anon_vma)
	down_write(&anon_vma->root->rwsem);
	}

	static inline void vma_unlock_anon_vma(struct vm_area_struct *vma)
	{
	struct anon_vma *anon_vma = vma->anon_vma;
	if (anon_vma)
	up_write(&anon_vma->root->rwsem);
	}

	static inline void anon_vma_lock_write(struct anon_vma *anon_vma)
	{
	down_write(&anon_vma->root->rwsem);
	}

	static inline void anon_vma_unlock_write(struct anon_vma *anon_vma)
	{
	up_write(&anon_vma->root->rwsem);
	}

	static inline void anon_vma_lock_read(struct anon_vma *anon_vma)
	{
	down_read(&anon_vma->root->rwsem);
	}

	static inline void anon_vma_unlock_read(struct anon_vma *anon_vma)
	{
	up_read(&anon_vma->root->rwsem);
	}


	/*
	* anon_vma helper functions.
	*/
	void anon_vma_init(void); /* create anon_vma_cachep */
	int anon_vma_prepare(struct vm_area_struct *);
	void unlink_anon_vmas(struct vm_area_struct *);
	int anon_vma_clone(struct vm_area_struct , struct vm_area_struct );
	int anon_vma_fork(struct vm_area_struct , struct vm_area_struct );

	static inline void anon_vma_merge(struct vm_area_struct *vma,
	struct vm_area_struct *next)
	{
	VM_BUG_ON(vma->anon_vma != next->anon_vma);
	unlink_anon_vmas(next);
	}

	struct anon_vma page_get_anon_vma(struct page page);

	/*
	* rmap interfaces called when adding or removing pte of page
	*/
	void page_move_anon_rmap(struct page , struct vm_area_struct , unsigned long);
	void page_add_anon_rmap(struct page , struct vm_area_struct , unsigned long);
	void do_page_add_anon_rmap(struct page , struct vm_area_struct ,
	unsigned long, int);
	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 *);

	void hugepage_add_anon_rmap(struct page , struct vm_area_struct ,
	unsigned long);
	void hugepage_add_new_anon_rmap(struct page , struct vm_area_struct ,
	unsigned long);

	static inline void page_dup_rmap(struct page *page)
	{
	atomic_inc(&page->_mapcount);
	}

	/*
	* Called from mm/vmscan.c to handle paging out
	*/
	int page_referenced(struct page *, int is_locked,
	struct mem_cgroup memcg, unsigned long vm_flags);

	#define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)

	int try_to_unmap(struct page *, enum ttu_flags flags);

	/*
	* 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 **, int);

	static inline pte_t page_check_address(struct page page, struct mm_struct *mm,
	unsigned long address,
	spinlock_t **ptlp, int sync)
	{
	pte_t *ptep;

	__cond_lock(*ptlp, ptep = __page_check_address(page, mm, address,
	ptlp, sync));
	return ptep;
	}

	/*
	* 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 *);

	/*
	* called in munlock()/munmap() path to check for other vmas holding
	* the page mlocked.
	*/
	int try_to_munlock(struct page *);

	/*
	* Called by memory-failure.c to kill processes.
	*/
	struct anon_vma page_lock_anon_vma_read(struct page page);
	void page_unlock_anon_vma_read(struct anon_vma *anon_vma);
	int page_mapped_in_vma(struct page page, struct vm_area_struct vma);

	/*
	* rmap_walk_control: To control rmap traversing for specific needs
	*
	* arg: passed to rmap_one() and invalid_vma()
	* rmap_one: executed on each vma where page is mapped
	* done: for checking traversing termination condition
	* file_nonlinear: for handling file nonlinear mapping
	* anon_lock: for getting anon_lock by optimized way rather than default
	* invalid_vma: for skipping uninterested vma
	*/
	struct rmap_walk_control {
	void *arg;
	int (rmap_one)(struct page page, struct vm_area_struct *vma,
	unsigned long addr, void *arg);
	int (done)(struct page page);
	int (file_nonlinear)(struct page , struct address_space , void arg);
	struct anon_vma (anon_lock)(struct page *page);
	bool (invalid_vma)(struct vm_area_struct vma, void *arg);
	};

	int rmap_walk(struct page page, struct rmap_walk_control rwc);

	#else /* !CONFIG_MMU */

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

	static inline int page_referenced(struct page *page, int is_locked,
	struct mem_cgroup *memcg,
	unsigned long *vm_flags)
	{
	*vm_flags = 0;
	return 0;
	}

	#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
	#define SWAP_MLOCK 3

	#endif /* _LINUX_RMAP_H */