#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>
#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 {
spinlock_t lock; /* Serialize access to vma list */
#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
/*
* The external_refcount is taken by either KSM or page migration
* to take a reference to 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 external_refcount;
#endif
/*
* NOTE: the LSB of the head.next is set by
* mm_take_all_locks() _after_ taking the above lock. So the
* head 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 list_head head; /* Chain 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 "same_anon_vma" list contains 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 list_head same_anon_vma; /* locked by anon_vma->lock */
};
#ifdef CONFIG_MMU
#if defined(CONFIG_KSM) || defined(CONFIG_MIGRATION)
static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma)
{
atomic_set(&anon_vma->external_refcount, 0);
}
static inline int anonvma_external_refcount(struct anon_vma *anon_vma)
{
return atomic_read(&anon_vma->external_refcount);
}
#else
static inline void anonvma_external_refcount_init(struct anon_vma *anon_vma)
{
}
static inline int anonvma_external_refcount(struct anon_vma *anon_vma)
{
return 0;
}
#endif /* CONFIG_KSM */
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)
spin_lock(&anon_vma->lock);
}
static inline void vma_unlock_anon_vma(struct vm_area_struct *vma)
{
struct anon_vma *anon_vma = vma->anon_vma;
if (anon_vma)
spin_unlock(&anon_vma->lock);
}
static inline void anon_vma_lock(struct anon_vma *anon_vma)
{
spin_lock(&anon_vma->lock);
}
static inline void anon_vma_unlock(struct anon_vma *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 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 *);
void __anon_vma_link(struct vm_area_struct *);
void anon_vma_free(struct anon_vma *);
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);
}
/*
* 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 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 *);
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 *cnt, unsigned long *vm_flags);
int page_referenced_one(struct page *, struct vm_area_struct *,
unsigned long address, unsigned int *mapcount, unsigned long *vm_flags);
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 */
};
#define TTU_ACTION(x) ((x) & TTU_ACTION_MASK)
int try_to_unmap(struct page *, enum ttu_flags flags);
int try_to_unmap_one(struct page *, struct vm_area_struct *,
unsigned long address, 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);
/*
* 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(struct page *page);
void page_unlock_anon_vma(struct anon_vma *anon_vma);
int page_mapped_in_vma(struct page *page, struct vm_area_struct *vma);
/*
* Called by migrate.c to remove migration ptes, but might be used more later.
*/
int rmap_walk(struct page *page, int (*rmap_one)(struct page *,
struct vm_area_struct *, unsigned long, void *), void *arg);
#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 *cnt,
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 */
