1 files changed, 205 insertions, 0 deletions
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
new file mode 100644
index 00000000000..b019ae64e2a
--- /dev/null
+++ b/include/linux/rmap.h
@@ -0,0 +1,205 @@
+#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 */
+#ifdef CONFIG_KSM
+	atomic_t ksm_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;	/* List of private "related" vmas */
+};
+
+#ifdef CONFIG_MMU
+#ifdef CONFIG_KSM
+static inline void ksm_refcount_init(struct anon_vma *anon_vma)
+{
+	atomic_set(&anon_vma->ksm_refcount, 0);
+}
+
+static inline int ksm_refcount(struct anon_vma *anon_vma)
+{
+	return atomic_read(&anon_vma->ksm_refcount);
+}
+#else
+static inline void ksm_refcount_init(struct anon_vma *anon_vma)
+{
+}
+
+static inline int ksm_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 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 *);
+void anon_vma_free(struct anon_vma *);
+
+/*
+ * 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 *);
+
+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 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
+#define SWAP_MLOCK	3
+
+#endif	/* _LINUX_RMAP_H */