[PATCH v2 2.6.38-rc8-tip 1/20] 1: mm: Move replace_page() to mm/memory.c

[Srikar Dronamraju <srikar@linux.vnet.ibm.com>]

User bkpt will use background page replacement approach to insert/delete
breakpoints. Background page replacement approach is based on
replace_page. Hence replace_page() loses its static attribute.

Signed-off-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
---
 include/linux/mm.h |    2 ++
 mm/ksm.c           |   62 ----------------------------------------------------
 mm/memory.c        |   62 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 64 insertions(+), 62 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 679300c..01a0740 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -984,6 +984,8 @@ void account_page_writeback(struct page *page);
 int set_page_dirty(struct page *page);
 int set_page_dirty_lock(struct page *page);
 int clear_page_dirty_for_io(struct page *page);
+int replace_page(struct vm_area_struct *vma, struct page *page,
+					struct page *kpage, pte_t orig_pte);
 
 /* Is the vma a continuation of the stack vma above it? */
 static inline int vma_stack_continue(struct vm_area_struct *vma, unsigned long addr)
diff --git a/mm/ksm.c b/mm/ksm.c
index c2b2a94..f46e20d 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -765,68 +765,6 @@ out:
 	return err;
 }
 
-/**
- * replace_page - replace page in vma by new ksm page
- * @vma:      vma that holds the pte pointing to page
- * @page:     the page we are replacing by kpage
- * @kpage:    the ksm page we replace page by
- * @orig_pte: the original value of the pte
- *
- * Returns 0 on success, -EFAULT on failure.
- */
-static int replace_page(struct vm_area_struct *vma, struct page *page,
-			struct page *kpage, pte_t orig_pte)
-{
-	struct mm_struct *mm = vma->vm_mm;
-	pgd_t *pgd;
-	pud_t *pud;
-	pmd_t *pmd;
-	pte_t *ptep;
-	spinlock_t *ptl;
-	unsigned long addr;
-	int err = -EFAULT;
-
-	addr = page_address_in_vma(page, vma);
-	if (addr == -EFAULT)
-		goto out;
-
-	pgd = pgd_offset(mm, addr);
-	if (!pgd_present(*pgd))
-		goto out;
-
-	pud = pud_offset(pgd, addr);
-	if (!pud_present(*pud))
-		goto out;
-
-	pmd = pmd_offset(pud, addr);
-	BUG_ON(pmd_trans_huge(*pmd));
-	if (!pmd_present(*pmd))
-		goto out;
-
-	ptep = pte_offset_map_lock(mm, pmd, addr, &ptl);
-	if (!pte_same(*ptep, orig_pte)) {
-		pte_unmap_unlock(ptep, ptl);
-		goto out;
-	}
-
-	get_page(kpage);
-	page_add_anon_rmap(kpage, vma, addr);
-
-	flush_cache_page(vma, addr, pte_pfn(*ptep));
-	ptep_clear_flush(vma, addr, ptep);
-	set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot));
-
-	page_remove_rmap(page);
-	if (!page_mapped(page))
-		try_to_free_swap(page);
-	put_page(page);
-
-	pte_unmap_unlock(ptep, ptl);
-	err = 0;
-out:
-	return err;
-}
-
 static int page_trans_compound_anon_split(struct page *page)
 {
 	int ret = 0;
diff --git a/mm/memory.c b/mm/memory.c
index 5823698..2a3021c 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2669,6 +2669,68 @@ void unmap_mapping_range(struct address_space *mapping,
 }
 EXPORT_SYMBOL(unmap_mapping_range);
 
+/**
+ * replace_page - replace page in vma by new ksm page
+ * @vma:      vma that holds the pte pointing to page
+ * @page:     the page we are replacing by kpage
+ * @kpage:    the ksm page we replace page by
+ * @orig_pte: the original value of the pte
+ *
+ * Returns 0 on success, -EFAULT on failure.
+ */
+int replace_page(struct vm_area_struct *vma, struct page *page,
+			struct page *kpage, pte_t orig_pte)
+{
+	struct mm_struct *mm = vma->vm_mm;
+	pgd_t *pgd;
+	pud_t *pud;
+	pmd_t *pmd;
+	pte_t *ptep;
+	spinlock_t *ptl;
+	unsigned long addr;
+	int err = -EFAULT;
+
+	addr = page_address_in_vma(page, vma);
+	if (addr == -EFAULT)
+		goto out;
+
+	pgd = pgd_offset(mm, addr);
+	if (!pgd_present(*pgd))
+		goto out;
+
+	pud = pud_offset(pgd, addr);
+	if (!pud_present(*pud))
+		goto out;
+
+	pmd = pmd_offset(pud, addr);
+	BUG_ON(pmd_trans_huge(*pmd));
+	if (!pmd_present(*pmd))
+		goto out;
+
+	ptep = pte_offset_map_lock(mm, pmd, addr, &ptl);
+	if (!pte_same(*ptep, orig_pte)) {
+		pte_unmap_unlock(ptep, ptl);
+		goto out;
+	}
+
+	get_page(kpage);
+	page_add_anon_rmap(kpage, vma, addr);
+
+	flush_cache_page(vma, addr, pte_pfn(*ptep));
+	ptep_clear_flush(vma, addr, ptep);
+	set_pte_at_notify(mm, addr, ptep, mk_pte(kpage, vma->vm_page_prot));
+
+	page_remove_rmap(page);
+	if (!page_mapped(page))
+		try_to_free_swap(page);
+	put_page(page);
+
+	pte_unmap_unlock(ptep, ptl);
+	err = 0;
+out:
+	return err;
+}
+
 int vmtruncate_range(struct inode *inode, loff_t offset, loff_t end)
 {
 	struct address_space *mapping = inode->i_mapping;

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