VM: add common helper function to create the page tables

This logic was duplicated four times, for no good reason. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
git-mirror · Nov 29, 2005 · c9cfcdd · c9cfcdd
1 parent 4168f7a
commit c9cfcdd
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Showing 4 changed files with 19 additions and 45 deletions.
diff --git a/fs/exec.c b/fs/exec.c
@@ -306,24 +306,14 @@ void install_arg_page(struct vm_area_struct *vma,
 			struct page *page, unsigned long address)
 {
 	struct mm_struct *mm = vma->vm_mm;
-	pgd_t * pgd;
-	pud_t * pud;
-	pmd_t * pmd;
 	pte_t * pte;
 	spinlock_t *ptl;
 
 	if (unlikely(anon_vma_prepare(vma)))
 		goto out;
 
 	flush_dcache_page(page);
-	pgd = pgd_offset(mm, address);
-	pud = pud_alloc(mm, pgd, address);
-	if (!pud)
-		goto out;
-	pmd = pmd_alloc(mm, pud, address);
-	if (!pmd)
-		goto out;
-	pte = pte_alloc_map_lock(mm, pmd, address, &ptl);
+	pte = get_locked_pte(mm, address, &ptl);
 	if (!pte)
 		goto out;
 	if (!pte_none(*pte)) {

diff --git a/include/linux/mm.h b/include/linux/mm.h
@@ -742,6 +742,8 @@ struct shrinker;
 extern struct shrinker *set_shrinker(int, shrinker_t);
 extern void remove_shrinker(struct shrinker *shrinker);
 
+extern pte_t *FASTCALL(get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl));
+
 int __pud_alloc(struct mm_struct *mm, pgd_t *pgd, unsigned long address);
 int __pmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long address);
 int __pte_alloc(struct mm_struct *mm, pmd_t *pmd, unsigned long address);

diff --git a/mm/fremap.c b/mm/fremap.c
@@ -55,20 +55,10 @@ int install_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	pgoff_t size;
 	int err = -ENOMEM;
 	pte_t *pte;
-	pmd_t *pmd;
-	pud_t *pud;
-	pgd_t *pgd;
 	pte_t pte_val;
 	spinlock_t *ptl;
 
-	pgd = pgd_offset(mm, addr);
-	pud = pud_alloc(mm, pgd, addr);
-	if (!pud)
-		goto out;
-	pmd = pmd_alloc(mm, pud, addr);
-	if (!pmd)
-		goto out;
-	pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
+	pte = get_locked_pte(mm, addr, &ptl);
 	if (!pte)
 		goto out;
 
@@ -110,20 +100,10 @@ int install_file_pte(struct mm_struct *mm, struct vm_area_struct *vma,
 {
 	int err = -ENOMEM;
 	pte_t *pte;
-	pmd_t *pmd;
-	pud_t *pud;
-	pgd_t *pgd;
 	pte_t pte_val;
 	spinlock_t *ptl;
 
-	pgd = pgd_offset(mm, addr);
-	pud = pud_alloc(mm, pgd, addr);
-	if (!pud)
-		goto out;
-	pmd = pmd_alloc(mm, pud, addr);
-	if (!pmd)
-		goto out;
-	pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
+	pte = get_locked_pte(mm, addr, &ptl);
 	if (!pte)
 		goto out;
 

diff --git a/mm/memory.c b/mm/memory.c
@@ -1146,6 +1146,18 @@ int zeromap_page_range(struct vm_area_struct *vma,
 	return err;
 }
 
+pte_t *get_locked_pte(struct mm_struct *mm, unsigned long addr, spinlock_t **ptl)
+{
+	pgd_t * pgd = pgd_offset(mm, addr);
+	pud_t * pud = pud_alloc(mm, pgd, addr);
+	if (pud) {
+		pmd_t * pmd = pmd_alloc(mm, pgd, addr);
+		if (pmd)
+			return pte_alloc_map_lock(mm, pmd, addr, ptl);
+	}
+	return NULL;
+}
+
 /*
  * This is the old fallback for page remapping.
  *
@@ -1156,25 +1168,15 @@ int zeromap_page_range(struct vm_area_struct *vma,
 static int insert_page(struct mm_struct *mm, unsigned long addr, struct page *page, pgprot_t prot)
 {
 	int retval;
-	pgd_t * pgd;
-	pud_t * pud;
-	pmd_t * pmd;  
-	pte_t * pte;
+	pte_t *pte;
 	spinlock_t *ptl;  
 
 	retval = -EINVAL;
 	if (PageAnon(page) || !PageReserved(page))
 		goto out;
 	retval = -ENOMEM;
 	flush_dcache_page(page);
-	pgd = pgd_offset(mm, addr);
-	pud = pud_alloc(mm, pgd, addr);
-	if (!pud)
-		goto out;
-	pmd = pmd_alloc(mm, pud, addr);
-	if (!pmd)
-		goto out;
-	pte = pte_alloc_map_lock(mm, pmd, addr, &ptl);
+	pte = get_locked_pte(mm, addr, &ptl);
 	if (!pte)
 		goto out;
 	retval = -EBUSY;