Support for remap_page_range in objrmap

@@ -107,6 +107,7 @@
 #define VM_RESERVED	0x00080000	/* Don't unmap it from swap_out */
 #define VM_ACCOUNT	0x00100000	/* Is a VM accounted object */
 #define VM_HUGETLB	0x00400000	/* Huge TLB Page VM */
+#define VM_NONLINEAR	0x00800000	/* Nonlinear area */
 
 #ifdef CONFIG_STACK_GROWSUP
 #define VM_STACK_FLAGS	(VM_GROWSUP | VM_DATA_DEFAULT_FLAGS | VM_ACCOUNT)

@@ -20,6 +20,7 @@
 #define MAP_NORESERVE	0x4000		/* don't check for reservations */
 #define MAP_POPULATE	0x8000		/* populate (prefault) pagetables */
 #define MAP_NONBLOCK	0x10000		/* do not block on IO */
+#define MAP_NONLINEAR	0x20000		/* will be used for remap_file_pages */
 
 #define MS_ASYNC	1		/* sync memory asynchronously */
 #define MS_INVALIDATE	2		/* invalidate the caches */

@@ -78,6 +78,8 @@
 	if (prot & PROT_WRITE)
 		entry = pte_mkwrite(pte_mkdirty(entry));
 	set_pte(pte, entry);
+	if (vma->vm_flags & VM_NONLINEAR)
+		SetPageAnon(page);
 	pte_chain = page_add_rmap(page, pte, pte_chain);
 	pte_unmap(pte);
 	flush_tlb_page(vma, addr);

@@ -133,7 +135,8 @@
 	 * and that the remapped range is valid and fully within
 	 * the single existing vma:
 	 */
-	if (vma && (vma->vm_flags & VM_SHARED) &&
+	if (vma &&
+	    ((vma->vm_flags & (VM_SHARED|VM_NONLINEAR)) == (VM_SHARED|VM_NONLINEAR)) &&
 		vma->vm_ops && vma->vm_ops->populate &&
 			end > start && start >= vma->vm_start &&
 				end <= vma->vm_end) {

@@ -219,6 +219,7 @@
 	flag_bits =
 		_trans(flags, MAP_GROWSDOWN, VM_GROWSDOWN) |
 		_trans(flags, MAP_DENYWRITE, VM_DENYWRITE) |
+		_trans(flags, MAP_NONLINEAR, VM_NONLINEAR) |
 		_trans(flags, MAP_EXECUTABLE, VM_EXECUTABLE);
 	return prot_bits | flag_bits;
 #undef _trans

@@ -111,20 +111,20 @@
 		goto out;
 	}
 	pgd = pgd_offset(mm, address);
-	if (!pgd_present(*pgd)) {
+	if (!pgd_present(*pgd))
 		goto out_unlock;
-	}
+
 	pmd = pmd_offset(pgd, address);
-	if (!pmd_present(*pmd)) {
+	if (!pmd_present(*pmd))
 		goto out_unlock;
-	}
+
 	pte = pte_offset_map(pmd, address);
-	if (!pte_present(*pte)) {
+	if (!pte_present(*pte))
 		goto out_unmap;
-	}
-	if (page_to_pfn(page) != pte_pfn(*pte)) {
+
+	if (page_to_pfn(page) != pte_pfn(*pte))
 		goto out_unmap;
-	}
+
 	if (ptep_test_and_clear_young(pte))
 		referenced++;
 out_unmap:

@@ -156,13 +156,11 @@
 	if (down_trylock(&mapping->i_shared_sem))
 		return 1;
 
-	list_for_each_entry(vma, &mapping->i_mmap, shared) {
+	list_for_each_entry(vma, &mapping->i_mmap, shared)
 		referenced += page_referenced_obj_one(vma, page);
-	}
 
-	list_for_each_entry(vma, &mapping->i_mmap_shared, shared) {
+	list_for_each_entry(vma, &mapping->i_mmap_shared, shared)
 		referenced += page_referenced_obj_one(vma, page);
-	}
 
 	up(&mapping->i_shared_sem);
 

@@ -444,20 +442,19 @@
 		goto out;
 	}
 	pgd = pgd_offset(mm, address);
-	if (!pgd_present(*pgd)) {
+	if (!pgd_present(*pgd))
 		goto out_unlock;
-	}
+
 	pmd = pmd_offset(pgd, address);
-	if (!pmd_present(*pmd)) {
+	if (!pmd_present(*pmd))
 		goto out_unlock;
-	}
+
 	pte = pte_offset_map(pmd, address);
-	if (!pte_present(*pte)) {
+	if (!pte_present(*pte))
 		goto out_unmap;
-	}
-	if (page_to_pfn(page) != pte_pfn(*pte)) {
+
+	if (page_to_pfn(page) != pte_pfn(*pte))
 		goto out_unmap;
-	}
 
 	if (vma->vm_flags & VM_LOCKED) {
 		ret =  SWAP_FAIL;