diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 3d68ef6d..de36c88 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -704,21 +704,18 @@
 int track_pfn_vma_new(struct vm_area_struct *vma, pgprot_t *prot,
 			unsigned long pfn, unsigned long size)
 {
+	resource_size_t paddr = (resource_size_t)pfn << PAGE_SHIFT;
 	unsigned long flags;
-	resource_size_t paddr;
-	unsigned long vma_size = vma->vm_end - vma->vm_start;
 
-	if (is_linear_pfn_mapping(vma)) {
-		/* reserve the whole chunk starting from vm_pgoff */
-		paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
-		return reserve_pfn_range(paddr, vma_size, prot, 0);
-	}
+	/* reserve the whole chunk starting from paddr */
+	if (is_linear_pfn_mapping(vma))
+		return reserve_pfn_range(paddr, size, prot, 0);
 
 	if (!pat_enabled)
 		return 0;
 
 	/* for vm_insert_pfn and friends, we set prot based on lookup */
-	flags = lookup_memtype(pfn << PAGE_SHIFT);
+	flags = lookup_memtype(paddr);
 	*prot = __pgprot((pgprot_val(vma->vm_page_prot) & (~_PAGE_CACHE_MASK)) |
 			 flags);
 
@@ -728,20 +725,28 @@
 /*
  * untrack_pfn_vma is called while unmapping a pfnmap for a region.
  * untrack can be called for a specific region indicated by pfn and size or
- * can be for the entire vma (in which case size can be zero).
+ * can be for the entire vma (in which case pfn, size are zero).
  */
 void untrack_pfn_vma(struct vm_area_struct *vma, unsigned long pfn,
 			unsigned long size)
 {
 	resource_size_t paddr;
-	unsigned long vma_size = vma->vm_end - vma->vm_start;
+	unsigned long prot;
 
-	if (is_linear_pfn_mapping(vma)) {
-		/* free the whole chunk starting from vm_pgoff */
-		paddr = (resource_size_t)vma->vm_pgoff << PAGE_SHIFT;
-		free_pfn_range(paddr, vma_size);
+	if (!is_linear_pfn_mapping(vma))
 		return;
+
+	/* free the chunk starting from pfn or the whole chunk */
+	paddr = (resource_size_t)pfn << PAGE_SHIFT;
+	if (!paddr && !size) {
+		if (follow_phys(vma, vma->vm_start, 0, &prot, &paddr)) {
+			WARN_ON_ONCE(1);
+			return;
+		}
+
+		size = vma->vm_end - vma->vm_start;
 	}
+	free_pfn_range(paddr, size);
 }
 
 pgprot_t pgprot_writecombine(pgprot_t prot)