diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index e89d24815f26760370a17616e7f0ed4e1d57cfd2..4cf30dee816154fcda7229b6967a28d644bbb746 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -555,10 +555,12 @@ static int __change_page_attr(struct cpa_data *cpa, int primary)
 	if (!pte_val(old_pte)) {
 		if (!primary)
 			return 0;
-		WARN(1, KERN_WARNING "CPA: called for zero pte. "
-		       "vaddr = %lx cpa->vaddr = %lx\n", address,
-		       *cpa->vaddr);
-		return -EINVAL;
+
+		/*
+		 *  Special error value returned, indicating that the mapping
+		 * did not exist at this address.
+		 */
+		return -EFAULT;
 	}
 
 	if (level == PG_LEVEL_4K) {
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c
index 8b08fb955274148454a2acaa538c78215322e655..160c42d3eb8f0a5393140b43ebb496cf8fe200d1 100644
--- a/arch/x86/mm/pat.c
+++ b/arch/x86/mm/pat.c
@@ -505,6 +505,35 @@ static inline int range_is_allowed(unsigned long pfn, unsigned long size)
 }
 #endif /* CONFIG_STRICT_DEVMEM */
 
+/*
+ * Change the memory type for the physial address range in kernel identity
+ * mapping space if that range is a part of identity map.
+ */
+static int kernel_map_sync_memtype(u64 base, unsigned long size,
+					unsigned long flags)
+{
+	unsigned long id_sz;
+	int ret;
+
+	if (!pat_enabled || base >= __pa(high_memory))
+		return 0;
+
+	id_sz = (__pa(high_memory) < base + size) ?
+						__pa(high_memory) - base :
+						size;
+
+	ret = ioremap_change_attr((unsigned long)__va(base), id_sz, flags);
+	/*
+	 * -EFAULT return means that the addr was not valid and did not have
+	 * any identity mapping. That case is a success for
+	 * kernel_map_sync_memtype.
+	 */
+	if (ret == -EFAULT)
+		ret = 0;
+
+	return ret;
+}
+
 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
 				unsigned long size, pgprot_t *vma_prot)
 {
@@ -555,9 +584,7 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
 	if (retval < 0)
 		return 0;
 
-	if (((pfn < max_low_pfn_mapped) ||
-	     (pfn >= (1UL<<(32 - PAGE_SHIFT)) && pfn < max_pfn_mapped)) &&
-	    ioremap_change_attr((unsigned long)__va(offset), size, flags) < 0) {
+	if (kernel_map_sync_memtype(offset, size, flags)) {
 		free_memtype(offset, offset + size);
 		printk(KERN_INFO
 		"%s:%d /dev/mem ioremap_change_attr failed %s for %Lx-%Lx\n",
@@ -605,7 +632,7 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
 				int strict_prot)
 {
 	int is_ram = 0;
-	int id_sz, ret;
+	int ret;
 	unsigned long flags;
 	unsigned long want_flags = (pgprot_val(*vma_prot) & _PAGE_CACHE_MASK);
 
@@ -646,15 +673,7 @@ static int reserve_pfn_range(u64 paddr, unsigned long size, pgprot_t *vma_prot,
 				     flags);
 	}
 
-	/* Need to keep identity mapping in sync */
-	if (paddr >= __pa(high_memory))
-		return 0;
-
-	id_sz = (__pa(high_memory) < paddr + size) ?
-				__pa(high_memory) - paddr :
-				size;
-
-	if (ioremap_change_attr((unsigned long)__va(paddr), id_sz, flags) < 0) {
+	if (kernel_map_sync_memtype(paddr, size, flags)) {
 		free_memtype(paddr, paddr + size);
 		printk(KERN_ERR
 			"%s:%d reserve_pfn_range ioremap_change_attr failed %s "