x86: Fix error return sequence in __ioremap_caller()

kernel missed to free memtype if get_vm_area_caller failed in
__ioremap_caller.

This patch introduces error path to fix this and cleans up the
repetitive error return sequences that contributed to the
creation of the bug.

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
Acked-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
LKML-Reference: <1257389031-20429-1-git-send-email-dfeng@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/mm/ioremap.c

@@ -170,8 +170,7 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
 				(unsigned long long)phys_addr,
 				(unsigned long long)(phys_addr + size),
 				prot_val, new_prot_val);
-			free_memtype(phys_addr, phys_addr + size);
-			return NULL;
+			goto err_free_memtype;
 		}
 		prot_val = new_prot_val;
 	}
@@ -197,26 +196,25 @@ static void __iomem *__ioremap_caller(resource_size_t phys_addr,
 	 */
 	area = get_vm_area_caller(size, VM_IOREMAP, caller);
 	if (!area)
-		return NULL;
+		goto err_free_memtype;
 	area->phys_addr = phys_addr;
 	vaddr = (unsigned long) area->addr;
 
-	if (kernel_map_sync_memtype(phys_addr, size, prot_val)) {
-		free_memtype(phys_addr, phys_addr + size);
-		free_vm_area(area);
-		return NULL;
-	}
+	if (kernel_map_sync_memtype(phys_addr, size, prot_val))
+		goto err_free_area;
 
-	if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot)) {
-		free_memtype(phys_addr, phys_addr + size);
-		free_vm_area(area);
-		return NULL;
-	}
+	if (ioremap_page_range(vaddr, vaddr + size, phys_addr, prot))
+		goto err_free_area;
 
 	ret_addr = (void __iomem *) (vaddr + offset);
 	mmiotrace_ioremap(unaligned_phys_addr, unaligned_size, ret_addr);
 
 	return ret_addr;
+err_free_area:
+	free_vm_area(area);
+err_free_memtype:
+	free_memtype(phys_addr, phys_addr + size);
+	return NULL;
 }
 
 /**