diff --git a/mm/swapfile.c b/mm/swapfile.c
index 61a604c12a96..4dade515b086 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1975,8 +1975,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	if (unlikely(error))
 		goto bad_swap;
 
-	swapfilepages = i_size_read(inode) >> PAGE_SHIFT;
-
 	/*
 	 * Read the swap header.
 	 */
@@ -2045,6 +2043,7 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	error = -EINVAL;
 	if (!maxpages)
 		goto bad_swap;
+	swapfilepages = i_size_read(inode) >> PAGE_SHIFT;
 	if (swapfilepages && maxpages > swapfilepages) {
 		printk(KERN_WARNING
 		       "Swap area shorter than signature indicates\n");