diff --git a/mm/swapfile.c b/mm/swapfile.c
index aafcf3611b3102fdb635aae1a77e9a8cc8efdaf4..71b42ec55b783039b020cfeb3b410121b8a15fc0 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2088,7 +2088,6 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 
 	p->swap_file = swap_file;
 	mapping = swap_file->f_mapping;
-	inode = mapping->host;
 
 	for (i = 0; i < nr_swapfiles; i++) {
 		struct swap_info_struct *q = swap_info[i];
@@ -2101,6 +2100,8 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 		}
 	}
 
+	inode = mapping->host;
+	/* If S_ISREG(inode->i_mode) will do mutex_lock(&inode->i_mutex); */
 	error = claim_swapfile(p, inode);
 	if (unlikely(error))
 		goto bad_swap;
@@ -2187,8 +2188,10 @@ SYSCALL_DEFINE2(swapon, const char __user *, specialfile, int, swap_flags)
 	spin_unlock(&swap_lock);
 	vfree(swap_map);
 	if (swap_file) {
-		if (inode && S_ISREG(inode->i_mode))
+		if (inode && S_ISREG(inode->i_mode)) {
 			mutex_unlock(&inode->i_mutex);
+			inode = NULL;
+		}
 		filp_close(swap_file, NULL);
 	}
 out: