Update Linux to v5.4.2

Change-Id: Idf6911045d9d382da2cfe01b1edff026404ac8fd
diff --git a/fs/d_path.c b/fs/d_path.c
index e8fce6b..0f1fc17 100644
--- a/fs/d_path.c
+++ b/fs/d_path.c
@@ -116,8 +116,10 @@
 				vfsmnt = &mnt->mnt;
 				continue;
 			}
-			if (!error)
-				error = is_mounted(vfsmnt) ? 1 : 2;
+			if (is_mounted(vfsmnt) && !is_anon_ns(mnt->mnt_ns))
+				error = 1;	// absolute root
+			else
+				error = 2;	// detached or not attached yet
 			break;
 		}
 		parent = dentry->d_parent;
@@ -316,7 +318,6 @@
 		end = ERR_PTR(-ENAMETOOLONG);
 	return end;
 }
-EXPORT_SYMBOL(simple_dname);
 
 /*
  * Write full pathname from the root of the filesystem into the buffer.