New helper - current_umask()

current->fs->umask is what most of fs_struct users are doing.
Put that into a helper function.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index a8ddadb..9167853 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -602,7 +602,7 @@
 		dentry->d_fsdata = attr;
 	}
 
-	mode &= ~current->fs->umask;
+	mode &= ~current_umask();
 	ret = mnt_want_write(mqueue_mnt);
 	if (ret)
 		goto out;