[PATCH] uml: locking documentation

Some locking documentation and a cleanup.  uml_exitcode is copied into a local
before sprintf sees it, in case sprintf does anything non-atomic with it.

The rest are comments about why certain globals don't need any kind of
locking.

Signed-off-by: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/um/drivers/stdio_console.c b/arch/um/drivers/stdio_console.c
index 5e44adb..e4bfcfe 100644
--- a/arch/um/drivers/stdio_console.c
+++ b/arch/um/drivers/stdio_console.c
@@ -108,6 +108,7 @@
 	return line_open(vts, tty);
 }
 
+/* Set in an initcall, checked in an exitcall */
 static int con_init_done = 0;
 
 static const struct tty_operations console_ops = {