From 9fef3d2d15ae8ca24e4a145f2e189eea145d18c2 Mon Sep 17 00:00:00 2001 From: Milton Miller Date: Thu, 8 Jan 2009 02:14:18 +0000 Subject: [PATCH] hvc_console: Change an mb() to smp_mb() and add some comments I remember some history on this barrier. There was a race between open via /dev/console and the tty being fully setup. Its also why there is a temporary variable and the global is assigned at the end of the function. Signed-off-by: Milton Miller Signed-off-by: Benjamin Herrenschmidt --- drivers/char/hvc_console.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/drivers/char/hvc_console.c b/drivers/char/hvc_console.c index 5a8a4c28c867..f2685b747fb9 100644 --- a/drivers/char/hvc_console.c +++ b/drivers/char/hvc_console.c @@ -876,8 +876,11 @@ static int hvc_init(void) goto stop_thread; } - /* FIXME: This mb() seems completely random. Remove it. */ - mb(); + /* + * Make sure tty is fully registered before allowing it to be + * found by hvc_console_device. + */ + smp_mb(); hvc_driver = drv; return 0;