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From: John Ogness <john.ogness@linutronix.de>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Peter Hurley <peter@hurleysoftware.com>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Cc: linux-serial@vger.kernel.org
Subject: [PATCH 2/3] serial: 8250: move rx_running out of the bitfield
Date: Fri, 31 Jul 2015 00:54:35 +0200
Message-ID: <87fv452r4k.fsf@linutronix.de>
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That bitfield is modified by read + or + write operation. If someone
sets any of the other two bits it might render the lock useless.

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
 drivers/tty/serial/8250/8250.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
index c43f74c..78f5e3a 100644
--- a/drivers/tty/serial/8250/8250.h
+++ b/drivers/tty/serial/8250/8250.h
@@ -44,7 +44,7 @@ struct uart_8250_dma {
 
 	unsigned char		tx_running:1;
 	unsigned char		tx_err: 1;
-	unsigned char		rx_running:1;
+	unsigned char		rx_running;
 };
 
 struct old_serial_port {
-- 
1.7.10.4

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Message-ID: <55BAB226.6090706@hurleysoftware.com>
Date: Thu, 30 Jul 2015 19:24:22 -0400
From: Peter Hurley <peter@hurleysoftware.com>
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To: John Ogness <john.ogness@linutronix.de>, linux-kernel@vger.kernel.org
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Tony Lindgren <tony@atomide.com>,
        Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
        linux-omap@vger.kernel.org, nsekhar@ti.com, nm@ti.com,
        linux-serial@vger.kernel.org
Subject: Re: [PATCH 2/3] serial: 8250: move rx_running out of the bitfield
References: <87fv452r4k.fsf@linutronix.de>
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On 07/30/2015 06:54 PM, John Ogness wrote:
> That bitfield is modified by read + or + write operation. If someone
> sets any of the other two bits it might render the lock useless.

Good catch.
Let's just make all of the fields not bitfield though.

Regards,
Peter Hurley

> Signed-off-by: John Ogness <john.ogness@linutronix.de>
> Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
> ---
>  drivers/tty/serial/8250/8250.h |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/tty/serial/8250/8250.h b/drivers/tty/serial/8250/8250.h
> index c43f74c..78f5e3a 100644
> --- a/drivers/tty/serial/8250/8250.h
> +++ b/drivers/tty/serial/8250/8250.h
> @@ -44,7 +44,7 @@ struct uart_8250_dma {
>  
>  	unsigned char		tx_running:1;
>  	unsigned char		tx_err: 1;
> -	unsigned char		rx_running:1;
> +	unsigned char		rx_running;
>  };
>  
>  struct old_serial_port {
> 


