linux-kernel - Re: [PATCH] atmel_serial: RS485: receiving enabled when sending data

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20110823093035.GB19622@n2100.arm.linux.org.uk>
Date:	Tue, 23 Aug 2011 10:30:35 +0100
From:	Russell King - ARM Linux <linux@....linux.org.uk>
To:	Claudio Scordino <claudio@...dence.eu.com>
Cc:	Greg KH <greg@...ah.com>, linux-arm-kernel@...ts.infradead.org,
	nicolas.ferre@...el.com, linux-kernel@...r.kernel.org,
	linux-serial@...r.kernel.org, Bernhard Roth <br@...net.de>
Subject: Re: [PATCH] atmel_serial: RS485: receiving enabled when sending
	data

On Tue, Aug 23, 2011 at 10:30:46AM +0200, Claudio Scordino wrote:
> diff --git a/drivers/tty/serial/atmel_serial.c b/drivers/tty/serial/atmel_serial.c
> index af9b781..5f6c745 100644
> --- a/drivers/tty/serial/atmel_serial.c
> +++ b/drivers/tty/serial/atmel_serial.c
> @@ -339,8 +339,9 @@ static void atmel_stop_tx(struct uart_port *port)
>  	/* Disable interrupts */
>  	UART_PUT_IDR(port, atmel_port->tx_done_mask);
>  
> -	if (atmel_port->rs485.flags & SER_RS485_ENABLED)
> -		atmel_start_rx(port);
> +	if ((atmel_port->rs485.flags & SER_RS485_ENABLED) &&
> +		!(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX))
> +			atmel_start_rx(port);

However, this is incorrect formatting.  The code following the 'if' ends
up being indented by two tabs.

This illustrates why the whole idea that tabs should only be used for
indenting is wrong.  You end up with either what you have above, or:

	if ((atmel_port->rs485.flags & SER_RS485_ENABLED) &&
		!(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX))
		atmel_start_rx(port);

both of which are dire for readability.  The only sane way to do this is
to ignore that stupid "indentation by tabs only" thing and do it as the
kernel code has _always_ been done over the last 19 years:

	if ((atmel_port->rs485.flags & SER_RS485_ENABLED) &&
	    !(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX))
		atmel_start_rx(port);

IOW, use spaces to align the wrapped 'if' statement.

> +		if ((atmel_port->rs485.flags & SER_RS485_ENABLED) &&
> +			!(atmel_port->rs485.flags & SER_RS485_RX_DURING_TX)) {
> +				/* DMA done, stop TX, start RX for RS485 */
> +				atmel_start_rx(port);

And here it makes it look like there's a missing brace.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/