Re: Fwd: [PATCH] serial: stm32: fix a recursive locking in stm32_config_rs485

[Erwan LE RAY <erwan.leray@st.com>]

Hi Borut,

Please add the following line in the commit message (before your 
sign-off) in a V2 of your patch:

fixes: 1bcda09d291081 ("serial: stm32: add support for RS485 hardware 
control mode")

I'm OK with the patch itself.

Erwan.


Subject: [PATCH] serial: stm32: fix a recursive locking in
> stm32_config_rs485
> Date: Tue,  4 Jun 2019 11:54:51 +0200
> From: Borut Seljak <borut.seljak@t-2.net>
> CC: Maxime Coquelin <mcoquelin.stm32@gmail.com>, Alexandre Torgue
> <alexandre.torgue@st.com>, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org>, linux-kernel@vger.kernel.org,
> borut.seljak@t-2.net, linux-serial@vger.kernel.org, Jiri Slaby
> <jslaby@suse.com>, linux-stm32@st-md-mailman.stormreply.com,
> linux-arm-kernel@lists.infradead.org
>
> Remove spin_lock_irqsave in stm32_config_rs485, it cause recursive locking.
> Already locked in uart_set_rs485_config.
>
> Signed-off-by: Borut Seljak <borut.seljak@t-2.net>
> ---
>   drivers/tty/serial/stm32-usart.c | 2 --
>   1 file changed, 2 deletions(-)
>
> diff --git a/drivers/tty/serial/stm32-usart.c
> b/drivers/tty/serial/stm32-usart.c
> index e8d7a7bb4339..da373a465f51 100644
> --- a/drivers/tty/serial/stm32-usart.c
> +++ b/drivers/tty/serial/stm32-usart.c
> @@ -107,7 +107,6 @@ static int stm32_config_rs485(struct uart_port *port,
>   	bool over8;
>   	unsigned long flags;
>   -	spin_lock_irqsave(&port->lock, flags);
>   	stm32_clr_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
>    	port->rs485 = *rs485conf;
> @@ -147,7 +146,6 @@ static int stm32_config_rs485(struct uart_port *port,
>   	}
>    	stm32_set_bits(port, ofs->cr1, BIT(cfg->uart_enable_bit));
> -	spin_unlock_irqrestore(&port->lock, flags);
>    	return 0;
>   }