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

[Erwan LE RAY]

Hi Borut,

Please remove unused "flags" variable declaration.

Erwan.


On 6/4/19 3:55 PM, Erwan LE RAY wrote:
>
>> 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@xxxxxxx>
>>> CC: Maxime Coquelin <mcoquelin.stm32@xxxxxxxxx>, Alexandre Torgue
>>> <alexandre.torgue@xxxxxx>, Greg Kroah-Hartman
>>> <gregkh@xxxxxxxxxxxxxxxxxxx>, linux-kernel@xxxxxxxxxxxxxxx,
>>> borut.seljak@xxxxxxx, linux-serial@xxxxxxxxxxxxxxx, Jiri Slaby
>>> <jslaby@xxxxxxxx>, linux-stm32@xxxxxxxxxxxxxxxxxxxxxxxxxxxx,
>>> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
>>>
>>> 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@xxxxxxx>
>>> ---
>>>   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;
- 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;
>>>   }