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Date:   Thu, 23 Nov 2023 14:16:46 +0000
From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     Crescent CY Hsieh <crescentcy.hsieh@moxa.com>
Cc:     Jiri Slaby <jirislaby@kernel.org>, linux-kernel@vger.kernel.org,
        linux-serial@vger.kernel.org
Subject: Re: [PATCH v5] tty: serial: Add RS422 flag to struct serial_rs485
Message-ID: <2023112346-immunity-clamshell-51c7@gregkh>
References: <20231121095122.15948-1-crescentcy.hsieh@moxa.com>
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In-Reply-To: <20231121095122.15948-1-crescentcy.hsieh@moxa.com>
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On Tue, Nov 21, 2023 at 05:51:22PM +0800, Crescent CY Hsieh wrote:
> --- a/include/uapi/linux/serial.h
> +++ b/include/uapi/linux/serial.h
> @@ -11,6 +11,7 @@
>  #ifndef _UAPI_LINUX_SERIAL_H
>  #define _UAPI_LINUX_SERIAL_H
>  
> +#include <linux/const.h>
>  #include <linux/types.h>
>  
>  #include <linux/tty_flags.h>
> @@ -137,17 +138,19 @@ struct serial_icounter_struct {
>   * * %SER_RS485_ADDRB		- Enable RS485 addressing mode.
>   * * %SER_RS485_ADDR_RECV - Receive address filter (enables @addr_recv). Requires %SER_RS485_ADDRB.
>   * * %SER_RS485_ADDR_DEST - Destination address (enables @addr_dest). Requires %SER_RS485_ADDRB.
> + * * %SER_RS485_MODE_RS422	- Enable RS422. Requires %SER_RS485_ENABLED.
>   */
>  struct serial_rs485 {
>  	__u32	flags;
> -#define SER_RS485_ENABLED		(1 << 0)
> -#define SER_RS485_RTS_ON_SEND		(1 << 1)
> -#define SER_RS485_RTS_AFTER_SEND	(1 << 2)
> -#define SER_RS485_RX_DURING_TX		(1 << 4)
> -#define SER_RS485_TERMINATE_BUS		(1 << 5)
> -#define SER_RS485_ADDRB			(1 << 6)
> -#define SER_RS485_ADDR_RECV		(1 << 7)
> -#define SER_RS485_ADDR_DEST		(1 << 8)
> +#define SER_RS485_ENABLED		_BITUL(0)
> +#define SER_RS485_RTS_ON_SEND		_BITUL(1)
> +#define SER_RS485_RTS_AFTER_SEND	_BITUL(2)
> +#define SER_RS485_RX_DURING_TX		_BITUL(3)
> +#define SER_RS485_TERMINATE_BUS		_BITUL(4)
> +#define SER_RS485_ADDRB			_BITUL(5)
> +#define SER_RS485_ADDR_RECV		_BITUL(6)
> +#define SER_RS485_ADDR_DEST		_BITUL(7)
> +#define SER_RS485_MODE_RS422		_BITUL(8)

You just broke userspace by changing the flags for existing values :(

Please be much more careful in the future, do not do "cleanup" patches
along with a "add a new feature" patch, as it would have been much more
obvious as to what happened here if you had done that.

thanks,

greg k-h