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Subject: Re: [PATCH 22/35] tty: make tty_operations::write_room return uint
To:     Jiri Slaby <jslaby@suse.cz>, gregkh@linuxfoundation.org
Cc:     linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org,
        Richard Henderson <rth@twiddle.net>,
        Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
        Matt Turner <mattst88@gmail.com>,
        Geert Uytterhoeven <geert@linux-m68k.org>,
        "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>,
        Helge Deller <deller@gmx.de>, Jeff Dike <jdike@addtoit.com>,
        Richard Weinberger <richard@nod.at>,
        Anton Ivanov <anton.ivanov@cambridgegreys.com>,
        Chris Zankel <chris@zankel.net>,
        Max Filippov <jcmvbkbc@gmail.com>,
        Arnd Bergmann <arnd@arndb.de>,
        Samuel Iglesias Gonsalvez <siglesias@igalia.com>,
        Jens Taprogge <jens.taprogge@taprogge.org>,
        Karsten Keil <isdn@linux-pingi.de>,
        Scott Branden <scott.branden@broadcom.com>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Heiko Carstens <hca@linux.ibm.com>,
        Vasily Gorbik <gor@linux.ibm.com>,
        Christian Borntraeger <borntraeger@de.ibm.com>,
        David Lin <dtwlin@gmail.com>, Johan Hovold <johan@kernel.org>,
        Alex Elder <elder@kernel.org>,
        Laurentiu Tudor <laurentiu.tudor@nxp.com>,
        Jiri Kosina <jikos@kernel.org>,
        David Sterba <dsterba@suse.com>,
        Shawn Guo <shawnguo@kernel.org>,
        Sascha Hauer <s.hauer@pengutronix.de>,
        Oliver Neukum <oneukum@suse.com>,
        Felipe Balbi <balbi@kernel.org>,
        Mathias Nyman <mathias.nyman@intel.com>,
        Marcel Holtmann <marcel@holtmann.org>,
        Johan Hedberg <johan.hedberg@gmail.com>,
        Luiz Augusto von Dentz <luiz.dentz@gmail.com>
References: <20210505091928.22010-1-jslaby@suse.cz>
 <20210505091928.22010-23-jslaby@suse.cz>
From:   Alex Elder <elder@ieee.org>
Message-ID: <608f186f-0c88-1a5d-e612-7f133476f1e3@ieee.org>
Date:   Wed, 5 May 2021 07:15:56 -0500
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On 5/5/21 4:19 AM, Jiri Slaby wrote:
> Line disciplines expect a positive value or zero returned from
> tty->ops->write_room (invoked by tty_write_room). So make this
> assumption explicit by using unsigned int as a return value. Both of
> tty->ops->write_room and tty_write_room.
> 
> Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> Cc: Richard Henderson <rth@twiddle.net>
> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
> Cc: Matt Turner <mattst88@gmail.com>
> Cc: Geert Uytterhoeven <geert@linux-m68k.org>
> Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
> Cc: Helge Deller <deller@gmx.de>
> Cc: Jeff Dike <jdike@addtoit.com>
> Cc: Richard Weinberger <richard@nod.at>
> Cc: Anton Ivanov <anton.ivanov@cambridgegreys.com>
> Cc: Chris Zankel <chris@zankel.net>
> Cc: Max Filippov <jcmvbkbc@gmail.com>
> Cc: Arnd Bergmann <arnd@arndb.de>
> Cc: Samuel Iglesias Gonsalvez <siglesias@igalia.com>
> Cc: Jens Taprogge <jens.taprogge@taprogge.org>
> Cc: Karsten Keil <isdn@linux-pingi.de>
> Cc: Scott Branden <scott.branden@broadcom.com>
> Cc: Ulf Hansson <ulf.hansson@linaro.org>
> Cc: "David S. Miller" <davem@davemloft.net>
> Cc: Jakub Kicinski <kuba@kernel.org>
> Cc: Heiko Carstens <hca@linux.ibm.com>
> Cc: Vasily Gorbik <gor@linux.ibm.com>
> Cc: Christian Borntraeger <borntraeger@de.ibm.com>
> Cc: David Lin <dtwlin@gmail.com>
> Cc: Johan Hovold <johan@kernel.org>
> Cc: Alex Elder <elder@kernel.org>
> Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> Cc: Jiri Kosina <jikos@kernel.org>
> Cc: David Sterba <dsterba@suse.com>
> Cc: Shawn Guo <shawnguo@kernel.org>
> Cc: Sascha Hauer <s.hauer@pengutronix.de>
> Cc: Oliver Neukum <oneukum@suse.com>
> Cc: Felipe Balbi <balbi@kernel.org>
> Cc: Mathias Nyman <mathias.nyman@intel.com>
> Cc: Marcel Holtmann <marcel@holtmann.org>
> Cc: Johan Hedberg <johan.hedberg@gmail.com>
> Cc: Luiz Augusto von Dentz <luiz.dentz@gmail.com>
> ---
>   arch/alpha/kernel/srmcons.c            | 2 +-
>   arch/m68k/emu/nfcon.c                  | 2 +-
>   arch/parisc/kernel/pdc_cons.c          | 2 +-
>   arch/um/drivers/line.c                 | 6 +++---
>   arch/um/drivers/line.h                 | 2 +-
>   arch/xtensa/platforms/iss/console.c    | 2 +-
>   drivers/char/pcmcia/synclink_cs.c      | 2 +-
>   drivers/char/ttyprintk.c               | 2 +-
>   drivers/ipack/devices/ipoctal.c        | 2 +-
>   drivers/isdn/capi/capi.c               | 6 +++---
>   drivers/misc/bcm-vk/bcm_vk_tty.c       | 2 +-
>   drivers/mmc/core/sdio_uart.c           | 2 +-
>   drivers/net/usb/hso.c                  | 4 ++--
>   drivers/s390/char/con3215.c            | 2 +-
>   drivers/s390/char/sclp_tty.c           | 4 ++--
>   drivers/s390/char/sclp_vt220.c         | 4 ++--
>   drivers/s390/char/tty3270.c            | 2 +-
>   drivers/staging/fwserial/fwserial.c    | 6 +++---
>   drivers/staging/gdm724x/gdm_tty.c      | 2 +-
>   drivers/staging/greybus/uart.c         | 2 +-
>   drivers/tty/amiserial.c                | 2 +-
>   drivers/tty/ehv_bytechan.c             | 4 ++--
>   drivers/tty/goldfish.c                 | 2 +-
>   drivers/tty/hvc/hvc_console.c          | 2 +-
>   drivers/tty/hvc/hvcs.c                 | 2 +-
>   drivers/tty/hvc/hvsi.c                 | 4 ++--
>   drivers/tty/ipwireless/tty.c           | 2 +-
>   drivers/tty/mips_ejtag_fdc.c           | 4 ++--
>   drivers/tty/moxa.c                     | 8 ++++----
>   drivers/tty/mxser.c                    | 2 +-
>   drivers/tty/n_gsm.c                    | 2 +-
>   drivers/tty/nozomi.c                   | 4 ++--
>   drivers/tty/pty.c                      | 2 +-
>   drivers/tty/serial/kgdb_nmi.c          | 2 +-
>   drivers/tty/serial/serial_core.c       | 4 ++--
>   drivers/tty/synclink_gt.c              | 6 +++---
>   drivers/tty/tty_ioctl.c                | 2 +-
>   drivers/tty/ttynull.c                  | 2 +-
>   drivers/tty/vcc.c                      | 4 ++--
>   drivers/tty/vt/vt.c                    | 2 +-
>   drivers/usb/class/cdc-acm.c            | 2 +-
>   drivers/usb/gadget/function/u_serial.c | 6 +++---
>   drivers/usb/host/xhci-dbgtty.c         | 4 ++--
>   drivers/usb/serial/usb-serial.c        | 2 +-
>   include/linux/tty.h                    | 2 +-
>   include/linux/tty_driver.h             | 4 ++--
>   net/bluetooth/rfcomm/tty.c             | 2 +-
>   47 files changed, 71 insertions(+), 71 deletions(-)

. . .

Looks good.

Acked-by: Alex Elder <elder@linaro.org.

> diff --git a/drivers/staging/greybus/uart.c b/drivers/staging/greybus/uart.c
> index b1e63f7798b0..529eccb99b6c 100644
> --- a/drivers/staging/greybus/uart.c
> +++ b/drivers/staging/greybus/uart.c
> @@ -440,7 +440,7 @@ static int gb_tty_write(struct tty_struct *tty, const unsigned char *buf,
>   	return count;
>   }
>   
> -static int gb_tty_write_room(struct tty_struct *tty)
> +static unsigned int gb_tty_write_room(struct tty_struct *tty)
>   {
>   	struct gb_tty *gb_tty = tty->driver_data;
>   	unsigned long flags;

. . .