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03b3b1a240
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> Acked-by: Laurentiu Tudor <laurentiu.tudor@nxp.com> Acked-by: Alex Elder <elder@linaro.org> Acked-by: Max Filippov <jcmvbkbc@gmail.com> # xtensa Acked-by: David Sterba <dsterba@suse.com> Acked-By: Anton Ivanov <anton.ivanov@cambridgegreys.com> Acked-by: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Richard Henderson <rth@twiddle.net> Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru> Cc: Matt Turner <mattst88@gmail.com> 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: Chris Zankel <chris@zankel.net> 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: Jiri Kosina <jikos@kernel.org> 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> Link: https://lore.kernel.org/r/20210505091928.22010-23-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
109 lines
2.3 KiB
C
109 lines
2.3 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Copyright (C) 2019 Axis Communications AB
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*
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* Based on ttyprintk.c:
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* Copyright (C) 2010 Samo Pogacnik
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*/
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#include <linux/console.h>
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#include <linux/module.h>
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#include <linux/tty.h>
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static const struct tty_port_operations ttynull_port_ops;
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static struct tty_driver *ttynull_driver;
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static struct tty_port ttynull_port;
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static int ttynull_open(struct tty_struct *tty, struct file *filp)
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{
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return tty_port_open(&ttynull_port, tty, filp);
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}
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static void ttynull_close(struct tty_struct *tty, struct file *filp)
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{
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tty_port_close(&ttynull_port, tty, filp);
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}
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static void ttynull_hangup(struct tty_struct *tty)
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{
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tty_port_hangup(&ttynull_port);
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}
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static int ttynull_write(struct tty_struct *tty, const unsigned char *buf,
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int count)
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{
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return count;
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}
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static unsigned int ttynull_write_room(struct tty_struct *tty)
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{
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return 65536;
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}
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static const struct tty_operations ttynull_ops = {
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.open = ttynull_open,
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.close = ttynull_close,
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.hangup = ttynull_hangup,
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.write = ttynull_write,
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.write_room = ttynull_write_room,
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};
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static struct tty_driver *ttynull_device(struct console *c, int *index)
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{
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*index = 0;
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return ttynull_driver;
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}
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static struct console ttynull_console = {
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.name = "ttynull",
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.device = ttynull_device,
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};
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static int __init ttynull_init(void)
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{
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struct tty_driver *driver;
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int ret;
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driver = tty_alloc_driver(1,
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TTY_DRIVER_RESET_TERMIOS |
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TTY_DRIVER_REAL_RAW |
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TTY_DRIVER_UNNUMBERED_NODE);
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if (IS_ERR(driver))
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return PTR_ERR(driver);
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tty_port_init(&ttynull_port);
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ttynull_port.ops = &ttynull_port_ops;
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driver->driver_name = "ttynull";
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driver->name = "ttynull";
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driver->type = TTY_DRIVER_TYPE_CONSOLE;
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driver->init_termios = tty_std_termios;
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driver->init_termios.c_oflag = OPOST | OCRNL | ONOCR | ONLRET;
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tty_set_operations(driver, &ttynull_ops);
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tty_port_link_device(&ttynull_port, driver, 0);
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ret = tty_register_driver(driver);
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if (ret < 0) {
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put_tty_driver(driver);
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tty_port_destroy(&ttynull_port);
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return ret;
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}
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ttynull_driver = driver;
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register_console(&ttynull_console);
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return 0;
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}
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static void __exit ttynull_exit(void)
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{
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unregister_console(&ttynull_console);
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tty_unregister_driver(ttynull_driver);
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put_tty_driver(ttynull_driver);
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tty_port_destroy(&ttynull_port);
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}
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module_init(ttynull_init);
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module_exit(ttynull_exit);
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MODULE_LICENSE("GPL v2");
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