From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E0124C43603 for ; Tue, 17 Dec 2019 16:23:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BC33B21582 for ; Tue, 17 Dec 2019 16:23:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728371AbfLQQXV (ORCPT ); Tue, 17 Dec 2019 11:23:21 -0500 Received: from metis.ext.pengutronix.de ([85.220.165.71]:41009 "EHLO metis.ext.pengutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728188AbfLQQXV (ORCPT ); Tue, 17 Dec 2019 11:23:21 -0500 Received: from ptx.hi.pengutronix.de ([2001:67c:670:100:1d::c0]) by metis.ext.pengutronix.de with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1ihFcw-0008Ua-NX; Tue, 17 Dec 2019 17:23:14 +0100 Received: from ukl by ptx.hi.pengutronix.de with local (Exim 4.89) (envelope-from ) id 1ihFcv-0000T1-8r; Tue, 17 Dec 2019 17:23:13 +0100 Date: Tue, 17 Dec 2019 17:23:13 +0100 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= To: Greg Kroah-Hartman Cc: Jacek Anaszewski , Pavel Machek , Dan Murphy , Jiri Slaby , kernel@pengutronix.de, linux-kernel@vger.kernel.org, linux-leds@vger.kernel.org, linux-serial@vger.kernel.org Subject: Re: [PATCH v3 3/3] leds: trigger: implement a tty trigger Message-ID: <20191217162313.5n3v7va5nw5lxloh@pengutronix.de> References: <20191217150736.1479-1-u.kleine-koenig@pengutronix.de> <20191217150736.1479-4-u.kleine-koenig@pengutronix.de> <20191217152724.GA3667595@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20191217152724.GA3667595@kroah.com> User-Agent: NeoMutt/20170113 (1.7.2) X-SA-Exim-Connect-IP: 2001:67c:670:100:1d::c0 X-SA-Exim-Mail-From: ukl@pengutronix.de X-SA-Exim-Scanned: No (on metis.ext.pengutronix.de); SAEximRunCond expanded to false X-PTX-Original-Recipient: linux-kernel@vger.kernel.org Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Dec 17, 2019 at 04:27:24PM +0100, Greg Kroah-Hartman wrote: > On Tue, Dec 17, 2019 at 04:07:36PM +0100, Uwe Kleine-König wrote: > > Usage is as follows: > > > > myled=ledname > > tty=ttyS0 > > > > echo tty > /sys/class/leds/$myled/trigger > > cat /sys/class/tty/$tty/dev > /sys/class/leds/$myled/dev > > Is this the correct instructions? Aren't you looking for a major/minor > number instead in your sysfs file? This is correct, yes, at least it works as intended on my machine. /sys/class/tty/$tty/dev produces $major:$minor and that's what the led-trigger consumes. > > . When this new trigger is active it periodically checks the tty's > > statistics and when it changed since the last check the led is flashed > > once. > > > > Signed-off-by: Uwe Kleine-König > > --- > > drivers/leds/trigger/Kconfig | 7 ++ > > drivers/leds/trigger/Makefile | 1 + > > drivers/leds/trigger/ledtrig-tty.c | 159 +++++++++++++++++++++++++++++ > > 3 files changed, 167 insertions(+) > > create mode 100644 drivers/leds/trigger/ledtrig-tty.c > > > > diff --git a/drivers/leds/trigger/Kconfig b/drivers/leds/trigger/Kconfig > > index ce9429ca6dde..40ff08c93f56 100644 > > --- a/drivers/leds/trigger/Kconfig > > +++ b/drivers/leds/trigger/Kconfig > > @@ -144,4 +144,11 @@ config LEDS_TRIGGER_AUDIO > > the audio mute and mic-mute changes. > > If unsure, say N > > > > +config LEDS_TRIGGER_TTY > > + tristate "LED Trigger for TTY devices" > > + depends on TTY > > + help > > + This allows LEDs to be controlled by activity on ttys which includes > > + serial devices like /dev/ttyS0. > > + > > endif # LEDS_TRIGGERS > > diff --git a/drivers/leds/trigger/Makefile b/drivers/leds/trigger/Makefile > > index 733a83e2a718..25c4db97cdd4 100644 > > --- a/drivers/leds/trigger/Makefile > > +++ b/drivers/leds/trigger/Makefile > > @@ -15,3 +15,4 @@ obj-$(CONFIG_LEDS_TRIGGER_PANIC) += ledtrig-panic.o > > obj-$(CONFIG_LEDS_TRIGGER_NETDEV) += ledtrig-netdev.o > > obj-$(CONFIG_LEDS_TRIGGER_PATTERN) += ledtrig-pattern.o > > obj-$(CONFIG_LEDS_TRIGGER_AUDIO) += ledtrig-audio.o > > +obj-$(CONFIG_LEDS_TRIGGER_TTY) += ledtrig-tty.o > > diff --git a/drivers/leds/trigger/ledtrig-tty.c b/drivers/leds/trigger/ledtrig-tty.c > > new file mode 100644 > > index 000000000000..0157aa0b2ce3 > > --- /dev/null > > +++ b/drivers/leds/trigger/ledtrig-tty.c > > @@ -0,0 +1,159 @@ > > +// SPDX-License-Identifier: GPL-2.0 > > + > > +#include > > +#include > > +#include > > +#include > > +#include > > + > > +struct ledtrig_tty_data { > > + struct led_classdev *led_cdev; > > + struct delayed_work dwork; > > + struct tty_struct *tty; > > + dev_t device; > > + int rx, tx; > > +}; > > + > > +static void ledtrig_tty_halt(struct ledtrig_tty_data *trigger_data) > > +{ > > + cancel_delayed_work_sync(&trigger_data->dwork); > > +} > > + > > +static void ledtrig_tty_restart(struct ledtrig_tty_data *trigger_data) > > +{ > > + if (!trigger_data->tty) > > + return; > > + > > + schedule_delayed_work(&trigger_data->dwork, 0); > > +} > > + > > +static ssize_t dev_show(struct device *dev, > > + struct device_attribute *attr, char *buf) > > +{ > > + struct ledtrig_tty_data *trigger_data = led_trigger_get_drvdata(dev); > > + ssize_t len = 0; > > + > > + if (trigger_data->tty) > > + len = sprintf(buf, "%u\n", trigger_data->device); > > Will that print a dev_t in a format that userspace can make sense of it? > Should you split it up with MAJOR:MINOR instead? Ah, yes, this needs fixing to match the format that is used in .store. > > + > > + return len; > > +} > > + > > +static ssize_t dev_store(struct device *dev, > > + struct device_attribute *attr, const char *buf, > > + size_t size) > > +{ > > + struct ledtrig_tty_data *trigger_data = led_trigger_get_drvdata(dev); > > + struct tty_struct *tty; > > + unsigned major, minor; > > + int ret; > > + > > + if (size == 0 || (size == 1 && buf[0] == '\n')) { > > + tty = NULL; > > + } else { > > + ret = sscanf(buf, "%u:%u", &major, &minor); > > + if (ret < 2) { > > + dev_err(dev, "invalid value\n"); > > Can I DoS the syslog with this? :) Only if you can write to the sysfs file in which case you can DoS the syslog anyhow :-) > > + return -EINVAL; > > + } > > + > > + tty = tty_kopen_shared(MKDEV(major, minor)); > > + if (IS_ERR(tty)) { > > + dev_err(dev, "failed to open tty: %pe\n", tty); > > Same here, dev_dbg() perhaps? > > Other than these minor things, looks good to me. > > Your tty changes are fine, if I can get an ack from the led maintainers > about a working patch 3, I'll be glad to take all 3 in my tree. You'll get a v4 in a moment. Thanks for your prompt reviews. Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | https://www.pengutronix.de/ |