From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail1.bemta7.messagelabs.com ([216.82.254.97]:52726 "EHLO mail1.bemta7.messagelabs.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162004Ab3DEQRK (ORCPT ); Fri, 5 Apr 2013 12:17:10 -0400 Message-ID: <515EF748.6060504@digi.com> Date: Fri, 5 Apr 2013 18:09:44 +0200 From: Hector Palacios MIME-Version: 1.0 To: , CC: "linux-kernel@vger.kernel.org" Subject: [PATCH RFC] watchdog: core: don't try to stop device if not running Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-watchdog-owner@vger.kernel.org List-Id: linux-watchdog@vger.kernel.org A watchdog device may be stopped from userspace using WDIOC_SETOPTIONS ioctl and flag WDIOS_DISABLECARD. If the device is closed after this operation, watchdog_release() is called and status bits checked for stopping it. Besides, if the device has not been unregistered a critical message "watchdog did not stop!" is printed, although the ioctl may have successfully stopped it already. Without the patch a user application sample code like this will successfully stop the watchdog, but the kernel will output the message "watchdog did not stop!": wd_fd = open("/dev/watchdog", O_RDWR); flags = WDIOS_DISABLECARD; ioctl(wd_fd, WDIOC_SETOPTIONS, &flags); close(wd_fd); Signed-off-by: Hector Palacios --- drivers/watchdog/watchdog_dev.c | 38 +++++++++++++++++++++----------------- 1 file changed, 21 insertions(+), 17 deletions(-) diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index ef8edec..adadbdd 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -463,24 +463,28 @@ out: static int watchdog_release(struct inode *inode, struct file *file) { struct watchdog_device *wdd = file->private_data; - int err = -EBUSY; - /* - * We only stop the watchdog if we received the magic character - * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then - * watchdog_stop will fail. - */ - if (test_and_clear_bit(WDOG_ALLOW_RELEASE, &wdd->status) || - !(wdd->info->options & WDIOF_MAGICCLOSE)) - err = watchdog_stop(wdd); - - /* If the watchdog was not stopped, send a keepalive ping */ - if (err < 0) { - mutex_lock(&wdd->lock); - if (!test_bit(WDOG_UNREGISTERED, &wdd->status)) - dev_crit(wdd->dev, "watchdog did not stop!\n"); - mutex_unlock(&wdd->lock); - watchdog_ping(wdd); + if (test_bit(WDOG_ACTIVE, &wdd->status)) { + int err = -EBUSY; + + /* + * We only stop the watchdog if we received the magic character + * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then + * watchdog_stop will fail. + */ + if (test_and_clear_bit(WDOG_ALLOW_RELEASE, &wdd->status) || + !(wdd->info->options & WDIOF_MAGICCLOSE)) { + err = watchdog_stop(wdd); + } + + /* If the watchdog was not stopped, send a keepalive ping */ + if (err < 0) { + mutex_lock(&wdd->lock); + if (!test_bit(WDOG_UNREGISTERED, &wdd->status)) + dev_crit(wdd->dev, "watchdog did not stop!\n"); + mutex_unlock(&wdd->lock); + watchdog_ping(wdd); + } } /* Allow the owner module to be unloaded again */ -- 1.7.9.5