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-rw-r--r--drivers/watchdog/watchdog_dev.c18
1 files changed, 13 insertions, 5 deletions
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index db40c6c79ef8..ac20f92347b1 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -98,11 +98,18 @@ static int watchdog_start(struct watchdog_device *wddev)
98 * Stop the watchdog if it is still active and unmark it active. 98 * Stop the watchdog if it is still active and unmark it active.
99 * This function returns zero on success or a negative errno code for 99 * This function returns zero on success or a negative errno code for
100 * failure. 100 * failure.
101 * If the 'nowayout' feature was set, the watchdog cannot be stopped.
101 */ 102 */
102 103
103static int watchdog_stop(struct watchdog_device *wddev) 104static int watchdog_stop(struct watchdog_device *wddev)
104{ 105{
105 int err; 106 int err = -EBUSY;
107
108 if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) {
109 pr_info("%s: nowayout prevents watchdog to be stopped!\n",
110 wdd->info->identity);
111 return err;
112 }
106 113
107 if (test_bit(WDOG_ACTIVE, &wdd->status)) { 114 if (test_bit(WDOG_ACTIVE, &wdd->status)) {
108 err = wddev->ops->stop(wddev); 115 err = wddev->ops->stop(wddev);
@@ -123,7 +130,7 @@ static int watchdog_stop(struct watchdog_device *wddev)
123 * 130 *
124 * A write to a watchdog device is defined as a keepalive ping. 131 * A write to a watchdog device is defined as a keepalive ping.
125 * Writing the magic 'V' sequence allows the next close to turn 132 * Writing the magic 'V' sequence allows the next close to turn
126 * off the watchdog. 133 * off the watchdog (if 'nowayout' is not set).
127 */ 134 */
128 135
129static ssize_t watchdog_write(struct file *file, const char __user *data, 136static ssize_t watchdog_write(struct file *file, const char __user *data,
@@ -271,8 +278,8 @@ out:
271 * @file: file handle to device 278 * @file: file handle to device
272 * 279 *
273 * This is the code for when /dev/watchdog gets closed. We will only 280 * This is the code for when /dev/watchdog gets closed. We will only
274 * stop the watchdog when we have received the magic char, else the 281 * stop the watchdog when we have received the magic char (and nowayout
275 * watchdog will keep running. 282 * was not set), else the watchdog will keep running.
276 */ 283 */
277 284
278static int watchdog_release(struct inode *inode, struct file *file) 285static int watchdog_release(struct inode *inode, struct file *file)
@@ -281,7 +288,8 @@ static int watchdog_release(struct inode *inode, struct file *file)
281 288
282 /* 289 /*
283 * We only stop the watchdog if we received the magic character 290 * We only stop the watchdog if we received the magic character
284 * or if WDIOF_MAGICCLOSE is not set 291 * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then
292 * watchdog_stop will fail.
285 */ 293 */
286 if (test_and_clear_bit(WDOG_ALLOW_RELEASE, &wdd->status) || 294 if (test_and_clear_bit(WDOG_ALLOW_RELEASE, &wdd->status) ||
287 !(wdd->info->options & WDIOF_MAGICCLOSE)) 295 !(wdd->info->options & WDIOF_MAGICCLOSE))