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| author |   Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2019-11-05 21:51:18 +0100 |
|---|---|---|
| committer |   Wim Van Sebroeck <wim@linux-watchdog.org> | 2019-11-18 19:53:43 +0100 |
| commit | bc44fa734cef28e7ddb26bbf9e75e7f7449c9db2 (patch) | |
| tree | e7c5aaf051523dfd27b25f47c377b6cc8093ff72 /drivers/watchdog | |
| parent | watchdog: prevent deferral of watchdogd wakeup on RT (diff) | |
| download | linux-dev-bc44fa734cef28e7ddb26bbf9e75e7f7449c9db2.tar.xz linux-dev-bc44fa734cef28e7ddb26bbf9e75e7f7449c9db2.zip | |
watchdog: make nowayout sysfs file writable
It can be useful to delay setting the nowayout feature for a watchdog
device. Moreover, not every driver (notably gpio_wdt) implements a
nowayout module parameter/otherwise respects CONFIG_WATCHDOG_NOWAYOUT,
and modifying those drivers carries a risk of causing a regression for
someone who has two watchdog devices, sets CONFIG_WATCHDOG_NOWAYOUT
and somehow relies on the gpio_wdt driver being ignorant of
that (i.e., allowing one to gracefully close a gpio_wdt but not the
other watchdog in the system).
So instead, simply make the nowayout sysfs file writable. Obviously,
setting nowayout is a one-way street.
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20191105205118.11359-1-linux@rasmusvillemoes.dk
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>
Diffstat (limited to 'drivers/watchdog')
| -rw-r--r-- | drivers/watchdog/watchdog_dev.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 62483a99105c..4feecd14e9ab 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -452,7 +452,26 @@ static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status)); } -static DEVICE_ATTR_RO(nowayout); + +static ssize_t nowayout_store(struct device *dev, struct device_attribute *attr, + const char *buf, size_t len) +{ + struct watchdog_device *wdd = dev_get_drvdata(dev); + unsigned int value; + int ret; + + ret = kstrtouint(buf, 0, &value); + if (ret) + return ret; + if (value > 1) + return -EINVAL; + /* nowayout cannot be disabled once set */ + if (test_bit(WDOG_NO_WAY_OUT, &wdd->status) && !value) + return -EPERM; + watchdog_set_nowayout(wdd, value); + return len; +} +static DEVICE_ATTR_RW(nowayout); static ssize_t status_show(struct device *dev, struct device_attribute *attr, char *buf) |