* [RFC 1/2] watchdog: dev: add helper for creating uevent on dev
2016-05-25 13:47 [RFC 0/2] watchdog: pretimeout: userspace governor Wolfram Sang
@ 2016-05-25 13:47 ` Wolfram Sang
2016-05-25 13:47 ` [RFC 2/2] watchdog: pretimeout: add userspace notifier pretimeout governor Wolfram Sang
1 sibling, 0 replies; 3+ messages in thread
From: Wolfram Sang @ 2016-05-25 13:47 UTC (permalink / raw)
To: linux-watchdog
Cc: Wolfram Sang, linux-renesas-soc, Guenter Roeck,
Vladimir Zapolskiy
From: Wolfram Sang <wsa+renesas@sang-engineering.com>
Mechanisms like pretimeout governors may want to notify userspace via
uevents. Add a helper because all the needed data is private to the
watchdog device. To allow calling it in atomic contexts, put actual
signalling to a workqueue.
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
drivers/watchdog/watchdog_dev.c | 20 ++++++++++++++++++++
include/linux/watchdog.h | 3 +++
2 files changed, 23 insertions(+)
diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c
index 9e2e668e1c6b2d..2a7d04034641dc 100644
--- a/drivers/watchdog/watchdog_dev.c
+++ b/drivers/watchdog/watchdog_dev.c
@@ -63,6 +63,7 @@ struct watchdog_core_data {
struct kref kref;
struct cdev cdev;
struct watchdog_device *wdd;
+ struct device *dev;
struct mutex lock;
unsigned long last_keepalive;
unsigned long last_hw_keepalive;
@@ -70,6 +71,7 @@ struct watchdog_core_data {
unsigned long status; /* Internal status bits */
#define _WDOG_DEV_OPEN 0 /* Opened ? */
#define _WDOG_ALLOW_RELEASE 1 /* Did we receive the magic char ? */
+ struct work_struct uevent_work;
};
/* the dev_t structure to store the dynamically allocated watchdog devices */
@@ -821,6 +823,21 @@ static struct miscdevice watchdog_miscdev = {
.fops = &watchdog_fops,
};
+void watchdog_dev_uevent(struct watchdog_device *wdd)
+{
+ queue_work(watchdog_wq, &wdd->wd_data->uevent_work);
+}
+
+static void watchdog_dev_uevent_work(struct work_struct *work)
+{
+ struct watchdog_core_data *wd_data = container_of(work, struct watchdog_core_data,
+ uevent_work);
+
+ mutex_lock(&wd_data->lock);
+ kobject_uevent(&wd_data->dev->kobj, KOBJ_CHANGE);
+ mutex_unlock(&wd_data->lock);
+}
+
/*
* watchdog_cdev_register: register watchdog character device
* @wdd: watchdog device
@@ -849,6 +866,7 @@ static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno)
return -ENODEV;
INIT_DELAYED_WORK(&wd_data->work, watchdog_ping_work);
+ INIT_WORK(&wd_data->uevent_work, watchdog_dev_uevent_work);
if (wdd->id == 0) {
old_wd_data = wd_data;
@@ -968,6 +986,8 @@ int watchdog_dev_register(struct watchdog_device *wdd)
watchdog_cdev_unregister(wdd);
}
+ wdd->wd_data->dev = dev;
+
return ret;
}
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h
index 496e52e5b91fc7..f0f77f06d9813b 100644
--- a/include/linux/watchdog.h
+++ b/include/linux/watchdog.h
@@ -194,6 +194,9 @@ extern int watchdog_init_timeout(struct watchdog_device *wdd,
extern int watchdog_register_device(struct watchdog_device *);
extern void watchdog_unregister_device(struct watchdog_device *);
+/* drivers/watchdog/watchdog_dev.c */
+void watchdog_dev_uevent(struct watchdog_device *wdd);
+
/* drivers/watchdog/watchdog_pretimeout.c */
#ifdef CONFIG_WATCHDOG_PRETIMEOUT_GOV
void watchdog_notify_pretimeout(struct watchdog_device *wdd);
--
2.8.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* [RFC 2/2] watchdog: pretimeout: add userspace notifier pretimeout governor
2016-05-25 13:47 [RFC 0/2] watchdog: pretimeout: userspace governor Wolfram Sang
2016-05-25 13:47 ` [RFC 1/2] watchdog: dev: add helper for creating uevent on dev Wolfram Sang
@ 2016-05-25 13:47 ` Wolfram Sang
1 sibling, 0 replies; 3+ messages in thread
From: Wolfram Sang @ 2016-05-25 13:47 UTC (permalink / raw)
To: linux-watchdog
Cc: Wolfram Sang, linux-renesas-soc, Guenter Roeck,
Vladimir Zapolskiy
From: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Userspace notifier watchdog pretimeout governor, on watchdog
pretimeout event sends a notification to userspace for further
handling.
Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
---
drivers/watchdog/Kconfig | 16 +++++++++++
drivers/watchdog/Makefile | 1 +
drivers/watchdog/pretimeout_userspace.c | 47 +++++++++++++++++++++++++++++++++
drivers/watchdog/watchdog_pretimeout.h | 2 ++
4 files changed, 66 insertions(+)
create mode 100644 drivers/watchdog/pretimeout_userspace.c
diff --git a/drivers/watchdog/Kconfig b/drivers/watchdog/Kconfig
index 3682ae9d8a50ca..e69c17f518ef43 100644
--- a/drivers/watchdog/Kconfig
+++ b/drivers/watchdog/Kconfig
@@ -1800,6 +1800,15 @@ config WATCHDOG_PRETIMEOUT_DEFAULT_GOV_NOOP
governor is selected by a user, write a short message to
the kernel log buffer and don't do any system changes.
+config WATCHDOG_PRETIMEOUT_DEFAULT_GOV_USERSPACE
+ bool "userspace"
+ select WATCHDOG_PRETIMEOUT_GOV_USERSPACE
+ help
+ Use userspace watchdog pretimeout governor by default,
+ the governor sends a device state change uevent
+ notification, if a pretimeout event a reported by a
+ watchdog.
+
endchoice
config WATCHDOG_PRETIMEOUT_GOV_PANIC
@@ -1816,6 +1825,13 @@ config WATCHDOG_PRETIMEOUT_GOV_NOOP
governor, only an informational message is added to the
kernel log buffer, if watchdog pretimeout is happened.
+config WATCHDOG_PRETIMEOUT_GOV_USERSPACE
+ tristate "Userspace notifier watchdog pretimeout governor"
+ help
+ Userspace notifier watchdog pretimeout governor, on watchdog
+ pretimeout event send a notification to userspace for
+ further handling.
+
endif # WATCHDOG_PRETIMEOUT_GOV
endif # WATCHDOG
diff --git a/drivers/watchdog/Makefile b/drivers/watchdog/Makefile
index 9330e4cabd8f9c..23423b8b73620c 100644
--- a/drivers/watchdog/Makefile
+++ b/drivers/watchdog/Makefile
@@ -10,6 +10,7 @@ watchdog-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV) += watchdog_pretimeout.o
obj-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV_PANIC) += pretimeout_panic.o
obj-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV_NOOP) += pretimeout_noop.o
+obj-$(CONFIG_WATCHDOG_PRETIMEOUT_GOV_USERSPACE) += pretimeout_userspace.o
# Only one watchdog can succeed. We probe the ISA/PCI/USB based
# watchdog-cards first, then the architecture specific watchdog
diff --git a/drivers/watchdog/pretimeout_userspace.c b/drivers/watchdog/pretimeout_userspace.c
new file mode 100644
index 00000000000000..cf7b03765f3254
--- /dev/null
+++ b/drivers/watchdog/pretimeout_userspace.c
@@ -0,0 +1,47 @@
+/*
+ * Copyright (C) 2015 Mentor Graphics
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/watchdog.h>
+
+#include "watchdog_pretimeout.h"
+
+/**
+ * pretimeout_userspace - Notify userspace on watchdog pretimeout event
+ * @wdd - watchdog_device
+ *
+ * Send watchdog device uevent to userspace to handle pretimeout event
+ */
+static void pretimeout_userspace(struct watchdog_device *wdd)
+{
+ watchdog_dev_uevent(wdd);
+}
+
+static struct watchdog_governor watchdog_gov_userspace = {
+ .name = "userspace",
+ .pretimeout = pretimeout_userspace,
+ .owner = THIS_MODULE,
+};
+
+static int __init watchdog_gov_userspace_register(void)
+{
+ return watchdog_register_governor(&watchdog_gov_userspace);
+}
+module_init(watchdog_gov_userspace_register);
+
+static void __exit watchdog_gov_userspace_unregister(void)
+{
+ watchdog_unregister_governor(&watchdog_gov_userspace);
+}
+module_exit(watchdog_gov_userspace_unregister);
+
+MODULE_AUTHOR("Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>");
+MODULE_DESCRIPTION("Userspace notifier watchdog pretimeout governor");
+MODULE_LICENSE("GPL");
diff --git a/drivers/watchdog/watchdog_pretimeout.h b/drivers/watchdog/watchdog_pretimeout.h
index 2e60450a2be64e..8365cd78f2507b 100644
--- a/drivers/watchdog/watchdog_pretimeout.h
+++ b/drivers/watchdog/watchdog_pretimeout.h
@@ -23,6 +23,8 @@ void watchdog_unregister_governor(struct watchdog_governor *gov);
#define WATCHDOG_PRETIMEOUT_DEFAULT_GOV "panic"
#elif IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_DEFAULT_GOV_NOOP)
#define WATCHDOG_PRETIMEOUT_DEFAULT_GOV "noop"
+#elif IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_DEFAULT_GOV_USERSPACE)
+#define WATCHDOG_PRETIMEOUT_DEFAULT_GOV "userspace"
#else
#error "Default watchdog pretimeout governor is not set."
#endif
--
2.8.1
^ permalink raw reply related [flat|nested] 3+ messages in thread