BMC/Intel-BMC/linux.git/drivers/watchdog/watchdog_dev.c, branch dev-4.4

watchdog: core: propagate ping error code to the user space

2015-11-03T13:36:14+00:00

Watchdog ping return errors are ignored by watchdog core, Whatchdog daemon should be informed about possible hardware error or underlaying device driver get unregistered. Signed-off-by: Alexander Usyskin Signed-off-by: Tomas Winkler Reviewed-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck

watchdog: watchdog_dev: Use single variable name for struct watchdog_device

2015-11-03T13:36:09+00:00

The current code uses 'wdd', wddev', and 'watchdog' as variable names for struct watchdog_device. This is confusing and makes it difficult to enhance the code. Replace it all with 'wdd'. Signed-off-by: Guenter Roeck Cc: Timo Kokkonen Acked-by: Uwe Kleine-König Signed-off-by: Wim Van Sebroeck

watchdog: core: don't try to stop device if not running

2013-07-11T19:14:39+00:00

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 Reviewed-by: Guenter Roeck Signed-off-by: Wim Van Sebroeck

watchdog: Fix race condition in registration code

2013-05-09T06:13:41+00:00

A race condition exists when registering the first watchdog device. Sequence of events: - watchdog_register_device calls watchdog_dev_register - watchdog_dev_register creates the watchdog misc device by calling misc_register. At that time, the matching character device (/dev/watchdog0) does not yet exist, and old_wdd is not set either. - Userspace gets an event and opens /dev/watchdog - watchdog_open is called and sets wdd = old_wdd, which is still NULL, and tries to dereference it. This causes the kernel to panic. Seen with systemd trying to open /dev/watchdog immediately after it was created. Reported-by: Arkadiusz Miskiewicz Signed-off-by: Guenter Roeck Tested-by: Arkadiusz Miskiewicz Signed-off-by: Wim Van Sebroeck

watchdog: core: dt: add support for the timeout-sec dt property

2013-03-01T11:48:36+00:00

Add support for watchdog drivers to initialize/set the timeout field of the watchdog_device structure. The timeout field is initialised either with the module timeout parameter value (if valid) or with the timeout-sec dt property (if valid). If both are invalid the initial value is unchanged. Signed-off-by: Fabio Porcedda Acked-by: Nicolas Ferre Signed-off-by: Wim Van Sebroeck

watchdog: core: fix WDIOC_GETSTATUS return value

2012-06-28T18:40:56+00:00

In commit 7a87982420e5e126bfefeb42232d1fd92052794e we added a wrapper for the WDIOC_GETSTATUS ioctl call. The code results however in a different behaviour: it returns an error if the driver doesn't support the status operation. This is not according to the API that says that when we don't support the status operation, that we just should return a 0 value. Only when the device isn't there anymore, we should return an error. Signed-off-by: Wim Van Sebroeck

watchdog: Add support for dynamically allocated watchdog_device structs

2012-05-30T05:55:31+00:00

If a driver's watchdog_device struct is part of a dynamically allocated struct (which it often will be), merely locking the module is not enough, even with a drivers module locked, the driver can be unbound from the device, examples: 1) The root user can unbind it through sysfd 2) The i2c bus master driver being unloaded for an i2c watchdog I will gladly admit that these are corner cases, but we still need to handle them correctly. The fix for this consists of 2 parts: 1) Add ref / unref operations, so that the driver can refcount the struct holding the watchdog_device struct and delay freeing it until any open filehandles referring to it are closed 2) Most driver operations will do IO on the device and the driver should not do any IO on the device after it has been unbound. Rather then letting each driver deal with this internally, it is better to ensure at the watchdog core level that no operations (other then unref) will get called after the driver has called watchdog_unregister_device(). This actually is the bulk of this patch. Signed-off-by: Hans de Goede Signed-off-by: Wim Van Sebroeck

watchdog: Add Locking support

2012-05-30T05:55:23+00:00

This patch fixes some potential multithreading issues, despite only allowing one process to open the /dev/watchdog device, we can still get called multiple times at the same time, since a program could be using thread, or could share the fd after a fork. This causes 2 potential problems: 1) watchdog_start / open do an unlocked test_n_set / test_n_clear, if these 2 race, the watchdog could be stopped while the active bit indicates it is running or visa versa. 2) Most watchdog_dev drivers probably assume that only one watchdog-op will get called at a time, this is not necessary true atm. Signed-off-by: Hans de Goede Signed-off-by: Wim Van Sebroeck

watchdog: watchdog_dev: Rewrite wrapper code

2012-05-30T05:55:17+00:00

Rewrite and extend the wrapper code so that we can easily introduce locking (this to be able to prevent potential multithreading issues). Signed-off-by: Hans de Goede Signed-off-by: Wim Van Sebroeck

watchdog: use dev_ functions

2012-05-30T05:54:57+00:00

While they are registered all our watchdogs now have a valid device object so we can in turn use that to report problems nicely. Signed-off-by: Alan Cox Signed-off-by: Hans de Goede Signed-off-by: Wim Van Sebroeck