diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2012-05-22 11:40:26 +0200 |
|---|---|---|
| committer | Wim Van Sebroeck <wim@iguana.be> | 2012-05-30 07:55:23 +0200 |
| commit | f4e9c82f64b524314a390b13d3ba7d483f09258f (patch) | |
| tree | 82d688ae7782234dc01c6a340596bac21531aae4 /include | |
| parent | 7a87982420e5e126bfefeb42232d1fd92052794e (diff) | |
watchdog: Add Locking support
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 <hdegoede@redhat.com>
Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/watchdog.h | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/watchdog.h b/include/linux/watchdog.h index c3545c5d918a..da1dc1b52744 100644 --- a/include/linux/watchdog.h +++ b/include/linux/watchdog.h @@ -104,6 +104,7 @@ struct watchdog_ops { * @min_timeout:The watchdog devices minimum timeout value. * @max_timeout:The watchdog devices maximum timeout value. * @driver-data:Pointer to the drivers private data. + * @lock: Lock for watchdog core internal use only. * @status: Field that contains the devices internal status bits. * * The watchdog_device structure contains all information about a @@ -111,6 +112,9 @@ struct watchdog_ops { * * The driver-data field may not be accessed directly. It must be accessed * via the watchdog_set_drvdata and watchdog_get_drvdata helpers. + * + * The lock field is for watchdog core internal use only and should not be + * touched. */ struct watchdog_device { int id; @@ -124,6 +128,7 @@ struct watchdog_device { unsigned int min_timeout; unsigned int max_timeout; void *driver_data; + struct mutex lock; unsigned long status; /* Bit numbers for status flags */ #define WDOG_ACTIVE 0 /* Is the watchdog running/active */ |