Normally, the watchdog is disabled when dev/watchdog is closed, but if
CONFIG_WATCHDOG_NOWAYOUT is defined, then it means that the watchdog should
remain enabled. So we should disable it only if CONFIG_WATCHDOG_NOWAYOUT is
not defined.
Also ensure that /dev/watchdog is only opened by one process at a time. That
way, a second process can't accidentally disable the watchdog while the first
process has it open. There shouldn't be any need for more than one process to
open /dev/watchdog anyway.
Signed-off-by: Timur Tabi <ti...@freescale.com>
---
Kumar, please pick up this patch for 2.6.37.
drivers/watchdog/booke_wdt.c | 16 ++++++++++++++++
1 files changed, 16 insertions(+), 0 deletions(-)
diff --git a/drivers/watchdog/booke_wdt.c b/drivers/watchdog/booke_wdt.c
index d11ffb0..636e013 100644
--- a/drivers/watchdog/booke_wdt.c
+++ b/drivers/watchdog/booke_wdt.c
@@ -193,8 +193,15 @@ static long booke_wdt_ioctl(struct file *file,
return 0;
}
+/* wdt_is_active stores wether or not the /dev/watchdog device is opened */
+static unsigned long wdt_is_active;
+
static int booke_wdt_open(struct inode *inode, struct file *file)
{
+ /* /dev/watchdog can only be opened once */
+ if (test_and_set_bit(0, &wdt_is_active))
+ return -EBUSY;
+
spin_lock(&booke_wdt_lock);
if (booke_wdt_enabled == 0) {
booke_wdt_enabled = 1;
@@ -210,8 +217,17 @@ static int booke_wdt_open(struct inode *inode, struct file
*file)
static int booke_wdt_release(struct inode *inode, struct file *file)
{
+#ifndef CONFIG_WATCHDOG_NOWAYOUT
+ /* Normally, the watchdog is disabled when /dev/watchdog is closed, but
+ * if CONFIG_WATCHDOG_NOWAYOUT is defined, then it means that the
+ * watchdog should remain enabled. So we disable it only if
+ * CONFIG_WATCHDOG_NOWAYOUT is not defined.
+ */
on_each_cpu(__booke_wdt_disable, NULL, 0);
booke_wdt_enabled = 0;
+#endif
+
+ clear_bit(0, &wdt_is_active);
return 0;
}
--
1.7.2.3
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