From: Timur Tabi Date: Fri, 3 Dec 2010 16:51:43 +0000 (-0600) Subject: watchdog: add CONFIG_WATCHDOG_NOWAYOUT support to PowerPC Book-E watchdog driver X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=5d63c13415db2819590bba975dd023eaa593ddc3;p=linux-beck.git watchdog: add CONFIG_WATCHDOG_NOWAYOUT support to PowerPC Book-E watchdog driver 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 Acked-by: Josh Boyer Signed-off-by: Wim Van Sebroeck --- diff --git a/drivers/watchdog/booke_wdt.c b/drivers/watchdog/booke_wdt.c index d11ffb091b0d..636e013e221e 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; }