watchdog: add CONFIG_WATCHDOG_NOWAYOUT support to PowerPC Book-E watchdog driver (5d63c134) · Commits · 戴 / test

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 <timur@freescale.com> Acked-by:

Josh Boyer <jwboyer@linux.vnet.ibm.com> Signed-off-by:

Wim Van Sebroeck <wim@iguana.be>

drivers/watchdog/booke_wdt.c

+16 −0

Original line number	Diff line number	Diff line
		@@ -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;
		}

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