[tip:perf/core] watchdog: Add comments to explain the watchdog_disabled variable

[tip-bot for anish kumar <tipbot@zytor.com>]

Commit-ID:  b66a2356d7108a15b8b5c9b8e6213e05ead22cd6
Gitweb:     http://git.kernel.org/tip/b66a2356d7108a15b8b5c9b8e6213e05ead22cd6
Author:     anish kumar <anish198519851985@gmail.com>
AuthorDate: Tue, 12 Mar 2013 14:44:08 -0400
Committer:  Ingo Molnar <mingo@kernel.org>
CommitDate: Thu, 14 Mar 2013 08:24:05 +0100

watchdog: Add comments to explain the watchdog_disabled variable

The watchdog_disabled flag is a bit cryptic. However it's
usefulness is multifold. Uses are:

 1. Check if smpboot_register_percpu_thread function passed.

 2. Makes sure that user enables and disables the watchdog in
    sequence i.e. enable watchdog->disable watchdog->enable watchdog
    Unlike enable watchdog->enable watchdog which is wrong.

Signed-off-by: anish kumar <anish198519851985@gmail.com>
[small text cleanups]
Signed-off-by: Don Zickus <dzickus@redhat.com>
Cc: chuansheng.liu@intel.com
Cc: paulmck@linux.vnet.ibm.com
Link: http://lkml.kernel.org/r/1363113848-18344-1-git-send-email-dzickus@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 kernel/watchdog.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 4a94467..05039e3 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -517,6 +517,11 @@ int proc_dowatchdog(struct ctl_table *table, int write,
 		return ret;
 
 	set_sample_period();
+	/*
+	 * Watchdog threads shouldn't be enabled if they are
+	 * disabled. The 'watchdog_disabled' variable check in
+	 * watchdog_*_all_cpus() function takes care of this.
+	 */
 	if (watchdog_enabled && watchdog_thresh)
 		watchdog_enable_all_cpus();
 	else