watchdog: Rename confusing state variable

We have two very conflicting state variable names in the
watchdog:

* watchdog_enabled: This one reflects the user interface. It's
set to 1 by default and can be overriden with boot options
or sysctl/procfs interface.

* watchdog_disabled: This is the internal toggle state that
tells if watchdog threads, timers and NMI events are currently
running or not. This state mostly depends on the user settings.
It's a convenient state latch.

Now we really need to find clearer names because those
are just too confusing to encourage deep review.

watchdog_enabled now becomes watchdog_user_enabled to reflect
its purpose as an interface.

watchdog_disabled becomes watchdog_running to suggest its
role as a pure internal state.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Anish Singh <anish198519851985@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Don Zickus <dzickus@redhat.com>

diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index db50840..6a45fb5 100644 (file)
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -46,7 +46,7 @@ static inline bool trigger_all_cpu_backtrace(void)
 #ifdef CONFIG_LOCKUP_DETECTOR
 int hw_nmi_is_cpu_stuck(struct pt_regs *);
 u64 hw_nmi_get_sample_period(int watchdog_thresh);
-extern int watchdog_enabled;
+extern int watchdog_user_enabled;
 extern int watchdog_thresh;
 struct ctl_table;
 extern int proc_dowatchdog(struct ctl_table *, int ,

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 9edcf45..b080565 100644 (file)
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -801,7 +801,7 @@ static struct ctl_table kern_table[] = {
 #if defined(CONFIG_LOCKUP_DETECTOR)
        {
                .procname       = "watchdog",
-               .data           = &watchdog_enabled,
+               .data           = &watchdog_user_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dowatchdog,
@@ -828,7 +828,7 @@ static struct ctl_table kern_table[] = {
        },
        {
                .procname       = "nmi_watchdog",
-               .data           = &watchdog_enabled,
+               .data           = &watchdog_user_enabled,
                .maxlen         = sizeof (int),
                .mode           = 0644,
                .proc_handler   = proc_dowatchdog,

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 52c9a9b..51c4f34 100644 (file)
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -29,9 +29,9 @@
 #include <linux/kvm_para.h>
 #include <linux/perf_event.h>
 
-int watchdog_enabled = 1;
+int watchdog_user_enabled = 1;
 int __read_mostly watchdog_thresh = 10;
-static int __read_mostly watchdog_disabled = 1;
+static int __read_mostly watchdog_running;
 static u64 __read_mostly sample_period;
 
 static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
@@ -63,7 +63,7 @@ static int __init hardlockup_panic_setup(char *str)
        else if (!strncmp(str, "nopanic", 7))
                hardlockup_panic = 0;
        else if (!strncmp(str, "0", 1))
-               watchdog_enabled = 0;
+               watchdog_user_enabled = 0;
        return 1;
 }
 __setup("nmi_watchdog=", hardlockup_panic_setup);
@@ -82,7 +82,7 @@ __setup("softlockup_panic=", softlockup_panic_setup);
 
 static int __init nowatchdog_setup(char *str)
 {
-       watchdog_enabled = 0;
+       watchdog_user_enabled = 0;
        return 1;
 }
 __setup("nowatchdog", nowatchdog_setup);
@@ -90,7 +90,7 @@ __setup("nowatchdog", nowatchdog_setup);
 /* deprecated */
 static int __init nosoftlockup_setup(char *str)
 {
-       watchdog_enabled = 0;
+       watchdog_user_enabled = 0;
        return 1;
 }
 __setup("nosoftlockup", nosoftlockup_setup);
@@ -158,7 +158,7 @@ void touch_all_softlockup_watchdogs(void)
 #ifdef CONFIG_HARDLOCKUP_DETECTOR
 void touch_nmi_watchdog(void)
 {
-       if (watchdog_enabled) {
+       if (watchdog_user_enabled) {
                unsigned cpu;
 
                for_each_present_cpu(cpu) {
@@ -490,12 +490,12 @@ static int watchdog_enable_all_cpus(void)
 {
        int err = 0;
 
-       if (watchdog_disabled) {
+       if (!watchdog_running) {
                err = smpboot_register_percpu_thread(&watchdog_threads);
                if (err)
                        pr_err("Failed to create watchdog threads, disabled\n");
                else
-                       watchdog_disabled = 0;
+                       watchdog_running = 1;
        }
 
        return err;
@@ -506,8 +506,8 @@ static int watchdog_enable_all_cpus(void)
 #ifdef CONFIG_SYSCTL
 static void watchdog_disable_all_cpus(void)
 {
-       if (!watchdog_disabled) {
-               watchdog_disabled = 1;
+       if (watchdog_running) {
+               watchdog_running = 0;
                smpboot_unregister_percpu_thread(&watchdog_threads);
        }
 }
@@ -522,7 +522,7 @@ int proc_dowatchdog(struct ctl_table *table, int write,
        int err, old_thresh, old_enabled;
 
        old_thresh = ACCESS_ONCE(watchdog_thresh);
-       old_enabled = ACCESS_ONCE(watchdog_enabled);
+       old_enabled = ACCESS_ONCE(watchdog_user_enabled);
 
        err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
        if (err || !write)
@@ -531,10 +531,10 @@ int proc_dowatchdog(struct ctl_table *table, int write,
        set_sample_period();
        /*
         * Watchdog threads shouldn't be enabled if they are
-        * disabled. The 'watchdog_disabled' variable check in
+        * disabled. The 'watchdog_running' variable check in
         * watchdog_*_all_cpus() function takes care of this.
         */
-       if (watchdog_enabled && watchdog_thresh)
+       if (watchdog_user_enabled && watchdog_thresh)
                err = watchdog_enable_all_cpus();
        else
                watchdog_disable_all_cpus();
@@ -542,7 +542,7 @@ int proc_dowatchdog(struct ctl_table *table, int write,
        /* Restore old values on failure */
        if (err) {
                watchdog_thresh = old_thresh;
-               watchdog_enabled = old_enabled;
+               watchdog_user_enabled = old_enabled;
        }
 
        return err;
@@ -553,6 +553,6 @@ void __init lockup_detector_init(void)
 {
        set_sample_period();
 
-       if (watchdog_enabled)
+       if (watchdog_user_enabled)
                watchdog_enable_all_cpus();
 }