1 files changed, 27 insertions, 26 deletions

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index d7ebdf4cea9..18bb15776c5 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -27,7 +27,7 @@
 #include <asm/irq_regs.h>
 #include <linux/perf_event.h>
 
-int watchdog_enabled;
+int watchdog_enabled = 1;
 int __read_mostly softlockup_thresh = 60;
 
 static DEFINE_PER_CPU(unsigned long, watchdog_touch_ts);
@@ -43,9 +43,6 @@ static DEFINE_PER_CPU(unsigned long, hrtimer_interrupts_saved);
 static DEFINE_PER_CPU(struct perf_event *, watchdog_ev);
 #endif
 
-static int no_watchdog;
-
-
 /* boot commands */
 /*
  * Should we panic when a soft-lockup or hard-lockup occurs:
@@ -58,7 +55,7 @@ static int __init hardlockup_panic_setup(char *str)
         if (!strncmp(str, "panic", 5))
                 hardlockup_panic = 1;
         else if (!strncmp(str, "0", 1))
-                no_watchdog = 1;
+                watchdog_enabled = 0;
         return 1;
 }
 __setup("nmi_watchdog=", hardlockup_panic_setup);
@@ -77,7 +74,7 @@ __setup("softlockup_panic=", softlockup_panic_setup);
 
 static int __init nowatchdog_setup(char *str)
 {
-        no_watchdog = 1;
+        watchdog_enabled = 0;
         return 1;
 }
 __setup("nowatchdog", nowatchdog_setup);
@@ -85,7 +82,7 @@ __setup("nowatchdog", nowatchdog_setup);
 /* deprecated */
 static int __init nosoftlockup_setup(char *str)
 {
-        no_watchdog = 1;
+        watchdog_enabled = 0;
         return 1;
 }
 __setup("nosoftlockup", nosoftlockup_setup);
@@ -366,8 +363,14 @@ static int watchdog_nmi_enable(int cpu)
                 goto out_save;
         }
 
-        printk(KERN_ERR "NMI watchdog disabled for cpu%i: unable to create perf event: %ld\n",
-               cpu, PTR_ERR(event));
+
+        /* vary the KERN level based on the returned errno */
+        if (PTR_ERR(event) == -EOPNOTSUPP)
+                printk(KERN_INFO "NMI watchdog disabled (cpu%i): not supported (no LAPIC?)\n", cpu);
+        else if (PTR_ERR(event) == -ENOENT)
+                printk(KERN_WARNING "NMI watchdog disabled (cpu%i): hardware events not enabled\n", cpu);
+        else
+                printk(KERN_ERR "NMI watchdog disabled (cpu%i): unable to create perf event: %ld\n", cpu, PTR_ERR(event));
         return PTR_ERR(event);
 
         /* success path */
@@ -432,9 +435,6 @@ static int watchdog_enable(int cpu)
                 wake_up_process(p);
         }
 
-        /* if any cpu succeeds, watchdog is considered enabled for the system */
-        watchdog_enabled = 1;
-
         return 0;
 }
 
@@ -462,12 +462,16 @@ static void watchdog_disable(int cpu)
 static void watchdog_enable_all_cpus(void)
 {
         int cpu;
-        int result = 0;
+
+        watchdog_enabled = 0;
 
         for_each_online_cpu(cpu)
-                result += watchdog_enable(cpu);
+                if (!watchdog_enable(cpu))
+                        /* if any cpu succeeds, watchdog is considered
+                           enabled for the system */
+                        watchdog_enabled = 1;
 
-        if (result)
+        if (!watchdog_enabled)
                 printk(KERN_ERR "watchdog: failed to be enabled on some cpus\n");
 
 }
@@ -476,9 +480,6 @@ static void watchdog_disable_all_cpus(void)
 {
         int cpu;
 
-        if (no_watchdog)
-                return;
-
         for_each_online_cpu(cpu)
                 watchdog_disable(cpu);
 
@@ -498,10 +499,12 @@ int proc_dowatchdog_enabled(struct ctl_table *table, int write,
 {
         proc_dointvec(table, write, buffer, length, ppos);
 
-        if (watchdog_enabled)
-                watchdog_enable_all_cpus();
-        else
-                watchdog_disable_all_cpus();
+        if (write) {
+                if (watchdog_enabled)
+                        watchdog_enable_all_cpus();
+                else
+                        watchdog_disable_all_cpus();
+        }
         return 0;
 }
 
@@ -530,7 +533,8 @@ cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
                 break;
         case CPU_ONLINE:
         case CPU_ONLINE_FROZEN:
-                err = watchdog_enable(hotcpu);
+                if (watchdog_enabled)
+                        err = watchdog_enable(hotcpu);
                 break;
 #ifdef CONFIG_HOTPLUG_CPU
         case CPU_UP_CANCELED:
@@ -555,9 +559,6 @@ void __init lockup_detector_init(void)
         void *cpu = (void *)(long)smp_processor_id();
         int err;
 
-        if (no_watchdog)
-                return;
-
         err = cpu_callback(&cpu_nfb, CPU_UP_PREPARE, cpu);
         WARN_ON(notifier_to_errno(err));