watchdog: move watchdog sysctl interface to watchdog.c

The kernel/sysctl.c is a kitchen sink where everyone leaves
their dirty dishes, this makes it very difficult to maintain.

To help with this maintenance let's start by moving sysctls to
places where they actually belong. The proc sysctl maintainers
do not want to know what sysctl knobs you wish to add for your own
piece of code, we just care about the core logic of proc sysctl.

So, move the watchdog syscl interface to watchdog.c.
Use register_sysctl() to register the sysctl interface to avoid
merge conflicts when different features modify sysctl.c at the
same time.

Signed-off-by: Xiaoming Ni <nixiaoming@huawei.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
[mcgrof: justify the move on the commit log]
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

2 files changed, 101 insertions, 96 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 9fc6a5222cee0..8d5bcf1f08f3f 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -102,16 +102,10 @@
 #ifdef CONFIG_STACKLEAK_RUNTIME_DISABLE
 #include <linux/stackleak.h>
 #endif
-#ifdef CONFIG_LOCKUP_DETECTOR
-#include <linux/nmi.h>
-#endif
 
 #if defined(CONFIG_SYSCTL)
 
 /* Constants used for minimum and  maximum */
-#ifdef CONFIG_LOCKUP_DETECTOR
-static int sixty = 60;
-#endif
 
 static unsigned long zero_ul;
 static unsigned long one_ul = 1;
@@ -2308,96 +2302,6 @@ static struct ctl_table kern_table[] = {
 		.mode		= 0444,
 		.proc_handler	= proc_dointvec,
 	},
-#if defined(CONFIG_LOCKUP_DETECTOR)
-	{
-		.procname       = "watchdog",
-		.data		= &watchdog_user_enabled,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler   = proc_watchdog,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-	{
-		.procname	= "watchdog_thresh",
-		.data		= &watchdog_thresh,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_watchdog_thresh,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= &sixty,
-	},
-	{
-		.procname       = "nmi_watchdog",
-		.data		= &nmi_watchdog_user_enabled,
-		.maxlen		= sizeof(int),
-		.mode		= NMI_WATCHDOG_SYSCTL_PERM,
-		.proc_handler   = proc_nmi_watchdog,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-	{
-		.procname	= "watchdog_cpumask",
-		.data		= &watchdog_cpumask_bits,
-		.maxlen		= NR_CPUS,
-		.mode		= 0644,
-		.proc_handler	= proc_watchdog_cpumask,
-	},
-#ifdef CONFIG_SOFTLOCKUP_DETECTOR
-	{
-		.procname       = "soft_watchdog",
-		.data		= &soft_watchdog_user_enabled,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler   = proc_soft_watchdog,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-	{
-		.procname	= "softlockup_panic",
-		.data		= &softlockup_panic,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-#ifdef CONFIG_SMP
-	{
-		.procname	= "softlockup_all_cpu_backtrace",
-		.data		= &sysctl_softlockup_all_cpu_backtrace,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-#endif /* CONFIG_SMP */
-#endif
-#ifdef CONFIG_HARDLOCKUP_DETECTOR
-	{
-		.procname	= "hardlockup_panic",
-		.data		= &hardlockup_panic,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-#ifdef CONFIG_SMP
-	{
-		.procname	= "hardlockup_all_cpu_backtrace",
-		.data		= &sysctl_hardlockup_all_cpu_backtrace,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= SYSCTL_ZERO,
-		.extra2		= SYSCTL_ONE,
-	},
-#endif /* CONFIG_SMP */
-#endif
-#endif
-
 #if defined(CONFIG_X86_LOCAL_APIC) && defined(CONFIG_X86)
 	{
 		.procname       = "unknown_nmi_panic",
diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index ad912511a0c08..148ff8ff71307 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -740,6 +740,106 @@ int proc_watchdog_cpumask(struct ctl_table *table, int write,
 	mutex_unlock(&watchdog_mutex);
 	return err;
 }
+
+static const int sixty = 60;
+
+static struct ctl_table watchdog_sysctls[] = {
+	{
+		.procname       = "watchdog",
+		.data		= &watchdog_user_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler   = proc_watchdog,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "watchdog_thresh",
+		.data		= &watchdog_thresh,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_watchdog_thresh,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= (void *)&sixty,
+	},
+	{
+		.procname       = "nmi_watchdog",
+		.data		= &nmi_watchdog_user_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= NMI_WATCHDOG_SYSCTL_PERM,
+		.proc_handler   = proc_nmi_watchdog,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "watchdog_cpumask",
+		.data		= &watchdog_cpumask_bits,
+		.maxlen		= NR_CPUS,
+		.mode		= 0644,
+		.proc_handler	= proc_watchdog_cpumask,
+	},
+#ifdef CONFIG_SOFTLOCKUP_DETECTOR
+	{
+		.procname       = "soft_watchdog",
+		.data		= &soft_watchdog_user_enabled,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler   = proc_soft_watchdog,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+	{
+		.procname	= "softlockup_panic",
+		.data		= &softlockup_panic,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#ifdef CONFIG_SMP
+	{
+		.procname	= "softlockup_all_cpu_backtrace",
+		.data		= &sysctl_softlockup_all_cpu_backtrace,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif /* CONFIG_SMP */
+#endif
+#ifdef CONFIG_HARDLOCKUP_DETECTOR
+	{
+		.procname	= "hardlockup_panic",
+		.data		= &hardlockup_panic,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#ifdef CONFIG_SMP
+	{
+		.procname	= "hardlockup_all_cpu_backtrace",
+		.data		= &sysctl_hardlockup_all_cpu_backtrace,
+		.maxlen		= sizeof(int),
+		.mode		= 0644,
+		.proc_handler	= proc_dointvec_minmax,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
+	},
+#endif /* CONFIG_SMP */
+#endif
+	{}
+};
+
+static void __init watchdog_sysctl_init(void)
+{
+	register_sysctl_init("kernel", watchdog_sysctls, "watchdog_sysctls");
+}
+#else
+#define watchdog_sysctl_init() do { } while (0)
 #endif /* CONFIG_SYSCTL */
 
 void __init lockup_detector_init(void)
@@ -753,4 +853,5 @@ void __init lockup_detector_init(void)
 	if (!watchdog_nmi_probe())
 		nmi_watchdog_available = true;
 	lockup_detector_setup();
+	watchdog_sysctl_init();
 }