watchdog/core: remove sysctl handlers from public header

The functions are only used in the file where they are defined.  Remove
them from the header and make them static.

Also guard proc_soft_watchdog with a #define-guard as it is not used
otherwise.

Link: https://lkml.kernel.org/r/20240306-const-sysctl-prep-watchdog-v1-1-bd45da3a41cf@weissschuh.netSigned-off-by: Thomas Weißschuh <linux@weissschuh.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

include/linux/nmi.h

@@ -216,13 +216,6 @@ void watchdog_update_hrtimer_threshold(u64 period);
 static inline void watchdog_update_hrtimer_threshold(u64 period) { }
 #endif
 
-struct ctl_table;
-int proc_watchdog(struct ctl_table *, int, void *, size_t *, loff_t *);
-int proc_nmi_watchdog(struct ctl_table *, int , void *, size_t *, loff_t *);
-int proc_soft_watchdog(struct ctl_table *, int , void *, size_t *, loff_t *);
-int proc_watchdog_thresh(struct ctl_table *, int , void *, size_t *, loff_t *);
-int proc_watchdog_cpumask(struct ctl_table *, int, void *, size_t *, loff_t *);
-
 #ifdef CONFIG_HAVE_ACPI_APEI_NMI
 #include <asm/nmi.h>
 #endif

kernel/watchdog.c

@@ -796,7 +796,7 @@ static int proc_watchdog_common(int which, struct ctl_table *table, int write,
 /*
  * /proc/sys/kernel/watchdog
  */
-int proc_watchdog(struct ctl_table *table, int write,
+static int proc_watchdog(struct ctl_table *table, int write,
 			 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return proc_watchdog_common(WATCHDOG_HARDLOCKUP_ENABLED |
@@ -807,7 +807,7 @@ int proc_watchdog(struct ctl_table *table, int write,
 /*
  * /proc/sys/kernel/nmi_watchdog
  */
-int proc_nmi_watchdog(struct ctl_table *table, int write,
+static int proc_nmi_watchdog(struct ctl_table *table, int write,
 			     void *buffer, size_t *lenp, loff_t *ppos)
 {
 	if (!watchdog_hardlockup_available && write)
@@ -816,20 +816,22 @@ int proc_nmi_watchdog(struct ctl_table *table, int write,
 				    table, write, buffer, lenp, ppos);
 }
 
+#ifdef CONFIG_SOFTLOCKUP_DETECTOR
 /*
  * /proc/sys/kernel/soft_watchdog
  */
-int proc_soft_watchdog(struct ctl_table *table, int write,
+static int proc_soft_watchdog(struct ctl_table *table, int write,
 			      void *buffer, size_t *lenp, loff_t *ppos)
 {
 	return proc_watchdog_common(WATCHDOG_SOFTOCKUP_ENABLED,
 				    table, write, buffer, lenp, ppos);
 }
+#endif
 
 /*
  * /proc/sys/kernel/watchdog_thresh
  */
-int proc_watchdog_thresh(struct ctl_table *table, int write,
+static int proc_watchdog_thresh(struct ctl_table *table, int write,
 				void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int err, old;
@@ -852,7 +854,7 @@ int proc_watchdog_thresh(struct ctl_table *table, int write,
  * user to specify a mask that will include cpus that have not yet
  * been brought online, if desired.
  */
-int proc_watchdog_cpumask(struct ctl_table *table, int write,
+static int proc_watchdog_cpumask(struct ctl_table *table, int write,
 				 void *buffer, size_t *lenp, loff_t *ppos)
 {
 	int err;