sysctl: remove all extern declaration from sysctl.c

Extern declarations in .c files are a bad style and can lead to
mismatches.  Use existing definitions in headers where they exist,
and otherwise move the external declarations to suitable header
files.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

include/linux/coredump.h

@@ -22,4 +22,8 @@ extern void do_coredump(const kernel_siginfo_t *siginfo);
 static inline void do_coredump(const kernel_siginfo_t *siginfo) {}
 #endif
 
+extern int core_uses_pid;
+extern char core_pattern[];
+extern unsigned int core_pipe_limit;
+
 #endif /* _LINUX_COREDUMP_H */

include/linux/file.h

@@ -94,4 +94,6 @@ extern void fd_install(unsigned int fd, struct file *file);
 extern void flush_delayed_fput(void);
 extern void __fput_sync(struct file *);
 
+extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
+
 #endif /* __LINUX_FILE_H */

include/linux/mm.h

@@ -3140,5 +3140,7 @@ unsigned long wp_shared_mapping_range(struct address_space *mapping,
 				      pgoff_t first_index, pgoff_t nr);
 #endif
 
+extern int sysctl_nr_trim_pages;
+
 #endif /* __KERNEL__ */
 #endif /* _LINUX_MM_H */

include/linux/mmzone.h

@@ -909,6 +909,7 @@ static inline int is_highmem(struct zone *zone)
 
 /* These two functions are used to setup the per zone pages min values */
 struct ctl_table;
+
 int min_free_kbytes_sysctl_handler(struct ctl_table *, int,
 					void __user *, size_t *, loff_t *);
 int watermark_scale_factor_sysctl_handler(struct ctl_table *, int,
@@ -925,6 +926,7 @@ int sysctl_min_slab_ratio_sysctl_handler(struct ctl_table *, int,
 
 extern int numa_zonelist_order_handler(struct ctl_table *, int,
 			void __user *, size_t *, loff_t *);
+extern int percpu_pagelist_fraction;
 extern char numa_zonelist_order[];
 #define NUMA_ZONELIST_ORDER_LEN	16
 

include/linux/pid.h

@@ -108,6 +108,9 @@ extern void transfer_pid(struct task_struct *old, struct task_struct *new,
 struct pid_namespace;
 extern struct pid_namespace init_pid_ns;
 
+extern int pid_max;
+extern int pid_max_min, pid_max_max;
+
 /*
  * look up a PID in the hash table. Must be called with the tasklist_lock
  * or rcu_read_lock() held.

include/linux/sysctl.h

@@ -207,7 +207,15 @@ void unregister_sysctl_table(struct ctl_table_header * table);
 
 extern int sysctl_init(void);
 
+extern int pwrsw_enabled;
+extern int unaligned_enabled;
+extern int unaligned_dump_stack;
+extern int no_unaligned_warning;
+
 extern struct ctl_table sysctl_mount_point[];
+extern struct ctl_table random_table[];
+extern struct ctl_table firmware_config_table[];
+extern struct ctl_table epoll_table[];
 
 #else /* CONFIG_SYSCTL */
 static inline struct ctl_table_header *register_sysctl_table(struct ctl_table * table)

kernel/sysctl.c

@@ -68,6 +68,9 @@
 #include <linux/bpf.h>
 #include <linux/mount.h>
 #include <linux/userfaultfd_k.h>
+#include <linux/coredump.h>
+#include <linux/latencytop.h>
+#include <linux/pid.h>
 
 #include "../lib/kstrtox.h"
 
@@ -103,22 +106,6 @@
 
 #if defined(CONFIG_SYSCTL)
 
-/* External variables not in a header file. */
-extern int suid_dumpable;
-#ifdef CONFIG_COREDUMP
-extern int core_uses_pid;
-extern char core_pattern[];
-extern unsigned int core_pipe_limit;
-#endif
-extern int pid_max;
-extern int pid_max_min, pid_max_max;
-extern int percpu_pagelist_fraction;
-extern int latencytop_enabled;
-extern unsigned int sysctl_nr_open_min, sysctl_nr_open_max;
-#ifndef CONFIG_MMU
-extern int sysctl_nr_trim_pages;
-#endif
-
 /* Constants used for minimum and  maximum */
 #ifdef CONFIG_LOCKUP_DETECTOR
 static int sixty = 60;
@@ -160,24 +147,6 @@ static unsigned long hung_task_timeout_max = (LONG_MAX/HZ);
 #ifdef CONFIG_INOTIFY_USER
 #include <linux/inotify.h>
 #endif
-#ifdef CONFIG_SPARC
-#endif
-
-#ifdef CONFIG_PARISC
-extern int pwrsw_enabled;
-#endif
-
-#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_ALLOW
-extern int unaligned_enabled;
-#endif
-
-#ifdef CONFIG_IA64
-extern int unaligned_dump_stack;
-#endif
-
-#ifdef CONFIG_SYSCTL_ARCH_UNALIGN_NO_WARN
-extern int no_unaligned_warning;
-#endif
 
 #ifdef CONFIG_PROC_SYSCTL
 
@@ -243,14 +212,6 @@ static struct ctl_table vm_table[];
 static struct ctl_table fs_table[];
 static struct ctl_table debug_table[];
 static struct ctl_table dev_table[];
-extern struct ctl_table random_table[];
-#ifdef CONFIG_EPOLL
-extern struct ctl_table epoll_table[];
-#endif
-
-#ifdef CONFIG_FW_LOADER_USER_HELPER
-extern struct ctl_table firmware_config_table[];
-#endif
 
 #if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
     defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)