[PATCH] sysctl: remove insert_at_head from register_sysctl

The semantic effect of insert_at_head is that it would allow new registered
sysctl entries to override existing sysctl entries of the same name.  Which is
pain for caching and the proc interface never implemented.

I have done an audit and discovered that none of the current users of
register_sysctl care as (excpet for directories) they do not register
duplicate sysctl entries.

So this patch simply removes the support for overriding existing entries in
the sys_sysctl interface since no one uses it or cares and it makes future
enhancments harder.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Ralf Baechle <ralf@linux-mips.org>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Corey Minyard <minyard@acm.org>
Cc: Neil Brown <neilb@suse.de>
Cc: "John W. Linville" <linville@tuxdriver.com>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Cc: Jan Kara <jack@ucw.cz>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: David Chinner <dgc@sgi.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Patrick McHardy <kaber@trash.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/arm/kernel/isa.c

@@ -70,5 +70,5 @@ register_isa_ports(unsigned int membase, unsigned int portbase, unsigned int por
 	isa_membase = membase;
 	isa_portbase = portbase;
 	isa_portshift = portshift;
-	isa_sysctl_header = register_sysctl_table(ctl_bus, 0);
+	isa_sysctl_header = register_sysctl_table(ctl_bus);
 }

arch/frv/kernel/pm.c

@@ -455,7 +455,7 @@ static struct ctl_table pm_dir_table[] =
  */
 static int __init pm_init(void)
 {
-	register_sysctl_table(pm_dir_table, 0);
+	register_sysctl_table(pm_dir_table);
 	return 0;
 }
 

arch/frv/kernel/sysctl.c

@@ -216,7 +216,7 @@ static struct ctl_table frv_dir_table[] =
  */
 static int __init frv_sysctl_init(void)
 {
-	register_sysctl_table(frv_dir_table, 0);
+	register_sysctl_table(frv_dir_table);
 	return 0;
 }
 

arch/ia64/kernel/crash.c

@@ -222,7 +222,7 @@ machine_crash_setup(void)
 	if((ret = register_die_notifier(&kdump_init_notifier_nb)) != 0)
 		return ret;
 #ifdef CONFIG_SYSCTL
-	register_sysctl_table(sys_table, 0);
+	register_sysctl_table(sys_table);
 #endif
 	return 0;
 }

arch/ia64/kernel/perfmon.c

@@ -6726,7 +6726,7 @@ pfm_init(void)
 	/*
 	 * create /proc/sys/kernel/perfmon (for debugging purposes)
 	 */
-	pfm_sysctl_header = register_sysctl_table(pfm_sysctl_root, 0);
+	pfm_sysctl_header = register_sysctl_table(pfm_sysctl_root);
 
 	/*
 	 * initialize all our spinlocks

arch/ia64/sn/kernel/xpc_main.c

@@ -1241,7 +1241,7 @@ xpc_init(void)
 	snprintf(xpc_part->bus_id, BUS_ID_SIZE, "part");
 	snprintf(xpc_chan->bus_id, BUS_ID_SIZE, "chan");
 
-	xpc_sysctl = register_sysctl_table(xpc_sys_dir, 0);
+	xpc_sysctl = register_sysctl_table(xpc_sys_dir);
 
 	/*
 	 * The first few fields of each entry of xpc_partitions[] need to

arch/mips/au1000/common/power.c

@@ -461,7 +461,7 @@ static struct ctl_table pm_dir_table[] = {
  */
 static int __init pm_init(void)
 {
-	register_sysctl_table(pm_dir_table, 0);
+	register_sysctl_table(pm_dir_table);
 	return 0;
 }
 

arch/mips/lasat/sysctl.c

@@ -432,7 +432,7 @@ static int __init lasat_register_sysctl(void)
 	struct ctl_table_header *lasat_table_header;
 
 	lasat_table_header =
-		register_sysctl_table(lasat_root_table, 0);
+		register_sysctl_table(lasat_root_table);
 
 	return 0;
 }

arch/powerpc/kernel/idle.c

@@ -125,7 +125,7 @@ static ctl_table powersave_nap_sysctl_root[] = {
 static int __init
 register_powersave_nap_sysctl(void)
 {
-	register_sysctl_table(powersave_nap_sysctl_root, 0);
+	register_sysctl_table(powersave_nap_sysctl_root);
 
 	return 0;
 }

arch/ppc/kernel/ppc_htab.c

@@ -457,7 +457,7 @@ static ctl_table htab_sysctl_root[] = {
 static int __init
 register_ppc_htab_sysctl(void)
 {
-	register_sysctl_table(htab_sysctl_root, 0);
+	register_sysctl_table(htab_sysctl_root);
 
 	return 0;
 }

arch/s390/appldata/appldata_base.c

@@ -506,7 +506,7 @@ int appldata_register_ops(struct appldata_ops *ops)
 
 	ops->ctl_table[3].ctl_name = 0;
 
-	ops->sysctl_header = register_sysctl_table(ops->ctl_table,0);
+	ops->sysctl_header = register_sysctl_table(ops->ctl_table);
 
 	P_INFO("%s-ops registered!\n", ops->name);
 	return 0;
@@ -606,7 +606,7 @@ static int __init appldata_init(void)
 	/* Register cpu hotplug notifier */
 	register_hotcpu_notifier(&appldata_nb);
 
-	appldata_sysctl_header = register_sysctl_table(appldata_dir_table, 0);
+	appldata_sysctl_header = register_sysctl_table(appldata_dir_table);
 #ifdef MODULE
 	appldata_dir_table[0].de->owner = THIS_MODULE;
 	appldata_table[0].de->owner = THIS_MODULE;

arch/s390/kernel/debug.c

@@ -1053,7 +1053,7 @@ __init debug_init(void)
 {
 	int rc = 0;
 
-	s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table, 0);
+	s390dbf_sysctl_header = register_sysctl_table(s390dbf_dir_table);
 	down(&debug_lock);
 	debug_debugfs_root_entry = debugfs_create_dir(DEBUG_DIR_ROOT,NULL);
 	printk(KERN_INFO "debug: Initialization complete\n");

arch/s390/mm/cmm.c

@@ -418,7 +418,7 @@ cmm_init (void)
 	int rc = -ENOMEM;
 
 #ifdef CONFIG_CMM_PROC
-	cmm_sysctl_header = register_sysctl_table(cmm_dir_table, 0);
+	cmm_sysctl_header = register_sysctl_table(cmm_dir_table);
 	if (!cmm_sysctl_header)
 		goto out;
 #endif

arch/sh64/kernel/traps.c

@@ -960,7 +960,7 @@ static ctl_table sh64_root[] = {
 static struct ctl_table_header *sysctl_header;
 static int __init init_sysctl(void)
 {
-	sysctl_header = register_sysctl_table(sh64_root, 0);
+	sysctl_header = register_sysctl_table(sh64_root);
 	return 0;
 }
 

arch/x86_64/ia32/ia32_binfmt.c

@@ -367,7 +367,7 @@ static ctl_table abi_root_table2[] = {
 
 static __init int ia32_binfmt_init(void)
 { 
-	register_sysctl_table(abi_root_table2, 0);
+	register_sysctl_table(abi_root_table2);
 	return 0;
 }
 __initcall(ia32_binfmt_init);

arch/x86_64/kernel/vsyscall.c

@@ -301,7 +301,7 @@ static int __init vsyscall_init(void)
 	BUG_ON((unsigned long) &vgetcpu != VSYSCALL_ADDR(__NR_vgetcpu));
 	map_vsyscall();
 #ifdef CONFIG_SYSCTL
-	register_sysctl_table(kernel_root_table2, 0);
+	register_sysctl_table(kernel_root_table2);
 #endif
 	on_each_cpu(cpu_vsyscall_init, NULL, 0, 1);
 	hotcpu_notifier(cpu_vsyscall_notifier, 0);

arch/x86_64/mm/init.c

@@ -734,7 +734,7 @@ static ctl_table debug_root_table2[] = {
 
 static __init int x8664_sysctl_init(void)
 { 
-	register_sysctl_table(debug_root_table2, 0);
+	register_sysctl_table(debug_root_table2);
 	return 0;
 }
 __initcall(x8664_sysctl_init);

drivers/cdrom/cdrom.c

@@ -3553,7 +3553,7 @@ static void cdrom_sysctl_register(void)
 	if (initialized == 1)
 		return;
 
-	cdrom_sysctl_header = register_sysctl_table(cdrom_root_table, 0);
+	cdrom_sysctl_header = register_sysctl_table(cdrom_root_table);
 
 	/* set the defaults */
 	cdrom_sysctl_settings.autoclose = autoclose;

drivers/char/hpet.c

@@ -1018,7 +1018,7 @@ static int __init hpet_init(void)
 	if (result < 0)
 		return -ENODEV;
 
-	sysctl_header = register_sysctl_table(dev_root, 0);
+	sysctl_header = register_sysctl_table(dev_root);
 
 	result = acpi_bus_register_driver(&hpet_acpi_driver);
 	if (result < 0) {

drivers/char/ipmi/ipmi_poweroff.c

@@ -686,7 +686,7 @@ static int ipmi_poweroff_init (void)
 		printk(KERN_INFO PFX "Power cycle is enabled.\n");
 
 #ifdef CONFIG_PROC_FS
-	ipmi_table_header = register_sysctl_table(ipmi_root_table, 0);
+	ipmi_table_header = register_sysctl_table(ipmi_root_table);
 	if (!ipmi_table_header) {
 		printk(KERN_ERR PFX "Unable to register powercycle sysctl\n");
 		rv = -ENOMEM;

drivers/char/rtc.c

@@ -316,7 +316,7 @@ static struct ctl_table_header *sysctl_header;
 
 static int __init init_sysctl(void)
 {
-    sysctl_header = register_sysctl_table(dev_root, 0);
+    sysctl_header = register_sysctl_table(dev_root);
     return 0;
 }
 

drivers/macintosh/mac_hid.c

@@ -138,7 +138,7 @@ int __init mac_hid_init(void)
 		return err;
 
 #if defined(CONFIG_SYSCTL)
-	mac_hid_sysctl_header = register_sysctl_table(mac_hid_root_dir, 0);
+	mac_hid_sysctl_header = register_sysctl_table(mac_hid_root_dir);
 #endif /* CONFIG_SYSCTL */
 
 	return 0;

drivers/md/md.c

@@ -5581,7 +5581,7 @@ static int __init md_init(void)
 			    md_probe, NULL, NULL);
 
 	register_reboot_notifier(&md_notifier);
-	raid_table_header = register_sysctl_table(raid_root_table, 0);
+	raid_table_header = register_sysctl_table(raid_root_table);
 
 	md_geninit();
 	return (0);

drivers/net/wireless/arlan-proc.c

@@ -1244,7 +1244,7 @@ int __init init_arlan_proc(void)
 		return 0;
 	for (i = 0; i < MAX_ARLANS && arlan_device[i]; i++)
 		arlan_table[i].ctl_name = i + 1;
-	arlan_device_sysctl_header = register_sysctl_table(arlan_root_table, 0);
+	arlan_device_sysctl_header = register_sysctl_table(arlan_root_table);
 	if (!arlan_device_sysctl_header)
 		return -1;
 

drivers/parport/procfs.c

@@ -518,7 +518,7 @@ int parport_proc_register(struct parport *port)
 	t->parport_dir[0].child = t->port_dir;
 	t->dev_dir[0].child = t->parport_dir;
 
-	t->sysctl_header = register_sysctl_table(t->dev_dir, 0);
+	t->sysctl_header = register_sysctl_table(t->dev_dir);
 	if (t->sysctl_header == NULL) {
 		kfree(t);
 		t = NULL;
@@ -574,7 +574,7 @@ int parport_device_proc_register(struct pardevice *device)
 	t->device_dir[0].child = t->vars;
 	t->vars[0].data = &device->timeslice;
 
-	t->sysctl_header = register_sysctl_table(t->dev_dir, 0);
+	t->sysctl_header = register_sysctl_table(t->dev_dir);
 	if (t->sysctl_header == NULL) {
 		kfree(t);
 		t = NULL;
@@ -597,7 +597,7 @@ int parport_device_proc_unregister(struct pardevice *device)
 static int __init parport_default_proc_register(void)
 {
 	parport_default_sysctl_table.sysctl_header =
-		register_sysctl_table(parport_default_sysctl_table.dev_dir, 0);
+		register_sysctl_table(parport_default_sysctl_table.dev_dir);
 	return 0;
 }
 

drivers/scsi/scsi_sysctl.c

@@ -41,7 +41,7 @@ static struct ctl_table_header *scsi_table_header;
 
 int __init scsi_init_sysctl(void)
 {
-	scsi_table_header = register_sysctl_table(scsi_root_table, 0);
+	scsi_table_header = register_sysctl_table(scsi_root_table);
 	if (!scsi_table_header)
 		return -ENOMEM;
 	return 0;

fs/coda/sysctl.c

@@ -271,7 +271,7 @@ void coda_sysctl_init(void)
 
 #ifdef CONFIG_SYSCTL
 	if ( !fs_table_header )
-		fs_table_header = register_sysctl_table(fs_table, 0);
+		fs_table_header = register_sysctl_table(fs_table);
 #endif 
 }
 

fs/dquot.c

@@ -1841,7 +1841,7 @@ static int __init dquot_init(void)
 
 	printk(KERN_NOTICE "VFS: Disk quotas %s\n", __DQUOT_VERSION__);
 
-	register_sysctl_table(sys_table, 0);
+	register_sysctl_table(sys_table);
 
 	dquot_cachep = kmem_cache_create("dquot", 
 			sizeof(struct dquot), sizeof(unsigned long) * 4,

fs/lockd/svc.c

@@ -512,7 +512,7 @@ module_param(nsm_use_hostnames, bool, 0644);
 
 static int __init init_nlm(void)
 {
-	nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root, 0);
+	nlm_sysctl_table = register_sysctl_table(nlm_sysctl_root);
 	return nlm_sysctl_table ? 0 : -ENOMEM;
 }
 

fs/nfs/sysctl.c

@@ -75,7 +75,7 @@ static ctl_table nfs_cb_sysctl_root[] = {
 
 int nfs_register_sysctl(void)
 {
-	nfs_callback_sysctl_table = register_sysctl_table(nfs_cb_sysctl_root, 0);
+	nfs_callback_sysctl_table = register_sysctl_table(nfs_cb_sysctl_root);
 	if (nfs_callback_sysctl_table == NULL)
 		return -ENOMEM;
 	return 0;

fs/ntfs/sysctl.c

@@ -70,7 +70,7 @@ int ntfs_sysctl(int add)
 {
 	if (add) {
 		BUG_ON(sysctls_root_table);
-		sysctls_root_table = register_sysctl_table(sysctls_root, 0);
+		sysctls_root_table = register_sysctl_table(sysctls_root);
 		if (!sysctls_root_table)
 			return -ENOMEM;
 #ifdef CONFIG_PROC_FS

fs/ocfs2/cluster/nodemanager.c

@@ -922,7 +922,7 @@ static int __init init_o2nm(void)
 	o2hb_init();
 	o2net_init();
 
-	ocfs2_table_header = register_sysctl_table(ocfs2_root_table, 0);
+	ocfs2_table_header = register_sysctl_table(ocfs2_root_table);
 	if (!ocfs2_table_header) {
 		printk(KERN_ERR "nodemanager: unable to register sysctl\n");
 		ret = -ENOMEM; /* or something. */

fs/xfs/linux-2.6/xfs_sysctl.c

@@ -251,7 +251,7 @@ static ctl_table xfs_root_table[] = {
 void
 xfs_sysctl_register(void)
 {
-	xfs_table_header = register_sysctl_table(xfs_root_table, 0);
+	xfs_table_header = register_sysctl_table(xfs_root_table);
 }
 
 void

include/linux/sysctl.h

@@ -1035,8 +1035,8 @@ struct ctl_table_header
 	struct completion *unregistering;
 };
 
-struct ctl_table_header * register_sysctl_table(ctl_table * table, 
-						int insert_at_head);
+struct ctl_table_header * register_sysctl_table(ctl_table * table);
+
 void unregister_sysctl_table(struct ctl_table_header * table);
 
 #else /* __KERNEL__ */

ipc/ipc_sysctl.c

@@ -176,7 +176,7 @@ static struct ctl_table ipc_root_table[] = {
 
 static int __init ipc_sysctl_init(void)
 {
-	register_sysctl_table(ipc_root_table, 0);
+	register_sysctl_table(ipc_root_table);
 	return 0;
 }
 

ipc/mqueue.c

@@ -1255,7 +1255,7 @@ static int __init init_mqueue_fs(void)
 		return -ENOMEM;
 
 	/* ignore failues - they are not fatal */
-	mq_sysctl_table = register_sysctl_table(mq_sysctl_root, 0);
+	mq_sysctl_table = register_sysctl_table(mq_sysctl_root);
 
 	error = register_filesystem(&mqueue_fs_type);
 	if (error)

kernel/sysctl.c

@@ -1244,7 +1244,6 @@ int do_sysctl_strategy (ctl_table *table,
 /**
  * register_sysctl_table - register a sysctl hierarchy
  * @table: the top-level table structure
- * @insert_at_head: whether the entry should be inserted in front or at the end
  *
  * Register a sysctl table hierarchy. @table should be a filled in ctl_table
  * array. An entry with a ctl_name of 0 terminates the table. 
@@ -1310,8 +1309,7 @@ int do_sysctl_strategy (ctl_table *table,
  * This routine returns %NULL on a failure to register, and a pointer
  * to the table header on success.
  */
-struct ctl_table_header *register_sysctl_table(ctl_table * table, 
-					       int insert_at_head)
+struct ctl_table_header *register_sysctl_table(ctl_table * table)
 {
 	struct ctl_table_header *tmp;
 	tmp = kmalloc(sizeof(struct ctl_table_header), GFP_KERNEL);
@@ -1322,10 +1320,7 @@ struct ctl_table_header *register_sysctl_table(ctl_table * table,
 	tmp->used = 0;
 	tmp->unregistering = NULL;
 	spin_lock(&sysctl_lock);
-	if (insert_at_head)
-		list_add(&tmp->ctl_entry, &root_table_header.ctl_entry);
-	else
-		list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
+	list_add_tail(&tmp->ctl_entry, &root_table_header.ctl_entry);
 	spin_unlock(&sysctl_lock);
 #ifdef CONFIG_PROC_SYSCTL
 	register_proc_table(table, proc_sys_root, tmp);

kernel/utsname_sysctl.c

@@ -139,7 +139,7 @@ static struct ctl_table uts_root_table[] = {
 
 static int __init utsname_sysctl_init(void)
 {
-	register_sysctl_table(uts_root_table, 0);
+	register_sysctl_table(uts_root_table);
 	return 0;
 }
 

net/appletalk/sysctl_net_atalk.c

@@ -73,7 +73,7 @@ static struct ctl_table_header *atalk_table_header;
 
 void atalk_register_sysctl(void)
 {
-	atalk_table_header = register_sysctl_table(atalk_root_table, 0);
+	atalk_table_header = register_sysctl_table(atalk_root_table);
 }
 
 void atalk_unregister_sysctl(void)