proc/sysctl: add shared variables for range check

In the sysctl code the proc_dointvec_minmax() function is often used to
validate the user supplied value between an allowed range.  This
function uses the extra1 and extra2 members from struct ctl_table as
minimum and maximum allowed value.

On sysctl handler declaration, in every source file there are some
readonly variables containing just an integer which address is assigned
to the extra1 and extra2 members, so the sysctl range is enforced.

The special values 0, 1 and INT_MAX are very often used as range
boundary, leading duplication of variables like zero=0, one=1,
int_max=INT_MAX in different source files:

    $ git grep -E '\.extra[12].*&(zero|one|int_max)' |wc -l
    248

Add a const int array containing the most commonly used values, some
macros to refer more easily to the correct array member, and use them
instead of creating a local one for every object file.

This is the bloat-o-meter output comparing the old and new binary
compiled with the default Fedora config:

    # scripts/bloat-o-meter -d vmlinux.o.old vmlinux.o
    add/remove: 2/2 grow/shrink: 0/2 up/down: 24/-188 (-164)
    Data                                         old     new   delta
    sysctl_vals                                    -      12     +12
    __kstrtab_sysctl_vals                          -      12     +12
    max                                           14      10      -4
    int_max                                       16       -     -16
    one                                           68       -     -68
    zero                                         128      28    -100
    Total: Before=20583249, After=20583085, chg -0.00%

[mcroce@redhat.com: tipc: remove two unused variables]
  Link: http://lkml.kernel.org/r/20190530091952.4108-1-mcroce@redhat.com
[akpm@linux-foundation.org: fix net/ipv6/sysctl_net_ipv6.c]
[arnd@arndb.de: proc/sysctl: make firmware loader table conditional]
  Link: http://lkml.kernel.org/r/20190617130014.1713870-1-arnd@arndb.de
[akpm@linux-foundation.org: fix fs/eventpoll.c]
Link: http://lkml.kernel.org/r/20190430180111.10688-1-mcroce@redhat.com
Signed-off-by: Matteo Croce <mcroce@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Aaron Tomlin <atomlin@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

13 files changed, 97 insertions, 122 deletions

diff --git a/net/core/neighbour.c b/net/core/neighbour.c
index 742cea4ce72e..26da97359d5b 100644
--- a/net/core/neighbour.c
+++ b/net/core/neighbour.c
@@ -3374,8 +3374,6 @@ void neigh_app_ns(struct neighbour *n)
 EXPORT_SYMBOL(neigh_app_ns);
 
 #ifdef CONFIG_SYSCTL
-static int zero;
-static int int_max = INT_MAX;
 static int unres_qlen_max = INT_MAX / SKB_TRUESIZE(ETH_FRAME_LEN);
 
 static int proc_unres_qlen(struct ctl_table *ctl, int write,
@@ -3384,7 +3382,7 @@ static int proc_unres_qlen(struct ctl_table *ctl, int write,
 	int size, ret;
 	struct ctl_table tmp = *ctl;
 
-	tmp.extra1 = &zero;
+	tmp.extra1 = SYSCTL_ZERO;
 	tmp.extra2 = &unres_qlen_max;
 	tmp.data = &size;
 
@@ -3449,8 +3447,8 @@ static int neigh_proc_dointvec_zero_intmax(struct ctl_table *ctl, int write,
 	struct ctl_table tmp = *ctl;
 	int ret;
 
-	tmp.extra1 = &zero;
-	tmp.extra2 = &int_max;
+	tmp.extra1 = SYSCTL_ZERO;
+	tmp.extra2 = SYSCTL_INT_MAX;
 
 	ret = proc_dointvec_minmax(&tmp, write, buffer, lenp, ppos);
 	neigh_proc_update(ctl, write);
@@ -3595,24 +3593,24 @@ static struct neigh_sysctl_table {
 			.procname	= "gc_thresh1",
 			.maxlen		= sizeof(int),
 			.mode		= 0644,
-			.extra1 	= &zero,
-			.extra2		= &int_max,
+			.extra1		= SYSCTL_ZERO,
+			.extra2		= SYSCTL_INT_MAX,
 			.proc_handler	= proc_dointvec_minmax,
 		},
 		[NEIGH_VAR_GC_THRESH2] = {
 			.procname	= "gc_thresh2",
 			.maxlen		= sizeof(int),
 			.mode		= 0644,
-			.extra1 	= &zero,
-			.extra2		= &int_max,
+			.extra1		= SYSCTL_ZERO,
+			.extra2		= SYSCTL_INT_MAX,
 			.proc_handler	= proc_dointvec_minmax,
 		},
 		[NEIGH_VAR_GC_THRESH3] = {
 			.procname	= "gc_thresh3",
 			.maxlen		= sizeof(int),
 			.mode		= 0644,
-			.extra1 	= &zero,
-			.extra2		= &int_max,
+			.extra1		= SYSCTL_ZERO,
+			.extra2		= SYSCTL_INT_MAX,
 			.proc_handler	= proc_dointvec_minmax,
 		},
 		{},
diff --git a/net/core/sysctl_net_core.c b/net/core/sysctl_net_core.c
index f9204719aeee..8da5b3a54dac 100644
--- a/net/core/sysctl_net_core.c
+++ b/net/core/sysctl_net_core.c
@@ -22,8 +22,6 @@
 #include <net/busy_poll.h>
 #include <net/pkt_sched.h>
 
-static int zero = 0;
-static int one = 1;
 static int two __maybe_unused = 2;
 static int min_sndbuf = SOCK_MIN_SNDBUF;
 static int min_rcvbuf = SOCK_MIN_RCVBUF;
@@ -390,10 +388,10 @@ static struct ctl_table net_core_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax_bpf_enable,
 # ifdef CONFIG_BPF_JIT_ALWAYS_ON
-		.extra1		= &one,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_ONE,
 # else
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &two,
 # endif
 	},
@@ -404,7 +402,7 @@ static struct ctl_table net_core_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0600,
 		.proc_handler	= proc_dointvec_minmax_bpf_restricted,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &two,
 	},
 	{
@@ -413,8 +411,8 @@ static struct ctl_table net_core_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0600,
 		.proc_handler	= proc_dointvec_minmax_bpf_restricted,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 # endif
 	{
@@ -461,8 +459,8 @@ static struct ctl_table net_core_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE
 	},
 #ifdef CONFIG_RPS
 	{
@@ -493,7 +491,7 @@ static struct ctl_table net_core_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "busy_read",
@@ -501,7 +499,7 @@ static struct ctl_table net_core_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 #endif
 #ifdef CONFIG_NET_SCHED
@@ -533,7 +531,7 @@ static struct ctl_table net_core_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 		.extra2		= &max_skb_frags,
 	},
 	{
@@ -542,7 +540,7 @@ static struct ctl_table net_core_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "fb_tunnels_only_for_init_net",
@@ -550,8 +548,8 @@ static struct ctl_table net_core_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "devconf_inherit_init_net",
@@ -559,7 +557,7 @@ static struct ctl_table net_core_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &two,
 	},
 	{
@@ -578,7 +576,7 @@ static struct ctl_table netns_core_table[] = {
 		.data		= &init_net.core.sysctl_somaxconn,
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.proc_handler	= proc_dointvec_minmax
 	},
 	{ }
diff --git a/net/dccp/sysctl.c b/net/dccp/sysctl.c
index b59040f268a9..ee8d4f5afa72 100644
--- a/net/dccp/sysctl.c
+++ b/net/dccp/sysctl.c
@@ -16,9 +16,7 @@
 #endif
 
 /* Boundary values */
-static int		zero     = 0,
-			one      = 1,
-			u8_max   = 0xFF;
+static int		u8_max   = 0xFF;
 static unsigned long	seqw_min = DCCPF_SEQ_WMIN,
 			seqw_max = 0xFFFFFFFF;		/* maximum on 32 bit */
 
@@ -38,7 +36,7 @@ static struct ctl_table dccp_default_table[] = {
 		.maxlen		= sizeof(sysctl_dccp_rx_ccid),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &u8_max,		/* RFC 4340, 10. */
 	},
 	{
@@ -47,7 +45,7 @@ static struct ctl_table dccp_default_table[] = {
 		.maxlen		= sizeof(sysctl_dccp_tx_ccid),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &u8_max,		/* RFC 4340, 10. */
 	},
 	{
@@ -56,7 +54,7 @@ static struct ctl_table dccp_default_table[] = {
 		.maxlen		= sizeof(sysctl_dccp_request_retries),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 		.extra2		= &u8_max,
 	},
 	{
@@ -65,7 +63,7 @@ static struct ctl_table dccp_default_table[] = {
 		.maxlen		= sizeof(sysctl_dccp_retries1),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &u8_max,
 	},
 	{
@@ -74,7 +72,7 @@ static struct ctl_table dccp_default_table[] = {
 		.maxlen		= sizeof(sysctl_dccp_retries2),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &u8_max,
 	},
 	{
@@ -83,7 +81,7 @@ static struct ctl_table dccp_default_table[] = {
 		.maxlen		= sizeof(sysctl_dccp_tx_qlen),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "sync_ratelimit",
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 7d66306b5f39..0b980e841927 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -28,8 +28,6 @@
 #include <net/protocol.h>
 #include <net/netevent.h>
 
-static int zero;
-static int one = 1;
 static int two = 2;
 static int four = 4;
 static int thousand = 1000;
@@ -576,7 +574,7 @@ static struct ctl_table ipv4_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "icmp_msgs_burst",
@@ -584,7 +582,7 @@ static struct ctl_table ipv4_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 	{
 		.procname	= "udp_mem",
@@ -674,8 +672,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 	{
@@ -763,8 +761,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler   = ipv4_fwd_update_priority,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "ip_nonlocal_bind",
@@ -794,8 +792,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 	{
@@ -864,7 +862,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one
+		.extra1		= SYSCTL_ONE
 	},
 #endif
 	{
@@ -969,7 +967,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &two,
 	},
 	{
@@ -1011,7 +1009,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_tfo_blackhole_detect_timeout,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 	},
 #ifdef CONFIG_IP_ROUTE_MULTIPATH
 	{
@@ -1020,8 +1018,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "fib_multipath_hash_policy",
@@ -1029,8 +1027,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_fib_multipath_hash_policy,
-		.extra1		= &zero,
-		.extra2		= &two,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 	{
@@ -1047,8 +1045,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 #endif
 	{
@@ -1078,7 +1076,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &four,
 	},
 	{
@@ -1222,7 +1220,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 		.extra2		= &gso_max_segs,
 	},
 	{
@@ -1231,7 +1229,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &one_day_secs
 	},
 	{
@@ -1240,8 +1238,8 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "tcp_invalid_ratelimit",
@@ -1256,7 +1254,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &thousand,
 	},
 	{
@@ -1265,7 +1263,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &thousand,
 	},
 	{
@@ -1274,7 +1272,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(init_net.ipv4.sysctl_tcp_wmem),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "tcp_rmem",
@@ -1282,7 +1280,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(init_net.ipv4.sysctl_tcp_rmem),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "tcp_comp_sack_delay_ns",
@@ -1297,7 +1295,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &comp_sack_nr_max,
 	},
 	{
@@ -1306,7 +1304,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(init_net.ipv4.sysctl_udp_rmem_min),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one
+		.extra1		= SYSCTL_ONE
 	},
 	{
 		.procname	= "udp_wmem_min",
@@ -1314,7 +1312,7 @@ static struct ctl_table ipv4_net_table[] = {
 		.maxlen		= sizeof(init_net.ipv4.sysctl_udp_wmem_min),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one
+		.extra1		= SYSCTL_ONE
 	},
 	{ }
 };
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 521e3203e83a..dc73888c7859 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -6432,8 +6432,6 @@ int addrconf_sysctl_disable_policy(struct ctl_table *ctl, int write,
 }
 
 static int minus_one = -1;
-static const int zero = 0;
-static const int one = 1;
 static const int two_five_five = 255;
 
 static const struct ctl_table addrconf_sysctl[] = {
@@ -6450,7 +6448,7 @@ static const struct ctl_table addrconf_sysctl[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= (void *)&one,
+		.extra1		= (void *)SYSCTL_ONE,
 		.extra2		= (void *)&two_five_five,
 	},
 	{
@@ -6809,7 +6807,7 @@ static const struct ctl_table addrconf_sysctl[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= (void *)&zero,
+		.extra1		= (void *)SYSCTL_ZERO,
 		.extra2		= (void *)&two_five_five,
 	},
 	{
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 4d2e6b31a8d6..8b0c33fb19a2 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -6031,9 +6031,6 @@ int ipv6_sysctl_rtcache_flush(struct ctl_table *ctl, int write,
 	return 0;
 }
 
-static int zero;
-static int one = 1;
-
 static struct ctl_table ipv6_route_table_template[] = {
 	{
 		.procname	=	"flush",
@@ -6111,8 +6108,8 @@ static struct ctl_table ipv6_route_table_template[] = {
 		.maxlen		=	sizeof(int),
 		.mode		=	0644,
 		.proc_handler	=	proc_dointvec_minmax,
-		.extra1		=	&zero,
-		.extra2		=	&one,
+		.extra1		=	SYSCTL_ZERO,
+		.extra2		=	SYSCTL_ONE,
 	},
 	{ }
 };
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index dc4c91e0bfb8..ec8fcfc60a27 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -21,8 +21,6 @@
 #include <net/calipso.h>
 #endif
 
-static int zero;
-static int one = 1;
 static int flowlabel_reflect_max = 0x7;
 static int auto_flowlabels_min;
 static int auto_flowlabels_max = IP6_AUTO_FLOW_LABEL_MAX;
@@ -115,7 +113,7 @@ static struct ctl_table ipv6_table_template[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &flowlabel_reflect_max,
 	},
 	{
@@ -152,8 +150,8 @@ static struct ctl_table ipv6_table_template[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler   = proc_rt6_multipath_hash_policy,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "seg6_flowlabel",
@@ -179,7 +177,7 @@ static struct ctl_table ipv6_rotable[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one
+		.extra1		= SYSCTL_ONE
 	},
 #ifdef CONFIG_NETLABEL
 	{
diff --git a/net/mpls/af_mpls.c b/net/mpls/af_mpls.c
index 198ec4fe4148..c312741df2ce 100644
--- a/net/mpls/af_mpls.c
+++ b/net/mpls/af_mpls.c
@@ -37,8 +37,6 @@
 
 #define MPLS_NEIGH_TABLE_UNSPEC (NEIGH_LINK_TABLE + 1)
 
-static int zero = 0;
-static int one = 1;
 static int label_limit = (1 << 20) - 1;
 static int ttl_max = 255;
 
@@ -2607,7 +2605,7 @@ static int mpls_platform_labels(struct ctl_table *table, int write,
 		.data		= &platform_labels,
 		.maxlen		= sizeof(int),
 		.mode		= table->mode,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &label_limit,
 	};
 
@@ -2636,8 +2634,8 @@ static const struct ctl_table mpls_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_ONE,
 	},
 	{
 		.procname	= "default_ttl",
@@ -2645,7 +2643,7 @@ static const struct ctl_table mpls_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 		.extra2		= &ttl_max,
 	},
 	{ }
diff --git a/net/netfilter/ipvs/ip_vs_ctl.c b/net/netfilter/ipvs/ip_vs_ctl.c
index 07e0967bf129..060565e7d227 100644
--- a/net/netfilter/ipvs/ip_vs_ctl.c
+++ b/net/netfilter/ipvs/ip_vs_ctl.c
@@ -1726,7 +1726,6 @@ static int ip_vs_zero_all(struct netns_ipvs *ipvs)
 
 #ifdef CONFIG_SYSCTL
 
-static int zero;
 static int three = 3;
 
 static int
@@ -1935,7 +1934,7 @@ static struct ctl_table vs_vars[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &three,
 	},
 	{
diff --git a/net/rxrpc/sysctl.c b/net/rxrpc/sysctl.c
index 1e3fa67d91aa..2bbb38161851 100644
--- a/net/rxrpc/sysctl.c
+++ b/net/rxrpc/sysctl.c
@@ -11,7 +11,6 @@
 #include "ar-internal.h"
 
 static struct ctl_table_header *rxrpc_sysctl_reg_table;
-static const unsigned int one = 1;
 static const unsigned int four = 4;
 static const unsigned int thirtytwo = 32;
 static const unsigned int n_65535 = 65535;
@@ -97,7 +96,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= (void *)&one,
+		.extra1		= (void *)SYSCTL_ONE,
 		.extra2		= (void *)&rxrpc_max_client_connections,
 	},
 	{
@@ -115,7 +114,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= (void *)&one,
+		.extra1		= (void *)SYSCTL_ONE,
 		.extra2		= (void *)&n_max_acks,
 	},
 	{
@@ -124,7 +123,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= (void *)&one,
+		.extra1		= (void *)SYSCTL_ONE,
 		.extra2		= (void *)&n_65535,
 	},
 	{
@@ -133,7 +132,7 @@ static struct ctl_table rxrpc_sysctl_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= (void *)&one,
+		.extra1		= (void *)SYSCTL_ONE,
 		.extra2		= (void *)&four,
 	},
 
diff --git a/net/sctp/sysctl.c b/net/sctp/sysctl.c
index 9a19147902f1..1250751bca1b 100644
--- a/net/sctp/sysctl.c
+++ b/net/sctp/sysctl.c
@@ -25,10 +25,7 @@
 #include <net/sctp/sctp.h>
 #include <linux/sysctl.h>
 
-static int zero = 0;
-static int one = 1;
 static int timer_max = 86400000; /* ms in one day */
-static int int_max = INT_MAX;
 static int sack_timer_min = 1;
 static int sack_timer_max = 500;
 static int addr_scope_max = SCTP_SCOPE_POLICY_MAX;
@@ -92,7 +89,7 @@ static struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1         = &one,
+		.extra1         = SYSCTL_ONE,
 		.extra2         = &timer_max
 	},
 	{
@@ -101,7 +98,7 @@ static struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_sctp_do_rto_min,
-		.extra1         = &one,
+		.extra1         = SYSCTL_ONE,
 		.extra2         = &init_net.sctp.rto_max
 	},
 	{
@@ -137,8 +134,8 @@ static struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &int_max
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_INT_MAX,
 	},
 	{
 		.procname	= "cookie_preserve_enable",
@@ -160,7 +157,7 @@ static struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1         = &one,
+		.extra1         = SYSCTL_ONE,
 		.extra2         = &timer_max
 	},
 	{
@@ -178,7 +175,7 @@ static struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1         = &one,
+		.extra1         = SYSCTL_ONE,
 		.extra2         = &timer_max
 	},
 	{
@@ -187,8 +184,8 @@ static struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
-		.extra2		= &int_max
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_INT_MAX,
 	},
 	{
 		.procname	= "path_max_retrans",
@@ -196,8 +193,8 @@ static struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
-		.extra2		= &int_max
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_INT_MAX,
 	},
 	{
 		.procname	= "max_init_retransmits",
@@ -205,8 +202,8 @@ static struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &one,
-		.extra2		= &int_max
+		.extra1		= SYSCTL_ONE,
+		.extra2		= SYSCTL_INT_MAX,
 	},
 	{
 		.procname	= "pf_retrans",
@@ -214,8 +211,8 @@ static struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &int_max
+		.extra1		= SYSCTL_ZERO,
+		.extra2		= SYSCTL_INT_MAX,
 	},
 	{
 		.procname	= "sndbuf_policy",
@@ -286,7 +283,7 @@ static struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &addr_scope_max,
 	},
 	{
@@ -295,7 +292,7 @@ static struct ctl_table sctp_net_table[] = {
 		.maxlen		= sizeof(int),
 		.mode		= 0644,
 		.proc_handler	= &proc_dointvec_minmax,
-		.extra1		= &one,
+		.extra1		= SYSCTL_ONE,
 		.extra2		= &rwnd_scale_max,
 	},
 	{
diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c
index 1f73a6a7e43c..ffb1684c4573 100644
--- a/net/sunrpc/xprtrdma/transport.c
+++ b/net/sunrpc/xprtrdma/transport.c
@@ -80,7 +80,6 @@ static unsigned int min_slot_table_size = RPCRDMA_MIN_SLOT_TABLE;
 static unsigned int max_slot_table_size = RPCRDMA_MAX_SLOT_TABLE;
 static unsigned int min_inline_size = RPCRDMA_MIN_INLINE;
 static unsigned int max_inline_size = RPCRDMA_MAX_INLINE;
-static unsigned int zero;
 static unsigned int max_padding = PAGE_SIZE;
 static unsigned int min_memreg = RPCRDMA_BOUNCEBUFFERS;
 static unsigned int max_memreg = RPCRDMA_LAST - 1;
@@ -122,7 +121,7 @@ static struct ctl_table xr_tunables_table[] = {
 		.maxlen		= sizeof(unsigned int),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1		= &zero,
+		.extra1		= SYSCTL_ZERO,
 		.extra2		= &max_padding,
 	},
 	{
diff --git a/net/tipc/sysctl.c b/net/tipc/sysctl.c
index 9df82a573aa7..6159d327db76 100644
--- a/net/tipc/sysctl.c
+++ b/net/tipc/sysctl.c
@@ -38,8 +38,6 @@
 
 #include <linux/sysctl.h>
 
-static int zero;
-static int one = 1;
 static struct ctl_table_header *tipc_ctl_hdr;
 
 static struct ctl_table tipc_table[] = {
@@ -49,7 +47,7 @@ static struct ctl_table tipc_table[] = {
 		.maxlen		= sizeof(sysctl_tipc_rmem),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1         = &one,
+		.extra1         = SYSCTL_ONE,
 	},
 	{
 		.procname	= "named_timeout",
@@ -57,7 +55,7 @@ static struct ctl_table tipc_table[] = {
 		.maxlen		= sizeof(sysctl_tipc_named_timeout),
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
-		.extra1         = &zero,
+		.extra1         = SYSCTL_ZERO,
 	},
 	{
 		.procname       = "sk_filter",