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[PATCH v5 2/8] net: ipv{6,4}: Remove the now superfluous sentinel elemen

To: "David S. Miller" <davem@xxxxxxxxxxxxx>, Eric Dumazet <edumazet@xxxxxxxxxx>, Jakub Kicinski <kuba@xxxxxxxxxx>, Paolo Abeni <pabeni@xxxxxxxxxx>, Alexander Aring <alex.aring@xxxxxxxxx>, Stefan Schmidt <stefan@xxxxxxxxxxxxxxxxxx>, Miquel Raynal <miquel.raynal@xxxxxxxxxxx>, David Ahern <dsahern@xxxxxxxxxx>, Steffen Klassert <steffen.klassert@xxxxxxxxxxx>, Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx>, Matthieu Baerts <matttbe@xxxxxxxxxx>, Mat Martineau <martineau@xxxxxxxxxx>, Geliang Tang <geliang@xxxxxxxxxx>, Ralf Baechle <ralf@xxxxxxxxxxxxxx>, Remi Denis-Courmont <courmisch@xxxxxxxxx>, Allison Henderson <allison.henderson@xxxxxxxxxx>, David Howells <dhowells@xxxxxxxxxx>, Marc Dionne <marc.dionne@xxxxxxxxxxxx>, Marcelo Ricardo Leitner <marcelo.leitner@xxxxxxxxx>, Xin Long <lucien.xin@xxxxxxxxx>, Wenjia Zhang <wenjia@xxxxxxxxxxxxx>, Jan Karcher <jaka@xxxxxxxxxxxxx>, "D. Wythe" <alibuda@xxxxxxxxxxxxxxxxx>, Tony Lu <tonylu@xxxxxxxxxxxxxxxxx>, Wen Gu <guwen@xxxxxxxxxxxxxxxxx>, Trond Myklebust <trond.myklebust@xxxxxxxxxxxxxxx>, Anna Schumaker <anna@xxxxxxxxxx>, Chuck Lever <chuck.lever@xxxxxxxxxx>, Jeff Layton <jlayton@xxxxxxxxxx>, Neil Brown <neilb@xxxxxxx>, Olga Kornievskaia <kolga@xxxxxxxxxx>, Dai Ngo <Dai.Ngo@xxxxxxxxxx>, Tom Talpey <tom@xxxxxxxxxx>, Jon Maloy <jmaloy@xxxxxxxxxx>, Ying Xue <ying.xue@xxxxxxxxxxxxx>, Martin Schiller <ms@xxxxxxxxxx>, Pablo Neira Ayuso <pablo@xxxxxxxxxxxxx>, Jozsef Kadlecsik <kadlec@xxxxxxxxxxxxx>, Florian Westphal <fw@xxxxxxxxx>, Roopa Prabhu <roopa@xxxxxxxxxx>, Nikolay Aleksandrov <razor@xxxxxxxxxxxxx>, Simon Horman <horms@xxxxxxxxxxxx>, Julian Anastasov <ja@xxxxxx>, Joerg Reuter <jreuter@xxxxxxxx>, Luis Chamberlain <mcgrof@xxxxxxxxxx>, Kees Cook <keescook@xxxxxxxxxxxx>
Subject: [PATCH v5 2/8] net: ipv{6,4}: Remove the now superfluous sentinel elements from ctl_table array
Cc: netdev@xxxxxxxxxxxxxxx, linux-kernel@xxxxxxxxxxxxxxx, dccp@xxxxxxxxxxxxxxx, linux-wpan@xxxxxxxxxxxxxxx, mptcp@xxxxxxxxxxxxxxx, linux-hams@xxxxxxxxxxxxxxx, linux-rdma@xxxxxxxxxxxxxxx, rds-devel@xxxxxxxxxxxxxx, linux-afs@xxxxxxxxxxxxxxxxxxx, linux-sctp@xxxxxxxxxxxxxxx, linux-s390@xxxxxxxxxxxxxxx, linux-nfs@xxxxxxxxxxxxxxx, tipc-discussion@xxxxxxxxxxxxxxxxxxxxx, linux-x25@xxxxxxxxxxxxxxx, netfilter-devel@xxxxxxxxxxxxxxx, coreteam@xxxxxxxxxxxxx, bridge@xxxxxxxxxxxxxxx, lvs-devel@xxxxxxxxxxxxxxx, Joel Granados <j.granados@xxxxxxxxxxx>
From: Joel Granados via B4 Relay <devnull+j.granados.samsung.com@xxxxxxxxxx>
Date: Fri, 26 Apr 2024 12:46:54 +0200
From: Joel Granados <j.granados@xxxxxxxxxxx>

This commit comes at the tail end of a greater effort to remove the
empty elements at the end of the ctl_table arrays (sentinels) which
will reduce the overall build time size of the kernel and run time
memory bloat by ~64 bytes per sentinel (further information Link :
https://lore.kernel.org/all/ZO5Yx5JFogGi%2FcBo@xxxxxxxxxxxxxxxxxxxxxx/)

* Remove sentinel element from ctl_table structs.
* Remove the zeroing out of an array element (to make it look like a
  sentinel) in sysctl_route_net_init And ipv6_route_sysctl_init.
  This is not longer needed and is safe after commit c899710fe7f9
  ("networking: Update to register_net_sysctl_sz") added the array size
  to the ctl_table registration.
* Remove extra sentinel element in the declaration of devinet_vars.
* Removed the "-1" in __devinet_sysctl_register, sysctl_route_net_init,
  ipv6_sysctl_net_init and ipv4_sysctl_init_net that adjusted for having
  an extra empty element when looping over ctl_table arrays
* Replace the for loop stop condition in __addrconf_sysctl_register that
  tests for procname == NULL with one that depends on array size
* Removing the unprivileged user check in ipv6_route_sysctl_init is
  safe as it is replaced by calling ipv6_route_sysctl_table_size;
  introduced in commit c899710fe7f9 ("networking: Update to
  register_net_sysctl_sz")
* Use a table_size variable to keep the value of ARRAY_SIZE

Signed-off-by: Joel Granados <j.granados@xxxxxxxxxxx>
---
 net/ipv4/devinet.c         | 5 ++---
 net/ipv4/ip_fragment.c     | 2 --
 net/ipv4/route.c           | 8 ++------
 net/ipv4/sysctl_net_ipv4.c | 7 +++----
 net/ipv4/xfrm4_policy.c    | 1 -
 net/ipv6/addrconf.c        | 8 +++-----
 net/ipv6/icmp.c            | 1 -
 net/ipv6/reassembly.c      | 2 --
 net/ipv6/route.c           | 5 -----
 net/ipv6/sysctl_net_ipv6.c | 8 +++-----
 net/ipv6/xfrm6_policy.c    | 1 -
 11 files changed, 13 insertions(+), 35 deletions(-)

diff --git a/net/ipv4/devinet.c b/net/ipv4/devinet.c
index 7a437f0d4190..6195cc5be1fc 100644
--- a/net/ipv4/devinet.c
+++ b/net/ipv4/devinet.c
@@ -2515,7 +2515,7 @@ static int ipv4_doint_and_flush(struct ctl_table *ctl, 
int write,
 
 static struct devinet_sysctl_table {
        struct ctl_table_header *sysctl_header;
-       struct ctl_table devinet_vars[__IPV4_DEVCONF_MAX];
+       struct ctl_table devinet_vars[IPV4_DEVCONF_MAX];
 } devinet_sysctl = {
        .devinet_vars = {
                DEVINET_SYSCTL_COMPLEX_ENTRY(FORWARDING, "forwarding",
@@ -2578,7 +2578,7 @@ static int __devinet_sysctl_register(struct net *net, 
char *dev_name,
        if (!t)
                goto out;
 
-       for (i = 0; i < ARRAY_SIZE(t->devinet_vars) - 1; i++) {
+       for (i = 0; i < ARRAY_SIZE(t->devinet_vars); i++) {
                t->devinet_vars[i].data += (char *)p - (char *)&ipv4_devconf;
                t->devinet_vars[i].extra1 = p;
                t->devinet_vars[i].extra2 = net;
@@ -2652,7 +2652,6 @@ static struct ctl_table ctl_forward_entry[] = {
                .extra1         = &ipv4_devconf,
                .extra2         = &init_net,
        },
-       { },
 };
 #endif
 
diff --git a/net/ipv4/ip_fragment.c b/net/ipv4/ip_fragment.c
index a4941f53b523..e308779ed77b 100644
--- a/net/ipv4/ip_fragment.c
+++ b/net/ipv4/ip_fragment.c
@@ -580,7 +580,6 @@ static struct ctl_table ip4_frags_ns_ctl_table[] = {
                .proc_handler   = proc_dointvec_minmax,
                .extra1         = &dist_min,
        },
-       { }
 };
 
 /* secret interval has been deprecated */
@@ -593,7 +592,6 @@ static struct ctl_table ip4_frags_ctl_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
-       { }
 };
 
 static int __net_init ip4_frags_ns_ctl_register(struct net *net)
diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index c8f76f56dc16..deecfc0e5a91 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -3509,7 +3509,6 @@ static struct ctl_table ipv4_route_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
-       { }
 };
 
 static const char ipv4_route_flush_procname[] = "flush";
@@ -3543,7 +3542,6 @@ static struct ctl_table ipv4_route_netns_table[] = {
                .mode       = 0644,
                .proc_handler   = proc_dointvec,
        },
-       { },
 };
 
 static __net_init int sysctl_route_net_init(struct net *net)
@@ -3561,16 +3559,14 @@ static __net_init int sysctl_route_net_init(struct net 
*net)
 
                /* Don't export non-whitelisted sysctls to unprivileged users */
                if (net->user_ns != &init_user_ns) {
-                       if (tbl[0].procname != ipv4_route_flush_procname) {
-                               tbl[0].procname = NULL;
+                       if (tbl[0].procname != ipv4_route_flush_procname)
                                table_size = 0;
-                       }
                }
 
                /* Update the variables to point into the current struct net
                 * except for the first element flush
                 */
-               for (i = 1; i < ARRAY_SIZE(ipv4_route_netns_table) - 1; i++)
+               for (i = 1; i < table_size; i++)
                        tbl[i].data += (void *)net - (void *)&init_net;
        }
        tbl[0].extra1 = net;
diff --git a/net/ipv4/sysctl_net_ipv4.c b/net/ipv4/sysctl_net_ipv4.c
index 7e4f16a7dcc1..8b12bf195004 100644
--- a/net/ipv4/sysctl_net_ipv4.c
+++ b/net/ipv4/sysctl_net_ipv4.c
@@ -575,7 +575,6 @@ static struct ctl_table ipv4_table[] = {
                .extra1         = &sysctl_fib_sync_mem_min,
                .extra2         = &sysctl_fib_sync_mem_max,
        },
-       { }
 };
 
 static struct ctl_table ipv4_net_table[] = {
@@ -1502,11 +1501,11 @@ static struct ctl_table ipv4_net_table[] = {
                .proc_handler   = proc_dou8vec_minmax,
                .extra1         = SYSCTL_ONE,
        },
-       { }
 };
 
 static __net_init int ipv4_sysctl_init_net(struct net *net)
 {
+       size_t table_size = ARRAY_SIZE(ipv4_net_table);
        struct ctl_table *table;
 
        table = ipv4_net_table;
@@ -1517,7 +1516,7 @@ static __net_init int ipv4_sysctl_init_net(struct net 
*net)
                if (!table)
                        goto err_alloc;
 
-               for (i = 0; i < ARRAY_SIZE(ipv4_net_table) - 1; i++) {
+               for (i = 0; i < table_size; i++) {
                        if (table[i].data) {
                                /* Update the variables to point into
                                 * the current struct net
@@ -1533,7 +1532,7 @@ static __net_init int ipv4_sysctl_init_net(struct net 
*net)
        }
 
        net->ipv4.ipv4_hdr = register_net_sysctl_sz(net, "net/ipv4", table,
-                                                   ARRAY_SIZE(ipv4_net_table));
+                                                   table_size);
        if (!net->ipv4.ipv4_hdr)
                goto err_reg;
 
diff --git a/net/ipv4/xfrm4_policy.c b/net/ipv4/xfrm4_policy.c
index c33bca2c3841..4c74fec034c5 100644
--- a/net/ipv4/xfrm4_policy.c
+++ b/net/ipv4/xfrm4_policy.c
@@ -152,7 +152,6 @@ static struct ctl_table xfrm4_policy_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
-       { }
 };
 
 static __net_init int xfrm4_net_sysctl_init(struct net *net)
diff --git a/net/ipv6/addrconf.c b/net/ipv6/addrconf.c
index 247bd4d8ee45..6e7e8c4f1ab6 100644
--- a/net/ipv6/addrconf.c
+++ b/net/ipv6/addrconf.c
@@ -7181,14 +7181,12 @@ static const struct ctl_table addrconf_sysctl[] = {
                .extra1         = SYSCTL_ZERO,
                .extra2         = SYSCTL_TWO,
        },
-       {
-               /* sentinel */
-       }
 };
 
 static int __addrconf_sysctl_register(struct net *net, char *dev_name,
                struct inet6_dev *idev, struct ipv6_devconf *p)
 {
+       size_t table_size = ARRAY_SIZE(addrconf_sysctl);
        int i, ifindex;
        struct ctl_table *table;
        char path[sizeof("net/ipv6/conf/") + IFNAMSIZ];
@@ -7197,7 +7195,7 @@ static int __addrconf_sysctl_register(struct net *net, 
char *dev_name,
        if (!table)
                goto out;
 
-       for (i = 0; table[i].data; i++) {
+       for (i = 0; i < table_size; i++) {
                table[i].data += (char *)p - (char *)&ipv6_devconf;
                /* If one of these is already set, then it is not safe to
                 * overwrite either of them: this makes proc_dointvec_minmax
@@ -7212,7 +7210,7 @@ static int __addrconf_sysctl_register(struct net *net, 
char *dev_name,
        snprintf(path, sizeof(path), "net/ipv6/conf/%s", dev_name);
 
        p->sysctl_header = register_net_sysctl_sz(net, path, table,
-                                                 ARRAY_SIZE(addrconf_sysctl));
+                                                 table_size);
        if (!p->sysctl_header)
                goto free;
 
diff --git a/net/ipv6/icmp.c b/net/ipv6/icmp.c
index 1635da07285f..91cbf8e8009f 100644
--- a/net/ipv6/icmp.c
+++ b/net/ipv6/icmp.c
@@ -1206,7 +1206,6 @@ static struct ctl_table ipv6_icmp_table_template[] = {
                .extra1         = SYSCTL_ZERO,
                .extra2         = SYSCTL_ONE,
        },
-       { },
 };
 
 struct ctl_table * __net_init ipv6_icmp_sysctl_init(struct net *net)
diff --git a/net/ipv6/reassembly.c b/net/ipv6/reassembly.c
index acb4f119e11f..afb343cb77ac 100644
--- a/net/ipv6/reassembly.c
+++ b/net/ipv6/reassembly.c
@@ -436,7 +436,6 @@ static struct ctl_table ip6_frags_ns_ctl_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
-       { }
 };
 
 /* secret interval has been deprecated */
@@ -449,7 +448,6 @@ static struct ctl_table ip6_frags_ctl_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec_jiffies,
        },
-       { }
 };
 
 static int __net_init ip6_frags_ns_sysctl_register(struct net *net)
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index 1f4b935a0e57..b49137c3031b 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -6428,7 +6428,6 @@ static struct ctl_table ipv6_route_table_template[] = {
                .extra1         =       SYSCTL_ZERO,
                .extra2         =       SYSCTL_ONE,
        },
-       { }
 };
 
 struct ctl_table * __net_init ipv6_route_sysctl_init(struct net *net)
@@ -6452,10 +6451,6 @@ struct ctl_table * __net_init 
ipv6_route_sysctl_init(struct net *net)
                table[8].data = &net->ipv6.sysctl.ip6_rt_min_advmss;
                table[9].data = &net->ipv6.sysctl.ip6_rt_gc_min_interval;
                table[10].data = &net->ipv6.sysctl.skip_notify_on_dev_down;
-
-               /* Don't export sysctls to unprivileged users */
-               if (net->user_ns != &init_user_ns)
-                       table[1].procname = NULL;
        }
 
        return table;
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index 888676163e90..b8cbad351802 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -213,7 +213,6 @@ static struct ctl_table ipv6_table_template[] = {
                .proc_handler   = proc_doulongvec_minmax,
                .extra2         = &ioam6_id_wide_max,
        },
-       { }
 };
 
 static struct ctl_table ipv6_rotable[] = {
@@ -248,11 +247,11 @@ static struct ctl_table ipv6_rotable[] = {
                .proc_handler   = proc_dointvec,
        },
 #endif /* CONFIG_NETLABEL */
-       { }
 };
 
 static int __net_init ipv6_sysctl_net_init(struct net *net)
 {
+       size_t table_size = ARRAY_SIZE(ipv6_table_template);
        struct ctl_table *ipv6_table;
        struct ctl_table *ipv6_route_table;
        struct ctl_table *ipv6_icmp_table;
@@ -264,7 +263,7 @@ static int __net_init ipv6_sysctl_net_init(struct net *net)
        if (!ipv6_table)
                goto out;
        /* Update the variables to point into the current struct net */
-       for (i = 0; i < ARRAY_SIZE(ipv6_table_template) - 1; i++)
+       for (i = 0; i < table_size; i++)
                ipv6_table[i].data += (void *)net - (void *)&init_net;
 
        ipv6_route_table = ipv6_route_sysctl_init(net);
@@ -276,8 +275,7 @@ static int __net_init ipv6_sysctl_net_init(struct net *net)
                goto out_ipv6_route_table;
 
        net->ipv6.sysctl.hdr = register_net_sysctl_sz(net, "net/ipv6",
-                                                     ipv6_table,
-                                                     
ARRAY_SIZE(ipv6_table_template));
+                                                     ipv6_table, table_size);
        if (!net->ipv6.sysctl.hdr)
                goto out_ipv6_icmp_table;
 
diff --git a/net/ipv6/xfrm6_policy.c b/net/ipv6/xfrm6_policy.c
index 42fb6996b077..499b5f5c19fc 100644
--- a/net/ipv6/xfrm6_policy.c
+++ b/net/ipv6/xfrm6_policy.c
@@ -184,7 +184,6 @@ static struct ctl_table xfrm6_policy_table[] = {
                .mode           = 0644,
                .proc_handler   = proc_dointvec,
        },
-       { }
 };
 
 static int __net_init xfrm6_net_sysctl_init(struct net *net)

-- 
2.43.0




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