[PATCH v1 net-next 1/2] ipv4: fib: Define fib_table_hash_lock under CONFIG_IP_MULTIPLE_TABLES.

[Kuniyuki Iwashima <kuniyu@google.com>]

When CONFIG_IP_MULTIPLE_TABLES is disabled, fib_new_table()
is fib_get_table(), and no new table is created.

Let's move net->ipv4.fib_table_hash_lock under
CONFIG_IP_MULTIPLE_TABLES.

While at it, netns_ipv4_sysctl.rst is updated.

Suggested-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: Kuniyuki Iwashima <kuniyu@google.com>
---
 Documentation/networking/net_cachelines/netns_ipv4_sysctl.rst | 1 +
 include/net/netns/ipv4.h                                      | 2 +-
 net/ipv4/fib_frontend.c                                       | 3 +++
 3 files changed, 5 insertions(+), 1 deletion(-)

diff --git a/Documentation/networking/net_cachelines/netns_ipv4_sysctl.rst b/Documentation/networking/net_cachelines/netns_ipv4_sysctl.rst
index 6dbd97d435e9..3dc03bff739e 100644
--- a/Documentation/networking/net_cachelines/netns_ipv4_sysctl.rst
+++ b/Documentation/networking/net_cachelines/netns_ipv4_sysctl.rst
@@ -22,6 +22,7 @@ struct_mutex                    ra_mutex
 struct_fib_rules_ops*           rules_ops
 struct_fib_table                fib_main
 struct_fib_table                fib_default
+spinlock_t                      fib_table_hash_lock
 unsigned_int                    fib_rules_require_fldissect
 bool                            fib_has_custom_rules
 bool                            fib_has_custom_local_routes
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 59506320558a..cb7f8bf15671 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -118,6 +118,7 @@ struct netns_ipv4 {
 	struct fib_rules_ops	*rules_ops;
 	struct fib_table __rcu	*fib_main;
 	struct fib_table __rcu	*fib_default;
+	spinlock_t		fib_table_hash_lock;
 	unsigned int		fib_rules_require_fldissect;
 	bool			fib_has_custom_rules;
 #endif
@@ -127,7 +128,6 @@ struct netns_ipv4 {
 	atomic_t		fib_num_tclassid_users;
 #endif
 	struct hlist_head	*fib_table_hash;
-	spinlock_t		fib_table_hash_lock;
 	struct sock		*fibnl;
 	struct hlist_head	*fib_info_hash;
 	unsigned int		fib_info_hash_bits;
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 54eb72695093..6f5d0d25b110 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1584,7 +1584,10 @@ static int __net_init ip_fib_net_init(struct net *net)
 	net->ipv4.sysctl_fib_multipath_hash_fields =
 		FIB_MULTIPATH_HASH_FIELD_DEFAULT_MASK;
 #endif
+
+#ifdef CONFIG_IP_MULTIPLE_TABLES
 	spin_lock_init(&net->ipv4.fib_table_hash_lock);
+#endif
 
 	/* Avoid false sharing : Use at least a full cache line */
 	size = max_t(size_t, size, L1_CACHE_BYTES);
-- 
2.55.0.rc0.799.gd6f94ed593-goog