netdev - [PATCH v2 net-next 03/12] ipv4: fib: Allocate fib_info

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Message-ID: <20250226192556.21633-4-kuniyu@amazon.com>
Date: Wed, 26 Feb 2025 11:25:47 -0800
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: "David S. Miller" <davem@...emloft.net>, David Ahern <dsahern@...nel.org>,
	Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>, "Paolo
 Abeni" <pabeni@...hat.com>, Simon Horman <horms@...nel.org>
CC: Kuniyuki Iwashima <kuniyu@...zon.com>, Kuniyuki Iwashima
	<kuni1840@...il.com>, <netdev@...r.kernel.org>
Subject: [PATCH v2 net-next 03/12] ipv4: fib: Allocate fib_info_hash[] during netns initialisation.

We will allocate fib_info_hash[] and fib_info_laddrhash[] for each netns.

Currently, fib_info_hash[] is allocated when the first route is added.

Let's move the first allocation to a new __net_init function.

Note that we must call fib4_semantics_exit() in fib_net_exit_batch()
because ->exit() is called earlier than ->exit_batch().

Signed-off-by: Kuniyuki Iwashima <kuniyu@...zon.com>
---
v2:
  * Fix memleak by calling fib4_semantics_exit() properly
  * Move fib4_semantics_exit() to fib_net_exit_batch()
---
 include/net/ip_fib.h     |  2 ++
 net/ipv4/fib_frontend.c  | 11 ++++++++++
 net/ipv4/fib_semantics.c | 45 ++++++++++++++++++++++++++++------------
 3 files changed, 45 insertions(+), 13 deletions(-)

diff --git a/include/net/ip_fib.h b/include/net/ip_fib.h
index a113c11ab56b..e3864b74e92a 100644
--- a/include/net/ip_fib.h
+++ b/include/net/ip_fib.h
@@ -162,6 +162,8 @@ struct fib_info {
 	struct fib_nh		fib_nh[] __counted_by(fib_nhs);
 };
 
+int __net_init fib4_semantics_init(struct net *net);
+void __net_exit fib4_semantics_exit(struct net *net);
 
 #ifdef CONFIG_IP_MULTIPLE_TABLES
 struct fib_rule;
diff --git a/net/ipv4/fib_frontend.c b/net/ipv4/fib_frontend.c
index 6730e2034cf8..40c062f820f2 100644
--- a/net/ipv4/fib_frontend.c
+++ b/net/ipv4/fib_frontend.c
@@ -1615,9 +1615,15 @@ static int __net_init fib_net_init(struct net *net)
 	error = ip_fib_net_init(net);
 	if (error < 0)
 		goto out;
+
+	error = fib4_semantics_init(net);
+	if (error)
+		goto out_semantics;
+
 	error = nl_fib_lookup_init(net);
 	if (error < 0)
 		goto out_nlfl;
+
 	error = fib_proc_init(net);
 	if (error < 0)
 		goto out_proc;
@@ -1627,6 +1633,8 @@ static int __net_init fib_net_init(struct net *net)
 out_proc:
 	nl_fib_lookup_exit(net);
 out_nlfl:
+	fib4_semantics_exit(net);
+out_semantics:
 	rtnl_lock();
 	ip_fib_net_exit(net);
 	rtnl_unlock();
@@ -1648,6 +1656,9 @@ static void __net_exit fib_net_exit_batch(struct list_head *net_list)
 		ip_fib_net_exit(net);
 
 	rtnl_unlock();
+
+	list_for_each_entry(net, net_list, exit_list)
+		fib4_semantics_exit(net);
 }
 
 static struct pernet_operations fib_net_ops = {
diff --git a/net/ipv4/fib_semantics.c b/net/ipv4/fib_semantics.c
index a68a4eb5e0d1..f00ac983861a 100644
--- a/net/ipv4/fib_semantics.c
+++ b/net/ipv4/fib_semantics.c
@@ -1421,28 +1421,21 @@ struct fib_info *fib_create_info(struct fib_config *cfg,
 	}
 #endif
 
-	err = -ENOBUFS;
-
 	if (fib_info_cnt >= fib_info_hash_size) {
+		unsigned int new_hash_bits = fib_info_hash_bits + 1;
 		struct hlist_head *new_info_hash;
-		unsigned int new_hash_bits;
-
-		if (!fib_info_hash_bits)
-			new_hash_bits = 4;
-		else
-			new_hash_bits = fib_info_hash_bits + 1;
 
 		new_info_hash = fib_info_hash_alloc(new_hash_bits);
 		if (new_info_hash)
 			fib_info_hash_move(new_info_hash, 1 << new_hash_bits);
-
-		if (!fib_info_hash_size)
-			goto failure;
 	}
 
 	fi = kzalloc(struct_size(fi, fib_nh, nhs), GFP_KERNEL);
-	if (!fi)
+	if (!fi) {
+		err = -ENOBUFS;
 		goto failure;
+	}
+
 	fi->fib_metrics = ip_fib_metrics_init(cfg->fc_mx, cfg->fc_mx_len, extack);
 	if (IS_ERR(fi->fib_metrics)) {
 		err = PTR_ERR(fi->fib_metrics);
@@ -1863,7 +1856,7 @@ int fib_sync_down_addr(struct net_device *dev, __be32 local)
 	struct fib_info *fi;
 	int ret = 0;
 
-	if (!fib_info_laddrhash || local == 0)
+	if (!local)
 		return 0;
 
 	head = fib_info_laddrhash_bucket(net, local);
@@ -2265,3 +2258,29 @@ void fib_select_path(struct net *net, struct fib_result *res,
 			fl4->saddr = inet_select_addr(l3mdev, 0, RT_SCOPE_LINK);
 	}
 }
+
+int __net_init fib4_semantics_init(struct net *net)
+{
+	unsigned int hash_bits = 4;
+
+	if (!net_eq(net, &init_net))
+		return 0;
+
+	fib_info_hash = fib_info_hash_alloc(hash_bits);
+	if (!fib_info_hash)
+		return -ENOMEM;
+
+	fib_info_hash_bits = hash_bits;
+	fib_info_hash_size = 1 << hash_bits;
+	fib_info_laddrhash = fib_info_hash + fib_info_hash_size;
+
+	return 0;
+}
+
+void __net_exit fib4_semantics_exit(struct net *net)
+{
+	if (!net_eq(net, &init_net))
+		return;
+
+	fib_info_hash_free(fib_info_hash);
+}
-- 
2.39.5 (Apple Git-154)