From: Eric Dumazet <edumazet@google.com>
Date: Wed, 13 Jun 2018 17:11:56 +0000 (-0700)
Subject: netfilter: ipv6: nf_defrag: reduce struct net memory waste
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=69c471908ddd7b9927aa0735766d486cbf094cab;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git

netfilter: ipv6: nf_defrag: reduce struct net memory waste

[ Upstream commit 9ce7bc036ae4cfe3393232c86e9e1fea2153c237 ]

It is a waste of memory to use a full "struct netns_sysctl_ipv6"
while only one pointer is really used, considering netns_sysctl_ipv6
keeps growing.

Also, since "struct netns_frags" has cache line alignment,
it is better to move the frags_hdr pointer outside, otherwise
we spend a full cache line for this pointer.

This saves 192 bytes of memory per netns.

Fixes: c038a767cd69 ("ipv6: add a new namespace for nf_conntrack_reasm")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index 049008493faf..f4bf75fac349 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -120,6 +120,7 @@ struct net {
 #endif
 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
 	struct netns_nf_frag	nf_frag;
+	struct ctl_table_header *nf_frag_frags_hdr;
 #endif
 	struct sock		*nfnl;
 	struct sock		*nfnl_stash;
diff --git a/include/net/netns/ipv6.h b/include/net/netns/ipv6.h
index dc825a5ddd7f..c004d051c2d3 100644
--- a/include/net/netns/ipv6.h
+++ b/include/net/netns/ipv6.h
@@ -94,7 +94,6 @@ struct netns_ipv6 {
 
 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
 struct netns_nf_frag {
-	struct netns_sysctl_ipv6 sysctl;
 	struct netns_frags	frags;
 };
 #endif
diff --git a/net/ipv6/netfilter/nf_conntrack_reasm.c b/net/ipv6/netfilter/nf_conntrack_reasm.c
index 722a9db8c6a7..ee33a6743f3b 100644
--- a/net/ipv6/netfilter/nf_conntrack_reasm.c
+++ b/net/ipv6/netfilter/nf_conntrack_reasm.c
@@ -117,7 +117,7 @@ static int nf_ct_frag6_sysctl_register(struct net *net)
 	if (hdr == NULL)
 		goto err_reg;
 
-	net->nf_frag.sysctl.frags_hdr = hdr;
+	net->nf_frag_frags_hdr = hdr;
 	return 0;
 
 err_reg:
@@ -131,8 +131,8 @@ static void __net_exit nf_ct_frags6_sysctl_unregister(struct net *net)
 {
 	struct ctl_table *table;
 
-	table = net->nf_frag.sysctl.frags_hdr->ctl_table_arg;
-	unregister_net_sysctl_table(net->nf_frag.sysctl.frags_hdr);
+	table = net->nf_frag_frags_hdr->ctl_table_arg;
+	unregister_net_sysctl_table(net->nf_frag_frags_hdr);
 	if (!net_eq(net, &init_net))
 		kfree(table);
 }