[Devel] [PATCH rh7 18/19] ms/netfilter: conntrack: use single slab cache

[Konstantin Khorenko]

From: Florian Westphal <fw at strlen.de>

An earlier patch changed lookup side to also net_eq() namespaces after
obtaining a reference on the conntrack, so a single kmemcache can be used.

Signed-off-by: Florian Westphal <fw at strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo at netfilter.org>

https://jira.sw.ru/browse/PSBM-103515

(cherry picked from commit 0c5366b3a8c77fd6d67b763c5a76dfdc314e7726)
Signed-off-by: Konstantin Khorenko <khorenko at virtuozzo.com>
---
 include/net/netns/conntrack.h     |  2 --
 net/netfilter/nf_conntrack_core.c | 38 ++++++++++++++------------------------
 2 files changed, 14 insertions(+), 26 deletions(-)

diff --git a/include/net/netns/conntrack.h b/include/net/netns/conntrack.h
index 7f921295d020e..9bb9edef8611a 100644
--- a/include/net/netns/conntrack.h
+++ b/include/net/netns/conntrack.h
@@ -120,7 +120,6 @@ struct netns_ct {
 	struct ctl_table_header	*event_sysctl_header;
 	struct ctl_table_header	*helper_sysctl_header;
 #endif
-	char			*slabname;
 	unsigned int		sysctl_log_invalid; /* Log invalid packets */
 	unsigned int		sysctl_events_retry_timeout;
 	int			sysctl_events;
@@ -131,7 +130,6 @@ struct netns_ct {
 	int			sysctl_checksum;
 
 	RH_KABI_DEPRECATE(seqcount_t, generation)
-	struct kmem_cache	*nf_conntrack_cachep;
 
 	/* next three hlist heads are unused in RHEL,
 	 * only kept for ABI compatibility. */
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index aca113963fed9..1c8223e006b18 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -78,6 +78,7 @@ EXPORT_SYMBOL_GPL(nf_conntrack_expect_lock);
 struct hlist_nulls_head *nf_conntrack_hash __read_mostly;
 EXPORT_SYMBOL_GPL(nf_conntrack_hash);
 
+static __read_mostly struct kmem_cache *nf_conntrack_cachep;
 static __read_mostly seqcount_t nf_conntrack_generation;
 
 static void nf_conntrack_double_unlock(unsigned int h1, unsigned int h2)
@@ -1003,7 +1004,7 @@ __nf_conntrack_alloc(struct net *net,
 	 * Do not use kmem_cache_zalloc(), as this cache uses
 	 * SLAB_DESTROY_BY_RCU.
 	 */
-	ct = kmem_cache_alloc(net->ct.nf_conntrack_cachep, gfp);
+	ct = kmem_cache_alloc(nf_conntrack_cachep, gfp);
 	if (ct == NULL)
 		goto out;
 
@@ -1033,7 +1034,7 @@ __nf_conntrack_alloc(struct net *net,
 	atomic_set(&ct->ct_general.use, 0);
 	return ct;
 out_free:
-	kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
+	kmem_cache_free(nf_conntrack_cachep, ct);
 out:
 	atomic_dec(&net->ct.count);
 	return ERR_PTR(-ENOMEM);
@@ -1060,7 +1061,7 @@ void nf_conntrack_free(struct nf_conn *ct)
 
 	nf_ct_ext_destroy(ct);
 	nf_ct_ext_free(ct);
-	kmem_cache_free(net->ct.nf_conntrack_cachep, ct);
+	kmem_cache_free(nf_conntrack_cachep, ct);
 	smp_mb__before_atomic_dec();
 	atomic_dec(&net->ct.count);
 }
@@ -1705,8 +1706,6 @@ void nf_conntrack_cleanup_net_list(struct list_head *net_exit_list)
 		nf_conntrack_tstamp_pernet_fini(net);
 		nf_conntrack_acct_pernet_fini(net);
 		nf_conntrack_expect_pernet_fini(net);
-		kmem_cache_destroy(net->ct.nf_conntrack_cachep);
-		kfree(net->ct.slabname);
 		free_percpu(net->ct.stat);
 		free_percpu(net->ct.pcpu_lists);
 	}
@@ -1804,7 +1803,8 @@ module_param_call(hashsize, nf_conntrack_set_hashsize, param_get_uint,
 int nf_conntrack_init_start(void)
 {
 	int max_factor = 8;
-	int i, ret;
+	int ret = -ENOMEM;
+	int i;
 
 	seqcount_init(&nf_conntrack_generation);
 
@@ -1840,6 +1840,12 @@ int nf_conntrack_init_start(void)
 
 	init_net.ct.max = max_factor * nf_conntrack_htable_size;
 
+	nf_conntrack_cachep = kmem_cache_create("nf_conntrack",
+						sizeof(struct nf_conn), 0,
+						SLAB_DESTROY_BY_RCU, NULL);
+	if (!nf_conntrack_cachep)
+		goto err_cachep;
+
 	printk(KERN_INFO "nf_conntrack version %s (%u buckets, %d max)\n",
 	       NF_CONNTRACK_VERSION, nf_conntrack_htable_size,
 	       init_net.ct.max);
@@ -1908,6 +1914,8 @@ int nf_conntrack_init_start(void)
 err_acct:
 	nf_conntrack_expect_fini();
 err_expect:
+	kmem_cache_destroy(nf_conntrack_cachep);
+err_cachep:
 	nf_ct_free_hashtable(nf_conntrack_hash, nf_conntrack_htable_size);
 	return ret;
 }
@@ -1928,7 +1936,6 @@ void nf_conntrack_init_end(void)
 
 int nf_conntrack_init_net(struct net *net)
 {
-	static atomic64_t unique_id;
 	int ret = -ENOMEM;
 	int cpu;
 
@@ -1952,19 +1959,6 @@ int nf_conntrack_init_net(struct net *net)
 	if (!net->ct.stat)
 		goto err_pcpu_lists;
 
-	net->ct.slabname = kasprintf(GFP_KERNEL, "nf_conntrack_%llu",
-				(u64)atomic64_inc_return(&unique_id));
-	if (!net->ct.slabname)
-		goto err_slabname;
-
-	net->ct.nf_conntrack_cachep = kmem_cache_create(net->ct.slabname,
-							sizeof(struct nf_conn), 0,
-							SLAB_DESTROY_BY_RCU, NULL);
-	if (!net->ct.nf_conntrack_cachep) {
-		printk(KERN_ERR "Unable to create nf_conn slab cache\n");
-		goto err_cache;
-	}
-
 	ret = nf_conntrack_expect_pernet_init(net);
 	if (ret < 0)
 		goto err_expect;
@@ -1996,10 +1990,6 @@ int nf_conntrack_init_net(struct net *net)
 err_acct:
 	nf_conntrack_expect_pernet_fini(net);
 err_expect:
-	kmem_cache_destroy(net->ct.nf_conntrack_cachep);
-err_cache:
-	kfree(net->ct.slabname);
-err_slabname:
 	free_percpu(net->ct.stat);
 err_pcpu_lists:
 	free_percpu(net->ct.pcpu_lists);
-- 
2.15.1