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Date: Mon, 5 Sep 2016 12:58:24 +0200
From: Pablo Neira Ayuso <pablo@...filter.org>
To: netfilter-devel@...r.kernel.org
Cc: davem@...emloft.net, netdev@...r.kernel.org
Subject: [PATCH 09/29] netfilter: conntrack: simplify the code by using nf_conntrack_get_ht
From: Liping Zhang <liping.zhang@...eadtrum.com>
Since commit 64b87639c9cb ("netfilter: conntrack: fix race between
nf_conntrack proc read and hash resize") introduce the
nf_conntrack_get_ht, so there's no need to check nf_conntrack_generation
again and again to get the hash table and hash size. And convert
nf_conntrack_get_ht to inline function here.
Suggested-by: Pablo Neira Ayuso <pablo@...filter.org>
Signed-off-by: Liping Zhang <liping.zhang@...eadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@...filter.org>
---
include/net/netfilter/nf_conntrack.h | 20 ++++++++++++++
include/net/netfilter/nf_conntrack_core.h | 3 --
net/netfilter/nf_conntrack_core.c | 46 +++++++------------------------
3 files changed, 30 insertions(+), 39 deletions(-)
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h
index 445b019..2a12748 100644
--- a/include/net/netfilter/nf_conntrack.h
+++ b/include/net/netfilter/nf_conntrack.h
@@ -303,9 +303,29 @@ struct kernel_param;
int nf_conntrack_set_hashsize(const char *val, struct kernel_param *kp);
int nf_conntrack_hash_resize(unsigned int hashsize);
+
+extern struct hlist_nulls_head *nf_conntrack_hash;
extern unsigned int nf_conntrack_htable_size;
+extern seqcount_t nf_conntrack_generation;
extern unsigned int nf_conntrack_max;
+/* must be called with rcu read lock held */
+static inline void
+nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
+{
+ struct hlist_nulls_head *hptr;
+ unsigned int sequence, hsz;
+
+ do {
+ sequence = read_seqcount_begin(&nf_conntrack_generation);
+ hsz = nf_conntrack_htable_size;
+ hptr = nf_conntrack_hash;
+ } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
+
+ *hash = hptr;
+ *hsize = hsz;
+}
+
struct nf_conn *nf_ct_tmpl_alloc(struct net *net,
const struct nf_conntrack_zone *zone,
gfp_t flags);
diff --git a/include/net/netfilter/nf_conntrack_core.h b/include/net/netfilter/nf_conntrack_core.h
index 79d7ac5..62e17d1 100644
--- a/include/net/netfilter/nf_conntrack_core.h
+++ b/include/net/netfilter/nf_conntrack_core.h
@@ -51,8 +51,6 @@ bool nf_ct_invert_tuple(struct nf_conntrack_tuple *inverse,
const struct nf_conntrack_l3proto *l3proto,
const struct nf_conntrack_l4proto *l4proto);
-void nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize);
-
/* Find a connection corresponding to a tuple. */
struct nf_conntrack_tuple_hash *
nf_conntrack_find_get(struct net *net,
@@ -83,7 +81,6 @@ print_tuple(struct seq_file *s, const struct nf_conntrack_tuple *tuple,
#define CONNTRACK_LOCKS 1024
-extern struct hlist_nulls_head *nf_conntrack_hash;
extern spinlock_t nf_conntrack_locks[CONNTRACK_LOCKS];
void nf_conntrack_lock(spinlock_t *lock);
diff --git a/net/netfilter/nf_conntrack_core.c b/net/netfilter/nf_conntrack_core.c
index 22558b7..aeba28c 100644
--- a/net/netfilter/nf_conntrack_core.c
+++ b/net/netfilter/nf_conntrack_core.c
@@ -74,7 +74,6 @@ EXPORT_SYMBOL_GPL(nf_conntrack_hash);
static __read_mostly struct kmem_cache *nf_conntrack_cachep;
static __read_mostly spinlock_t nf_conntrack_locks_all_lock;
-static __read_mostly seqcount_t nf_conntrack_generation;
static __read_mostly DEFINE_SPINLOCK(nf_conntrack_locks_all_lock);
static __read_mostly bool nf_conntrack_locks_all;
@@ -162,6 +161,7 @@ static void nf_conntrack_all_unlock(void)
unsigned int nf_conntrack_htable_size __read_mostly;
unsigned int nf_conntrack_max __read_mostly;
+seqcount_t nf_conntrack_generation __read_mostly;
DEFINE_PER_CPU(struct nf_conn, nf_conntrack_untracked);
EXPORT_PER_CPU_SYMBOL(nf_conntrack_untracked);
@@ -478,23 +478,6 @@ nf_ct_key_equal(struct nf_conntrack_tuple_hash *h,
net_eq(net, nf_ct_net(ct));
}
-/* must be called with rcu read lock held */
-void nf_conntrack_get_ht(struct hlist_nulls_head **hash, unsigned int *hsize)
-{
- struct hlist_nulls_head *hptr;
- unsigned int sequence, hsz;
-
- do {
- sequence = read_seqcount_begin(&nf_conntrack_generation);
- hsz = nf_conntrack_htable_size;
- hptr = nf_conntrack_hash;
- } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
-
- *hash = hptr;
- *hsize = hsz;
-}
-EXPORT_SYMBOL_GPL(nf_conntrack_get_ht);
-
/*
* Warning :
* - Caller must take a reference on returned object
@@ -507,14 +490,11 @@ ____nf_conntrack_find(struct net *net, const struct nf_conntrack_zone *zone,
struct nf_conntrack_tuple_hash *h;
struct hlist_nulls_head *ct_hash;
struct hlist_nulls_node *n;
- unsigned int bucket, sequence;
+ unsigned int bucket, hsize;
begin:
- do {
- sequence = read_seqcount_begin(&nf_conntrack_generation);
- bucket = scale_hash(hash);
- ct_hash = nf_conntrack_hash;
- } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
+ nf_conntrack_get_ht(&ct_hash, &hsize);
+ bucket = reciprocal_scale(hash, hsize);
hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[bucket], hnnode) {
if (nf_ct_key_equal(h, tuple, zone, net)) {
@@ -820,18 +800,15 @@ nf_conntrack_tuple_taken(const struct nf_conntrack_tuple *tuple,
const struct nf_conntrack_zone *zone;
struct nf_conntrack_tuple_hash *h;
struct hlist_nulls_head *ct_hash;
- unsigned int hash, sequence;
+ unsigned int hash, hsize;
struct hlist_nulls_node *n;
struct nf_conn *ct;
zone = nf_ct_zone(ignored_conntrack);
rcu_read_lock();
- do {
- sequence = read_seqcount_begin(&nf_conntrack_generation);
- hash = hash_conntrack(net, tuple);
- ct_hash = nf_conntrack_hash;
- } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
+ nf_conntrack_get_ht(&ct_hash, &hsize);
+ hash = __hash_conntrack(net, tuple, hsize);
hlist_nulls_for_each_entry_rcu(h, n, &ct_hash[hash], hnnode) {
ct = nf_ct_tuplehash_to_ctrack(h);
@@ -897,14 +874,11 @@ static noinline int early_drop(struct net *net, unsigned int _hash)
for (i = 0; i < NF_CT_EVICTION_RANGE; i++) {
struct hlist_nulls_head *ct_hash;
- unsigned hash, sequence, drops;
+ unsigned int hash, hsize, drops;
rcu_read_lock();
- do {
- sequence = read_seqcount_begin(&nf_conntrack_generation);
- hash = scale_hash(_hash++);
- ct_hash = nf_conntrack_hash;
- } while (read_seqcount_retry(&nf_conntrack_generation, sequence));
+ nf_conntrack_get_ht(&ct_hash, &hsize);
+ hash = reciprocal_scale(_hash++, hsize);
drops = early_drop_list(net, &ct_hash[hash]);
rcu_read_unlock();
--
2.1.4
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