netfilter: conntrack: simplify the code by using nf_conntrack_get_ht
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@netfilter.org>
Signed-off-by: Liping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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();