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netfilter: conntrack: simplify the code by using nf_conntrack_get_ht 

Since commit 64b87639c9 ("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>
This commit is contained in:
Liping Zhang 2016-08-13 22:35:36 +08:00 committed by Pablo Neira Ayuso
parent adf0516845
commit 92e47ba883
3 changed files with 30 additions and 39 deletions
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20
include/net/netfilter/nf_conntrack.h
View File

@ -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);

3
include/net/netfilter/nf_conntrack_core.h
View File

@ -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);

46
net/netfilter/nf_conntrack_core.c
View File

@ -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();