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Commit 92e47ba8 authored by Liping Zhang's avatar Liping Zhang Committed by Pablo Neira Ayuso
Browse files

netfilter: conntrack: simplify the code by using nf_conntrack_get_ht 



Since commit 64b87639 ("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: default avatarPablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: default avatarLiping Zhang <liping.zhang@spreadtrum.com>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent adf05168

include/net/netfilter/nf_conntrack.h

+20 −0
Original line number Diff line number Diff line
@@ -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);

include/net/netfilter/nf_conntrack_core.h

+0 −3
Original line number Diff line number Diff line
@@ -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);

net/netfilter/nf_conntrack_core.c

+10 −36
Original line number Diff line number Diff line
@@ -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();