Commit 643d1260 authored by Florian Westphal's avatar Florian Westphal Committed by Pablo Neira Ayuso
Browse files

netfilter: conntrack: switch connlabels to atomic_t 



The spinlock is back from the day when connabels did not have
a fixed size and reallocation had to be supported.

Remove it.  This change also allows to call the helpers from
softirq or timers without deadlocks.

Also add WARN()s to catch refcounting imbalances.

Signed-off-by: default avatarFlorian Westphal <fw@strlen.de>
Signed-off-by: default avatarPablo Neira Ayuso <pablo@netfilter.org>
parent ee6f05dc

include/net/netfilter/nf_conntrack_labels.h

+1 −1
Original line number Diff line number Diff line
@@ -39,7 +39,7 @@ static inline struct nf_conn_labels *nf_ct_labels_ext_add(struct nf_conn *ct) 
#ifdef CONFIG_NF_CONNTRACK_LABELS

	struct net *net = nf_ct_net(ct);



	if (net->ct.labels_used == 0)

	if (atomic_read(&net->ct.labels_used) == 0)

		return NULL;



	return nf_ct_ext_add(ct, NF_CT_EXT_LABELS, GFP_ATOMIC);

include/net/netns/conntrack.h

+1 −1
Original line number Diff line number Diff line
@@ -107,7 +107,7 @@ struct netns_ct { 
	struct nf_ct_event_notifier __rcu *nf_conntrack_event_cb;

	struct nf_ip_net	nf_ct_proto;

#if defined(CONFIG_NF_CONNTRACK_LABELS)

	unsigned int		labels_used;

	atomic_t		labels_used;

#endif

};

#endif

net/netfilter/nf_conntrack_labels.c

+8 −9
Original line number Diff line number Diff line
@@ -11,8 +11,6 @@ 
#include <net/netfilter/nf_conntrack_ecache.h>

#include <net/netfilter/nf_conntrack_labels.h>



static DEFINE_SPINLOCK(nf_connlabels_lock);



static int replace_u32(u32 *address, u32 mask, u32 new)

{

	u32 old, tmp;
@@ -60,23 +58,24 @@ EXPORT_SYMBOL_GPL(nf_connlabels_replace); 


int nf_connlabels_get(struct net *net, unsigned int bits)

{

	int v;



	if (BIT_WORD(bits) >= NF_CT_LABELS_MAX_SIZE / sizeof(long))

		return -ERANGE;



	spin_lock(&nf_connlabels_lock);

	net->ct.labels_used++;

	spin_unlock(&nf_connlabels_lock);



	BUILD_BUG_ON(NF_CT_LABELS_MAX_SIZE / sizeof(long) >= U8_MAX);



	v = atomic_inc_return_relaxed(&net->ct.labels_used);

	WARN_ON_ONCE(v <= 0);



	return 0;

}

EXPORT_SYMBOL_GPL(nf_connlabels_get);



void nf_connlabels_put(struct net *net)

{

	spin_lock(&nf_connlabels_lock);

	net->ct.labels_used--;

	spin_unlock(&nf_connlabels_lock);

	int v = atomic_dec_return_relaxed(&net->ct.labels_used);



	WARN_ON_ONCE(v < 0);

}

EXPORT_SYMBOL_GPL(nf_connlabels_put);