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| author |   Florian Westphal <fw@strlen.de> | 2022-01-07 05:03:25 +0100 |
|---|---|---|
| committer |   Pablo Neira Ayuso <pablo@netfilter.org> | 2022-01-09 23:30:13 +0100 |
| commit | 6ae7989c9af0d98ab64196f4f4c6f6499454bd23 (patch) | |
| tree | e351c62322a77c4fe66cb8382070fb5d69db0b63 /include/net | |
| parent | netfilter: make function op structures const (diff) | |
| download | linux-dev-6ae7989c9af0d98ab64196f4f4c6f6499454bd23.tar.xz linux-dev-6ae7989c9af0d98ab64196f4f4c6f6499454bd23.zip | |
netfilter: conntrack: avoid useless indirection during conntrack destruction
nf_ct_put() results in a usesless indirection:
nf_ct_put -> nf_conntrack_put -> nf_conntrack_destroy -> rcu readlock +
indirect call of ct_hooks->destroy().
There are two _put helpers:
nf_ct_put and nf_conntrack_put. The latter is what should be used in
code that MUST NOT cause a linker dependency on the conntrack module
(e.g. calls from core network stack).
Everyone else should call nf_ct_put() instead.
A followup patch will convert a few nf_conntrack_put() calls to
nf_ct_put(), in particular from modules that already have a conntrack
dependency such as act_ct or even nf_conntrack itself.
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Diffstat (limited to 'include/net')
| -rw-r--r-- | include/net/netfilter/nf_conntrack.h | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/include/net/netfilter/nf_conntrack.h b/include/net/netfilter/nf_conntrack.h index a4a14f3a5e38..8731d5bcb47d 100644 --- a/include/net/netfilter/nf_conntrack.h +++ b/include/net/netfilter/nf_conntrack.h @@ -76,6 +76,8 @@ struct nf_conn { * Hint, SKB address this struct and refcnt via skb->_nfct and * helpers nf_conntrack_get() and nf_conntrack_put(). * Helper nf_ct_put() equals nf_conntrack_put() by dec refcnt, + * except that the latter uses internal indirection and does not + * result in a conntrack module dependency. * beware nf_ct_get() is different and don't inc refcnt. */ struct nf_conntrack ct_general; @@ -170,11 +172,13 @@ nf_ct_get(const struct sk_buff *skb, enum ip_conntrack_info *ctinfo) return (struct nf_conn *)(nfct & NFCT_PTRMASK); } +void nf_ct_destroy(struct nf_conntrack *nfct); + /* decrement reference count on a conntrack */ static inline void nf_ct_put(struct nf_conn *ct) { - WARN_ON(!ct); - nf_conntrack_put(&ct->ct_general); + if (ct && refcount_dec_and_test(&ct->ct_general.use)) + nf_ct_destroy(&ct->ct_general); } /* Protocol module loading */ |