Messages in this thread | | | Subject | Re: [PATCH] Reduce number of pointer dereferences in IPv6 netfilter LOG module function dump_packet() | From | Eric Dumazet <> | Date | Mon, 15 Nov 2010 01:50:15 +0100 |
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Le dimanche 14 novembre 2010 à 22:47 +0100, Jesper Juhl a écrit : > By adding two pointer variables to > net/ipv6/netfilter/ip6t_LOG.c::dump_packet() we can save 19 bytes of .text > and many pointer dereferences. > > before: > text data bss dec hex filename > 6258 600 3088 9946 26da net/ipv6/netfilter/ip6t_LOG.o > > after: > text data bss dec hex filename > 6239 600 3088 9927 26c7 net/ipv6/netfilter/ip6t_LOG.o > > > Please Cc me on replies. > > > Signed-off-by: Jesper Juhl <jj@chaosbits.net> > --- > ip6t_LOG.c | 16 ++++++++++------ > 1 file changed, 10 insertions(+), 6 deletions(-) > > diff --git a/net/ipv6/netfilter/ip6t_LOG.c b/net/ipv6/netfilter/ip6t_LOG.c > index 09c8889..51d10a5 100644 > --- a/net/ipv6/netfilter/ip6t_LOG.c > +++ b/net/ipv6/netfilter/ip6t_LOG.c > @@ -46,6 +46,8 @@ static void dump_packet(struct sbuff *m, > unsigned int ptr; > unsigned int hdrlen = 0; > unsigned int logflags; > + struct sock *sk; > + struct socket *sk_socket; > > if (info->type == NF_LOG_TYPE_LOG) > logflags = info->u.log.logflags; > @@ -358,13 +360,15 @@ static void dump_packet(struct sbuff *m, > } > > /* Max length: 15 "UID=4294967295 " */ > - if ((logflags & IP6T_LOG_UID) && recurse && skb->sk) { > - read_lock_bh(&skb->sk->sk_callback_lock); > - if (skb->sk->sk_socket && skb->sk->sk_socket->file) > + sk = skb->sk; > + sk_socket = sk->sk_socket; > + if ((logflags & IP6T_LOG_UID) && recurse && sk) { > + read_lock_bh(&sk->sk_callback_lock); > + if (sk_socket && sk_socket->file) > sb_add(m, "UID=%u GID=%u ", > - skb->sk->sk_socket->file->f_cred->fsuid, > - skb->sk->sk_socket->file->f_cred->fsgid); > - read_unlock_bh(&skb->sk->sk_callback_lock); > + sk_socket->file->f_cred->fsuid, > + sk_socket->file->f_cred->fsgid); > + read_unlock_bh(&sk->sk_callback_lock); > } > > /* Max length: 16 "MARK=0xFFFFFFFF " */ > > >
Same comment than previous patch, you add a NULL dereference.
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