lkml.org 
[lkml]   [2010]   [Nov]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
From
Subject[PATCH] Reduce number of pointer dereferences in IPv4 netfilter LOG module function dump_packet()

By adding two pointer variables to
net/ipv4/netfilter/ipt_LOG.c::dump_packet() we can save 16 bytes of .text
and 9 pointer dereferences.

before this patch we did 20 pointer dereferences and had this object file
size:
text data bss dec hex filename
6233 600 3080 9913 26b9 net/ipv4/netfilter/ipt_LOG.o

after this patch we do just 11 pointer dereferences and have this object
file size:
text data bss dec hex filename
6217 600 3080 9897 26a9 net/ipv4/netfilter/ipt_LOG.o


Please Cc me on replies.


Signed-off-by: Jesper Juhl <jj@chaosbits.net>
---
ipt_LOG.c | 16 ++++++++++------
1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/net/ipv4/netfilter/ipt_LOG.c b/net/ipv4/netfilter/ipt_LOG.c
index 72ffc8f..02a92de 100644
--- a/net/ipv4/netfilter/ipt_LOG.c
+++ b/net/ipv4/netfilter/ipt_LOG.c
@@ -39,6 +39,8 @@ static void dump_packet(struct sbuff *m,
struct iphdr _iph;
const struct iphdr *ih;
unsigned int logflags;
+ struct sock *sk;
+ struct socket *sk_socket;

if (info->type == NF_LOG_TYPE_LOG)
logflags = info->u.log.logflags;
@@ -335,13 +337,15 @@ static void dump_packet(struct sbuff *m,
}

/* Max length: 15 "UID=4294967295 " */
- if ((logflags & IPT_LOG_UID) && !iphoff && 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 & IPT_LOG_UID) && !iphoff && 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 " */


--
Jesper Juhl <jj@chaosbits.net> http://www.chaosbits.net/
Don't top-post http://www.catb.org/~esr/jargon/html/T/top-post.html
Plain text mails only, please.



\
 
 \ /
  Last update: 2010-11-14 22:51    [W:0.028 / U:0.692 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site