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When iterating the UDP inpcb list processing an inbound broadcast

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or multicast packet, we don't need to acquire the inpcb mutex
unless we are actually using inpcb fields other than the bound port
and address.  Since we hold the pcbinfo lock already, these can't
change.  Defer acquiring the inpcb mutex until we have a high
chance of a match.  This avoids about 120 mutex operations per UDP
broadcast packet received on one of my work systems.

Reviewed by:	sam
This commit is contained in:
Robert Watson 2004-08-06 02:08:31 +00:00
parent 17dbe0f79f
commit 9c1df6951f
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=133189
1 changed files with 9 additions and 10 deletions
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19
sys/netinet/udp_usrreq.c
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@ -287,26 +287,23 @@ udp_input(m, off)
*/
last = NULL;
LIST_FOREACH(inp, &udb, inp_list) {
INP_LOCK(inp);
if (inp->inp_lport != uh->uh_dport) {
docontinue:
INP_UNLOCK(inp);
if (inp->inp_lport != uh->uh_dport)
continue;
}
#ifdef INET6
if ((inp->inp_vflag & INP_IPV4) == 0)
goto docontinue;
continue;
#endif
if (inp->inp_laddr.s_addr != INADDR_ANY) {
if (inp->inp_laddr.s_addr != ip->ip_dst.s_addr)
goto docontinue;
continue;
}
if (inp->inp_faddr.s_addr != INADDR_ANY) {
if (inp->inp_faddr.s_addr !=
ip->ip_src.s_addr ||
inp->inp_fport != uh->uh_sport)
goto docontinue;
continue;
}
INP_LOCK(inp);
/*
* Check multicast packets to make sure they are only
@ -327,8 +324,10 @@ udp_input(m, off)
break;
}
}
if (foundmship == 0)
goto docontinue;
if (foundmship == 0) {
INP_UNLOCK(inp);
continue;
}
}
#undef NMSHIPS
#undef MSHIP