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Relax locking of carp_forus().

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This fixes deadlock between CARP and bridge.  Bridge calls this function
taking CARP lock while holding bridge lock.  Same time CARP tries to send
its announcements via the bridge while holding CARP lock.

Use of CARP_LOCK() here does not solve anything, since sc_addr is constant
while race on sc_state is harmless and use of the lock does not close it.

Reviewed by:	glebius
MFC after:	2 weeks
Sponsored by:	iXsystems, Inc.
This commit is contained in:
Alexander Motin 2019-12-31 18:58:29 +00:00
parent d930203192
commit 8c3fbf3c20
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=356240
1 changed files with 4 additions and 3 deletions
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7
sys/netinet/ip_carp.c
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@ -1230,14 +1230,15 @@ carp_forus(struct ifnet *ifp, u_char *dhost)
CIF_LOCK(ifp->if_carp);
IFNET_FOREACH_CARP(ifp, sc) {
CARP_LOCK(sc);
/*
* CARP_LOCK() is not here, since would protect nothing, but
* cause deadlock with if_bridge, calling this under its lock.
*/
if (sc->sc_state == MASTER && !bcmp(dhost, LLADDR(&sc->sc_addr),
ETHER_ADDR_LEN)) {
CARP_UNLOCK(sc);
CIF_UNLOCK(ifp->if_carp);
return (1);
}
CARP_UNLOCK(sc);
}
CIF_UNLOCK(ifp->if_carp);