svn commit: r185740 - head/sys/dev/pccbb
Warner Losh
imp at FreeBSD.org
Sun Dec 7 10:32:10 PST 2008
Author: imp
Date: Sun Dec 7 18:32:09 2008
New Revision: 185740
URL: http://svn.freebsd.org/changeset/base/185740
Log:
Use atomic_add_int rather than a simple ++ to ensure no cache races if
the power interrupt and init code waiting for the interrupt are
running on different CPUs. I haven't seen this make any real
difference, but I've also had some reports of odd behavior I can't
otherwise explain. It is an infrequent operation, and certainly
wouldn't hurt.
Modified:
head/sys/dev/pccbb/pccbb_pci.c
Modified: head/sys/dev/pccbb/pccbb_pci.c
==============================================================================
--- head/sys/dev/pccbb/pccbb_pci.c Sun Dec 7 13:25:06 2008 (r185739)
+++ head/sys/dev/pccbb/pccbb_pci.c Sun Dec 7 18:32:09 2008 (r185740)
@@ -730,7 +730,7 @@ cbb_pci_filt(void *arg)
if (sockevent & CBB_SOCKET_EVENT_POWER) {
cbb_clrb(sc, CBB_SOCKET_MASK, CBB_SOCKET_EVENT_POWER);
cbb_set(sc, CBB_SOCKET_EVENT, CBB_SOCKET_EVENT_POWER);
- sc->powerintr++;
+ atomic_add_int(&sc->powerintr, 1);
wakeup((void *)&sc->powerintr);
}
retval = FILTER_HANDLED;
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