From 3e7d0bebac143f9852853b0c419e8f4347f30de7 Mon Sep 17 00:00:00 2001 From: Warner Losh Date: Sun, 7 Dec 2008 18:32:09 +0000 Subject: [PATCH] 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. --- sys/dev/pccbb/pccbb_pci.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/sys/dev/pccbb/pccbb_pci.c b/sys/dev/pccbb/pccbb_pci.c index 5d389213c882..8c64ef786a72 100644 --- a/sys/dev/pccbb/pccbb_pci.c +++ b/sys/dev/pccbb/pccbb_pci.c @@ -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;