From 420eb554d5ee6daad743d8190383219f757dd66c Mon Sep 17 00:00:00 2001 From: Daniel De Graaf <dgdegra@tycho.nsa.gov> Date: Thu, 27 Oct 2011 17:58:47 -0400 Subject: xen/event: Add reference counting to event channels Event channels exposed to userspace by the evtchn module may be used by other modules in an asynchronous manner, which requires that reference counting be used to prevent the event channel from being closed before the signals are delivered. The reference count on new event channels defaults to -1 which indicates the event channel is not referenced outside the kernel; evtchn_get fails if called on such an event channel. The event channels made visible to userspace by evtchn have a normal reference count. Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> --- drivers/xen/evtchn.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/xen/evtchn.c') diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c index dbc13e94b61..b1f60a0c0be 100644 --- a/drivers/xen/evtchn.c +++ b/drivers/xen/evtchn.c @@ -268,7 +268,7 @@ static int evtchn_bind_to_user(struct per_user_data *u, int port) rc = bind_evtchn_to_irqhandler(port, evtchn_interrupt, IRQF_DISABLED, u->name, (void *)(unsigned long)port); if (rc >= 0) - rc = 0; + rc = evtchn_make_refcounted(port); return rc; } -- cgit v1.2.3-70-g09d2