[PATCH] drivers/xen/evtchn.c: Check failure for evtchn_make_refcounted()

[Chen Gang <gang.chen.5i5j@gmail.com>]

evtchn_make_refcounted() may return failure, so need process the failure
case. In failure case, it need call unbind_from_irqhandler() just like
evtchn_unbind_from_user() has done.

irq_from_evtchn() must be OK when bind_evtchn_to_irqhandler() succeed,
so need not check it again.

Also still need remain the closing port code, because when the failure
occurs, unbind_from_irqhandler() will not close port internally.


Signed-off-by: Chen Gang <gang.chen.5i5j@gmail.com>
---
 drivers/xen/evtchn.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
index 00f40f0..8a629d6 100644
--- a/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@ -311,6 +311,11 @@ static int evtchn_bind_to_user(struct per_user_data *u, int port)
 		goto err;
 
 	rc = evtchn_make_refcounted(port);
+	if (rc < 0) {
+		unbind_from_irqhandler(irq_from_evtchn(port), evtchn);
+		goto err;
+	}
+
 	return rc;
 
 err:
-- 
1.7.11.7