[PATCH 24/28] Drivers: hv: Add a check to deal with spurious interrupts

K. Y. Srinivasan
2012-12-01T14:28:56Z

We establish the handler before we have fully initialized the VMBUS state.
Deal with spurious interrupts.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
---
drivers/hv/vmbus_drv.c | 10 ++++++----
1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index e066d41..797142c 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -454,6 +454,12 @@ static irqreturn_t vmbus_isr(int irq, void *dev_id)
union hv_synic_event_flags *event;
bool handled = false;

+ page_addr = hv_context.synic_event_page[cpu];
+ if (page_addr == NULL)
+ return IRQ_NONE;
+
+ event = (union hv_synic_event_flags *)page_addr +
+ VMBUS_MESSAGE_SINT;
/*
* Check for events before checking for messages. This is the order
* in which events and messages are checked in Windows guests on
@@ -463,10 +469,6 @@ static irqreturn_t vmbus_isr(int irq, void *dev_id)
if ((vmbus_proto_version == VERSION_WS2008) ||
(vmbus_proto_version == VERSION_WIN7)) {

- page_addr = hv_context.synic_event_page[cpu];
- event = (union hv_synic_event_flags *)page_addr +
- VMBUS_MESSAGE_SINT;
-
/* Since we are a child, we only need to check bit 0 */
if (sync_test_and_clear_bit(0,
(unsigned long *) &event->flags32[0])) {
--
1.7.4.1