[PATCH 3/4] Staging: hv: vmbus: Check for events before messages
K. Y. Srinivasan
kys at microsoft.com
Wed Aug 31 21:35:56 UTC 2011
The Windows team has informed us that on Windows guests on Hyper-V,
they check for events before messages. They also recommended that we do
the same. This patch addresses this.
Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz at microsoft.com>
---
drivers/staging/hv/vmbus_drv.c | 22 ++++++++++++++--------
1 files changed, 14 insertions(+), 8 deletions(-)
diff --git a/drivers/staging/hv/vmbus_drv.c b/drivers/staging/hv/vmbus_drv.c
index b5e06d6..cd43ddd 100644
--- a/drivers/staging/hv/vmbus_drv.c
+++ b/drivers/staging/hv/vmbus_drv.c
@@ -442,14 +442,11 @@ static irqreturn_t vmbus_isr(int irq, void *dev_id)
union hv_synic_event_flags *event;
bool handled = false;
- page_addr = hv_context.synic_message_page[cpu];
- msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
-
- /* Check if there are actual msgs to be process */
- if (msg->header.message_type != HVMSG_NONE) {
- handled = true;
- tasklet_schedule(&msg_dpc);
- }
+ /*
+ * Check for events before checking for messages. This is the order
+ * in which events and messages are checked in Windows guests on
+ * Hyper-V, and the Windows team suggested we do the same.
+ */
page_addr = hv_context.synic_event_page[cpu];
event = (union hv_synic_event_flags *)page_addr + VMBUS_MESSAGE_SINT;
@@ -460,6 +457,15 @@ static irqreturn_t vmbus_isr(int irq, void *dev_id)
tasklet_schedule(&event_dpc);
}
+ page_addr = hv_context.synic_message_page[cpu];
+ msg = (struct hv_message *)page_addr + VMBUS_MESSAGE_SINT;
+
+ /* Check if there are actual msgs to be processed */
+ if (msg->header.message_type != HVMSG_NONE) {
+ handled = true;
+ tasklet_schedule(&msg_dpc);
+ }
+
if (handled)
return IRQ_HANDLED;
else
--
1.7.4.1
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