From 7341d908af307a34098a9da52f49037d815c868f Mon Sep 17 00:00:00 2001 From: "K. Y. Srinivasan" Date: Wed, 31 Aug 2011 14:35:56 -0700 Subject: [PATCH] Staging: hv: vmbus: Check for events before messages 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 Signed-off-by: Haiyang Zhang Signed-off-by: Greg Kroah-Hartman --- drivers/staging/hv/vmbus_drv.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) diff --git a/drivers/staging/hv/vmbus_drv.c b/drivers/staging/hv/vmbus_drv.c index b5e06d68f058..cd43ddd3cc83 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