[PATCH 23/28] Drivers: hv: Handle vmbus interrupts concurrently on all cpus

["K. Y. Srinivasan" <kys@microsoft.com>]

Vmbus interrupts are unique in that while the interrupt is delivered on a
given vector, these can be handled concurrently on different CPUs. Handle the
vmbus interrupts concurrently on all the CPUs.

Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
---
 drivers/hv/hv.c        |    2 +-
 drivers/hv/vmbus_drv.c |   21 +++++++++++++++++++++
 2 files changed, 22 insertions(+), 1 deletions(-)

diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
index 363532a..03e6a1e 100644
--- a/drivers/hv/hv.c
+++ b/drivers/hv/hv.c
@@ -335,7 +335,7 @@ void hv_synic_init(void *irqarg)
 	shared_sint.as_uint64 = 0;
 	shared_sint.vector = irq_vector; /* HV_SHARED_SINT_IDT_VECTOR + 0x20; */
 	shared_sint.masked = false;
-	shared_sint.auto_eoi = false;
+	shared_sint.auto_eoi = true;
 
 	wrmsrl(HV_X64_MSR_SINT0 + VMBUS_MESSAGE_SINT, shared_sint.as_uint64);
 
diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 6e4f857..e066d41 100644
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -33,6 +33,7 @@
 #include <acpi/acpi_bus.h>
 #include <linux/completion.h>
 #include <linux/hyperv.h>
+#include <linux/kernel_stat.h>
 #include <asm/hyperv.h>
 #include <asm/hypervisor.h>
 #include "hyperv_vmbus.h"
@@ -501,6 +502,19 @@ static irqreturn_t vmbus_isr(int irq, void *dev_id)
 }
 
 /*
+ * vmbus interrupt flow handler:
+ * vmbus interrupts can concurrently occur on multiple CPUs and
+ * can be handled concurrently.
+ */
+
+void vmbus_flow_handler(unsigned int irq, struct irq_desc *desc)
+{
+	kstat_incr_irqs_this_cpu(irq, desc);
+
+	desc->action->handler(irq, desc->action->dev_id);
+}
+
+/*
  * vmbus_bus_init -Main vmbus driver initialization routine.
  *
  * Here, we
@@ -535,6 +549,13 @@ static int vmbus_bus_init(int irq)
 		goto err_unregister;
 	}
 
+	/*
+	 * Vmbus interrupts can be handled concurrently on
+	 * different CPUs. Establish an appropriate interrupt flow
+	 * handler that can support this model.
+	 */
+	irq_set_handler(irq, vmbus_flow_handler);
+
 	vector = IRQ0_VECTOR + irq;
 
 	/*
-- 
1.7.4.1