Dynamically allocate the irq for vmbus.
Hyper-V delivers this interrupt on a
specific CPU and so mark the interrupt so
that it cannot be migrated to other CPUs.
Signed-off-by: K. Y. Srinivasan <kys at microsoft.com>
Signed-off-by: Haiyang Zhang <haiyangz at microsoft.com>
Signed-off-by: Hank Janssen <hjanssen at microsoft.com>
---
drivers/staging/hv/vmbus_drv.c | 72 +++++++++++++++++++++++++++++++---------
1 files changed, 56 insertions(+), 16 deletions(-)
diff --git a/drivers/staging/hv/vmbus_drv.c b/drivers/staging/hv/vmbus_drv.c
index 459c707..9806bac 100644
--- a/drivers/staging/hv/vmbus_drv.c
+++ b/drivers/staging/hv/vmbus_drv.c
@@ -36,9 +36,7 @@
#include "vmbus_private.h"
-/* FIXME! We need to do this dynamically for PIC and APIC system */
-#define VMBUS_IRQ 0x5
-#define VMBUS_IRQ_VECTOR IRQ5_VECTOR
+static int vmbus_irq;
/* Main vmbus driver data structure */
struct vmbus_driver_context {
@@ -57,6 +55,27 @@ struct vmbus_driver_context {
struct vm_device device_ctx;
};
+/*
+ * Find an un-used IRQ that the VMBUS can use. If none is available;
+ * return -EBUSY.
+ */
+static int vmbus_get_irq(void)
+{
+ unsigned int avail_irq_mask;
+ int irq = -EBUSY;
+
+ /*
+ * Pick the first unused interrupt. HyperV can
+ * interrupt us on any interrupt line we specify.
+ */
+
+ avail_irq_mask = probe_irq_on();
+ if (avail_irq_mask != 0)
+ irq = ffs(avail_irq_mask);
+ probe_irq_off(avail_irq_mask);
+ return irq;
+}
+
static int vmbus_match(struct device *device, struct device_driver *driver);
static int vmbus_probe(struct device *device);
static int vmbus_remove(struct device *device);
@@ -80,7 +99,6 @@ EXPORT_SYMBOL(vmbus_loglevel);
/* (ALL_MODULES << 16 | DEBUG_LVL_ENTEREXIT); */
/* (((VMBUS | VMBUS_DRV)<<16) | DEBUG_LVL_ENTEREXIT); */
-static int vmbus_irq = VMBUS_IRQ;
/* Set up per device attributes in /sys/bus/vmbus/devices/<bus device> */
static struct device_attribute vmbus_device_attrs[] = {
@@ -467,6 +485,7 @@ static int vmbus_bus_init(void)
struct vm_device *dev_ctx = &vmbus_drv.device_ctx;
int ret;
unsigned int vector;
+ bool irq_assigned = false;
DPRINT_INFO(VMBUS, "+++++++ HV Driver version = %s +++++++",
HV_DRV_VERSION);
@@ -517,20 +536,42 @@ static int vmbus_bus_init(void)
goto cleanup;
}
- /* Get the interrupt resource */
- ret = request_irq(vmbus_irq, vmbus_isr, IRQF_SAMPLE_RANDOM,
- driver->name, NULL);
-
- if (ret != 0) {
- DPRINT_ERR(VMBUS_DRV, "ERROR - Unable to request IRQ %d",
- vmbus_irq);
+ /*
+ * Get an unused interrupt line and register our handler.
+ * Since there is a window between getting an unused
+ * interrupt line and registering our handler, we close
+ * this window by repeating the sequence if we raced.
+ * This loop will terminate under the following conditions:
+ *
+ * 1) If we succeed in registering our handler OR
+ * 2) If there are no free interrupt lines for our use OR
+ * 3) request_irq fails for reasons other than an irq collision
+ */
+ while (!irq_assigned) {
+ vmbus_irq = vmbus_get_irq();
- bus_unregister(&vmbus_drv_ctx->bus);
+ if (vmbus_irq < 0) {
+ bus_unregister(&vmbus_drv_ctx->bus);
+ ret = -EBUSY;
+ goto cleanup;
+ }
- ret = -1;
- goto cleanup;
+ ret = request_irq(vmbus_irq, vmbus_isr, IRQF_NOBALANCING,
+ driver->name, NULL);
+ switch (ret) {
+ case -EBUSY:
+ /* We raced and lost; try again.*/
+ continue;
+ case 0:
+ irq_assigned = true;
+ break;
+ default:
+ /* Failed to request_irq; cleanup */
+ goto cleanup;
+ }
}
- vector = VMBUS_IRQ_VECTOR;
+
+ vector = IRQ0_VECTOR + vmbus_irq;
DPRINT_INFO(VMBUS_DRV, "irq 0x%x vector 0x%x", vmbus_irq, vector);
@@ -1117,7 +1158,6 @@ MODULE_DEVICE_TABLE(pci, microsoft_hv_pci_table);
MODULE_LICENSE("GPL");
MODULE_VERSION(HV_DRV_VERSION);
-module_param(vmbus_irq, int, S_IRUGO);
module_param(vmbus_loglevel, int, S_IRUGO);
module_init(vmbus_init);
--
1.5.5.6