[PATCH V2 3/6] vDPA: implement IRQ offloading helpers in vDPA core

[Zhu Lingshan]

This commit implements IRQ offloading helpers in vDPA core by
introducing two couple of functions:

vdpa_alloc_vq_irq() and vdpa_free_vq_irq(): request irq and free
irq, will setup irq offloading.

vdpa_setup_irq() and vdpa_unsetup_irq(): supportive functions,
will call vhost_vdpa helpers.

Signed-off-by: Zhu Lingshan <lingshan....@intel.com>
Suggested-by: Jason Wang <jasow...@redhat.com>
---
 drivers/vdpa/vdpa.c  | 42 ++++++++++++++++++++++++++++++++++++++++++
 include/linux/vdpa.h | 13 +++++++++++++
 2 files changed, 55 insertions(+)

diff --git a/drivers/vdpa/vdpa.c b/drivers/vdpa/vdpa.c
index ff6562f..cce4d91 100644
--- a/drivers/vdpa/vdpa.c
+++ b/drivers/vdpa/vdpa.c
@@ -163,6 +163,48 @@ void vdpa_unregister_driver(struct vdpa_driver *drv)
 }
 EXPORT_SYMBOL_GPL(vdpa_unregister_driver);
 
+static void vdpa_setup_irq(struct vdpa_device *vdev, int qid, int irq)
+{
+       struct vdpa_driver *drv = drv_to_vdpa(vdev->dev.driver);
+
+       if (drv->setup_vq_irq)
+               drv->setup_vq_irq(vdev, qid, irq);
+}
+
+static void vdpa_unsetup_irq(struct vdpa_device *vdev, int qid)
+{
+       struct vdpa_driver *drv = drv_to_vdpa(vdev->dev.driver);
+
+       if (drv->unsetup_vq_irq)
+               drv->unsetup_vq_irq(vdev, qid);
+}
+
+int vdpa_alloc_vq_irq(struct device *dev, struct vdpa_device *vdev,
+                     unsigned int irq, irq_handler_t handler,
+                     unsigned long irqflags, const char *devname, void *dev_id,
+                     int qid)
+{
+       int ret;
+
+       ret = devm_request_irq(dev, irq, handler, irqflags, devname, dev_id);
+       if (ret)
+               dev_err(dev, "Failed to request irq for vq %d\n", qid);
+       else
+               vdpa_setup_irq(vdev, qid, irq);
+
+       return ret;
+
+}
+EXPORT_SYMBOL_GPL(vdpa_alloc_vq_irq);
+
+void vdpa_free_vq_irq(struct device *dev, struct vdpa_device *vdev, int irq,
+                        int qid, void *dev_id)
+{
+       devm_free_irq(dev, irq, dev_id);
+       vdpa_unsetup_irq(vdev, qid);
+}
+EXPORT_SYMBOL_GPL(vdpa_free_vq_irq);
+
 static int vdpa_init(void)
 {
        return bus_register(&vdpa_bus);
diff --git a/include/linux/vdpa.h b/include/linux/vdpa.h
index 239db79..7d64d83 100644
--- a/include/linux/vdpa.h
+++ b/include/linux/vdpa.h
@@ -220,17 +220,30 @@ struct vdpa_device *__vdpa_alloc_device(struct device 
*parent,
 
 int vdpa_register_device(struct vdpa_device *vdev);
 void vdpa_unregister_device(struct vdpa_device *vdev);
+/* request irq for a vq, setup irq offloading if its a vhost_vdpa vq */
+int vdpa_alloc_vq_irq(struct device *dev, struct vdpa_device *vdev,
+                     unsigned int irq, irq_handler_t handler,
+                     unsigned long irqflags, const char *devname, void *dev_id,
+                     int qid);
+/* free irq for a vq, unsetup irq offloading if its a vhost_vdpa vq */
+void vdpa_free_vq_irq(struct device *dev, struct vdpa_device *vdev, int irq,
+                     int qid, void *dev_id);
+
 
 /**
  * vdpa_driver - operations for a vDPA driver
  * @driver: underlying device driver
  * @probe: the function to call when a device is found.  Returns 0 or -errno.
  * @remove: the function to call when a device is removed.
+ * @setup_vq_irq: setup irq offloading for a vhost_vdpa vq.
+ * @unsetup_vq_irq: unsetup offloading for a vhost_vdpa vq.
  */
 struct vdpa_driver {
        struct device_driver driver;
        int (*probe)(struct vdpa_device *vdev);
        void (*remove)(struct vdpa_device *vdev);
+       void (*setup_vq_irq)(struct vdpa_device *vdev, int qid, int irq);
+       void (*unsetup_vq_irq)(struct vdpa_device *vdev, int qid);
 };
 
 #define vdpa_register_driver(drv) \
-- 
1.8.3.1