[Qemu-devel] [PATCH v11 12/22] vfio: Add notifier callback to parent's ops structure of mdev

[Kirti Wankhede]

Add a notifier calback to parent's ops structure of mdev device so that per
device notifer for vfio module is registered through vfio_mdev module.

Signed-off-by: Kirti Wankhede <kwankh...@nvidia.com>
Signed-off-by: Neo Jia <c...@nvidia.com>
Change-Id: Iafa6f1721aecdd6e50eb93b153b5621e6d29b637
---
 drivers/vfio/mdev/vfio_mdev.c | 19 +++++++++++++++++++
 include/linux/mdev.h          |  9 +++++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index bb534d19e321..2b7c24aa9e46 100644
--- a/drivers/vfio/mdev/vfio_mdev.c
+++ b/drivers/vfio/mdev/vfio_mdev.c
@@ -24,6 +24,15 @@
 #define DRIVER_AUTHOR   "NVIDIA Corporation"
 #define DRIVER_DESC     "VFIO based driver for Mediated device"
 
+static int vfio_mdev_notifier(struct notifier_block *nb, unsigned long action,
+                             void *data)
+{
+       struct mdev_device *mdev = container_of(nb, struct mdev_device, nb);
+       struct parent_device *parent = mdev->parent;
+
+       return parent->ops->notifier(mdev, action, data);
+}
+
 static int vfio_mdev_open(void *device_data)
 {
        struct mdev_device *mdev = device_data;
@@ -40,6 +49,11 @@ static int vfio_mdev_open(void *device_data)
        if (ret)
                module_put(THIS_MODULE);
 
+       if (likely(parent->ops->notifier)) {
+               mdev->nb.notifier_call = vfio_mdev_notifier;
+               if (vfio_register_notifier(&mdev->dev, &mdev->nb))
+                       pr_err("Failed to register notifier for mdev\n");
+       }
        return ret;
 }
 
@@ -48,6 +62,11 @@ static void vfio_mdev_release(void *device_data)
        struct mdev_device *mdev = device_data;
        struct parent_device *parent = mdev->parent;
 
+       if (likely(parent->ops->notifier)) {
+               if (vfio_unregister_notifier(&mdev->dev, &mdev->nb))
+                       pr_err("Failed to unregister notifier for mdev\n");
+       }
+
        if (likely(parent->ops->release))
                parent->ops->release(mdev);
 
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index 0352febc1944..2999ef0ddaed 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -37,6 +37,7 @@ struct mdev_device {
        struct kref             ref;
        struct list_head        next;
        struct kobject          *type_kobj;
+       struct notifier_block   nb;
 };
 
 
@@ -84,6 +85,12 @@ struct mdev_device {
  *                     @cmd: mediated device structure
  *                     @arg: mediated device structure
  * @mmap:              mmap callback
+ *                     @mdev: mediated device structure
+ *                     @vma: vma structure
+ * @notifer:           Notifier callback
+ *                     @mdev: mediated device structure
+ *                     @action: Action for which notifier is called
+ *                     @data: Data associated with the notifier
  * Parent device that support mediated device should be registered with mdev
  * module with parent_ops structure.
  **/
@@ -105,6 +112,8 @@ struct parent_ops {
        ssize_t (*ioctl)(struct mdev_device *mdev, unsigned int cmd,
                         unsigned long arg);
        int     (*mmap)(struct mdev_device *mdev, struct vm_area_struct *vma);
+       int     (*notifier)(struct mdev_device *mdev, unsigned long action,
+                           void *data);
 };
 
 /* interface for exporting mdev supported type attributes */
-- 
2.7.0