[Qemu-devel] [PATCH v13 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 <address@hidden>
Signed-off-by: Neo Jia <address@hidden>
Change-Id: Iafa6f1721aecdd6e50eb93b153b5621e6d29b637
---
 drivers/vfio/mdev/vfio_mdev.c | 25 ++++++++++++++++++++++++-
 include/linux/mdev.h          |  9 +++++++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/drivers/vfio/mdev/vfio_mdev.c b/drivers/vfio/mdev/vfio_mdev.c
index ffc36758cb84..4fc63db38829 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;
@@ -36,9 +45,18 @@ static int vfio_mdev_open(void *device_data)
        if (!try_module_get(THIS_MODULE))
                return -ENODEV;
 
+       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");
+       }
+
        ret = parent->ops->open(mdev);
-       if (ret)
+       if (ret) {
+               if (likely(parent->ops->notifier))
+                       vfio_unregister_notifier(&mdev->dev, &mdev->nb);
                module_put(THIS_MODULE);
+       }
 
        return ret;
 }
@@ -51,6 +69,11 @@ static void vfio_mdev_release(void *device_data)
        if (likely(parent->ops->release))
                parent->ops->release(mdev);
 
+       if (likely(parent->ops->notifier)) {
+               if (vfio_unregister_notifier(&mdev->dev, &mdev->nb))
+                       pr_err("Failed to unregister notifier for mdev\n");
+       }
+
        module_put(THIS_MODULE);
 }
 
diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index ec819e9a115a..94c43034c297 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;
 };
 
 /**
@@ -85,6 +86,12 @@ struct mdev_device {
  * @mmap:              mmap callback
  *                     @mdev: mediated device structure
  *                     @vma: vma structure
+ * @notifer:           Notifier callback, currently only for
+ *                     VFIO_IOMMU_NOTIFY_DMA_UNMAP action notified duing
+ *                     DMA_UNMAP call on mapped iova range.
+ *                     @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.
  **/
@@ -106,6 +113,8 @@ 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