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[Qemu-devel] [PATCH v3 1/3] VFIO: Wrapper for getting reference to vfio_


From: Pandarathil, Vijaymohan R
Subject: [Qemu-devel] [PATCH v3 1/3] VFIO: Wrapper for getting reference to vfio_device from device
Date: Sun, 3 Feb 2013 14:10:13 +0000

        - Added vfio_device_get_from_dev() as wrapper to get
          reference to vfio_device from struct device.

        - Added vfio_device_data() as a wrapper to get device_data from
          vfio_device.

Signed-off-by: Vijay Mohan Pandarathil <address@hidden>
---
 drivers/vfio/vfio.c  | 41 ++++++++++++++++++++++++++++++++---------
 include/linux/vfio.h |  3 +++
 2 files changed, 35 insertions(+), 9 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 12c264d..f0a78a2 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -407,12 +407,13 @@ static void vfio_device_release(struct kref *kref)
 }
 
 /* Device reference always implies a group reference */
-static void vfio_device_put(struct vfio_device *device)
+void vfio_device_put(struct vfio_device *device)
 {
        struct vfio_group *group = device->group;
        kref_put_mutex(&device->kref, vfio_device_release, &group->device_lock);
        vfio_group_put(group);
 }
+EXPORT_SYMBOL_GPL(vfio_device_put);
 
 static void vfio_device_get(struct vfio_device *device)
 {
@@ -642,8 +643,12 @@ int vfio_add_group_dev(struct device *dev,
 }
 EXPORT_SYMBOL_GPL(vfio_add_group_dev);
 
-/* Test whether a struct device is present in our tracking */
-static bool vfio_dev_present(struct device *dev)
+/**
+ * This does a get on the vfio_device from device.
+ * Callers of this function will have to call vfio_put_device() to
+ * remove the reference.
+ */
+struct vfio_device *vfio_device_get_from_dev(struct device *dev)
 {
        struct iommu_group *iommu_group;
        struct vfio_group *group;
@@ -651,25 +656,43 @@ static bool vfio_dev_present(struct device *dev)
 
        iommu_group = iommu_group_get(dev);
        if (!iommu_group)
-               return false;
+               return NULL;
 
        group = vfio_group_get_from_iommu(iommu_group);
        if (!group) {
                iommu_group_put(iommu_group);
-               return false;
+               return NULL;
        }
 
        device = vfio_group_get_device(group, dev);
        if (!device) {
                vfio_group_put(group);
                iommu_group_put(iommu_group);
-               return false;
+               return NULL;
        }
-
-       vfio_device_put(device);
        vfio_group_put(group);
        iommu_group_put(iommu_group);
-       return true;
+       return device;
+}
+EXPORT_SYMBOL_GPL(vfio_device_get_from_dev);
+
+void *vfio_device_data(struct vfio_device *device)
+{
+       return device->device_data;
+}
+EXPORT_SYMBOL_GPL(vfio_device_data);
+
+/* Test whether a struct device is present in our tracking */
+static bool vfio_dev_present(struct device *dev)
+{
+       struct vfio_device *device;
+
+       device = vfio_device_get_from_dev(dev);
+       if (device) {
+               vfio_device_put(device);
+               return true;
+       } else
+               return false;
 }
 
 /*
diff --git a/include/linux/vfio.h b/include/linux/vfio.h
index ab9e862..ac8d488 100644
--- a/include/linux/vfio.h
+++ b/include/linux/vfio.h
@@ -45,6 +45,9 @@ extern int vfio_add_group_dev(struct device *dev,
                              void *device_data);
 
 extern void *vfio_del_group_dev(struct device *dev);
+extern struct vfio_device *vfio_device_get_from_dev(struct device *dev);
+extern void vfio_device_put(struct vfio_device *device);
+extern void *vfio_device_data(struct vfio_device *device);
 
 /**
  * struct vfio_iommu_driver_ops - VFIO IOMMU driver callbacks
-- 
1.7.11.3




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