vfio: factor out a vfio_group_find_or_alloc helper

Factor out a helper to find or allocate the vfio_group to reduce the
spagetthi code in vfio_register_group_dev a little.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20210924155705.4258-5-hch@lst.de
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 8bd4b0b96b94a399b6f73fefbd0f92a7aa7d99ad..2b2679c7126fdfc27c1f1fbfb6e0b05e2af7907f 100644 (file)
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -823,10 +823,39 @@ void vfio_uninit_group_dev(struct vfio_device *device)
 }
 EXPORT_SYMBOL_GPL(vfio_uninit_group_dev);
 
+struct vfio_group *vfio_group_find_or_alloc(struct device *dev)
+{
+       struct iommu_group *iommu_group;
+       struct vfio_group *group;
+
+       iommu_group = vfio_iommu_group_get(dev);
+       if (!iommu_group)
+               return ERR_PTR(-EINVAL);
+
+       /* a found vfio_group already holds a reference to the iommu_group */
+       group = vfio_group_get_from_iommu(iommu_group);
+       if (group)
+               goto out_put;
+
+       /* a newly created vfio_group keeps the reference. */
+       group = vfio_create_group(iommu_group);
+       if (IS_ERR(group))
+               goto out_remove;
+       return group;
+
+out_remove:
+#ifdef CONFIG_VFIO_NOIOMMU
+       if (iommu_group_get_iommudata(iommu_group) == &noiommu)
+               iommu_group_remove_device(dev);
+#endif
+out_put:
+       iommu_group_put(iommu_group);
+       return group;
+}
+
 int vfio_register_group_dev(struct vfio_device *device)
 {
        struct vfio_device *existing_device;
-       struct iommu_group *iommu_group;
        struct vfio_group *group;
 
        /*
@@ -836,36 +865,17 @@ int vfio_register_group_dev(struct vfio_device *device)
        if (!device->dev_set)
                vfio_assign_device_set(device, device);
 
-       iommu_group = vfio_iommu_group_get(device->dev);
-       if (!iommu_group)
-               return -EINVAL;
-
-       group = vfio_group_get_from_iommu(iommu_group);
-       if (!group) {
-               group = vfio_create_group(iommu_group);
-               if (IS_ERR(group)) {
-#ifdef CONFIG_VFIO_NOIOMMU
-                       if (iommu_group_get_iommudata(iommu_group) == &noiommu)
-                               iommu_group_remove_device(device->dev);
-#endif
-                       iommu_group_put(iommu_group);
-                       return PTR_ERR(group);
-               }
-       } else {
-               /*
-                * A found vfio_group already holds a reference to the
-                * iommu_group.  A created vfio_group keeps the reference.
-                */
-               iommu_group_put(iommu_group);
-       }
+       group = vfio_group_find_or_alloc(device->dev);
+       if (IS_ERR(group))
+               return PTR_ERR(group);
 
        existing_device = vfio_group_get_device(group, device->dev);
        if (existing_device) {
                dev_WARN(device->dev, "Device already exists on group %d\n",
-                        iommu_group_id(iommu_group));
+                        iommu_group_id(group->iommu_group));
                vfio_device_put(existing_device);
 #ifdef CONFIG_VFIO_NOIOMMU
-               if (iommu_group_get_iommudata(iommu_group) == &noiommu)
+               if (iommu_group_get_iommudata(group->iommu_group) == &noiommu)
                        iommu_group_remove_device(device->dev);
 #endif
                vfio_group_put(group);