[PATCH v9 03/12] vfio: Rearrange functions to get vfio_group from dev

[Kirti Wankhede <kwankhede@nvidia.com>]

Rearrange functions to have common function to increment container_users.

Signed-off-by: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Neo Jia <cjia@nvidia.com>
Change-Id: I1f93262bdbab75094bc24b087b29da35ba70c4c6
---
 drivers/vfio/vfio.c | 57 ++++++++++++++++++++++++++++++++++-------------------
 1 file changed, 37 insertions(+), 20 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index d1d70e0b011b..2e83bdf007fe 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -480,6 +480,21 @@ static struct vfio_group *vfio_group_get_from_minor(int minor)
 	return group;
 }
 
+static struct vfio_group *vfio_group_get_from_dev(struct device *dev)
+{
+	struct iommu_group *iommu_group;
+	struct vfio_group *group;
+
+	iommu_group = iommu_group_get(dev);
+	if (!iommu_group)
+		return NULL;
+
+	group = vfio_group_get_from_iommu(iommu_group);
+	iommu_group_put(iommu_group);
+
+	return group;
+}
+
 /**
  * Device objects - create, release, get, put, search
  */
@@ -811,16 +826,10 @@ EXPORT_SYMBOL_GPL(vfio_add_group_dev);
  */
 struct vfio_device *vfio_device_get_from_dev(struct device *dev)
 {
-	struct iommu_group *iommu_group;
 	struct vfio_group *group;
 	struct vfio_device *device;
 
-	iommu_group = iommu_group_get(dev);
-	if (!iommu_group)
-		return NULL;
-
-	group = vfio_group_get_from_iommu(iommu_group);
-	iommu_group_put(iommu_group);
+	group = vfio_group_get_from_dev(dev);
 	if (!group)
 		return NULL;
 
@@ -1376,6 +1385,23 @@ static bool vfio_group_viable(struct vfio_group *group)
 					 group, vfio_dev_viable) == 0);
 }
 
+static int vfio_group_add_container_user(struct vfio_group *group)
+{
+	if (!atomic_inc_not_zero(&group->container_users))
+		return -EINVAL;
+
+	if (group->noiommu) {
+		atomic_dec(&group->container_users);
+		return -EPERM;
+	}
+	if (!group->container->iommu_driver || !vfio_group_viable(group)) {
+		atomic_dec(&group->container_users);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
 static const struct file_operations vfio_device_fops;
 
 static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
@@ -1685,23 +1711,14 @@ static const struct file_operations vfio_device_fops = {
 struct vfio_group *vfio_group_get_external_user(struct file *filep)
 {
 	struct vfio_group *group = filep->private_data;
+	int ret;
 
 	if (filep->f_op != &vfio_group_fops)
 		return ERR_PTR(-EINVAL);
 
-	if (!atomic_inc_not_zero(&group->container_users))
-		return ERR_PTR(-EINVAL);
-
-	if (group->noiommu) {
-		atomic_dec(&group->container_users);
-		return ERR_PTR(-EPERM);
-	}
-
-	if (!group->container->iommu_driver ||
-			!vfio_group_viable(group)) {
-		atomic_dec(&group->container_users);
-		return ERR_PTR(-EINVAL);
-	}
+	ret = vfio_group_add_container_user(group);
+	if (ret)
+		return ERR_PTR(ret);
 
 	vfio_group_get(group);
 
-- 
2.7.0