[PATCH v2] vfio: fix a missed vfio group put in vfio_pin_pages

[Yan Zhao]

when error occurs, need to put vfio group after a successful get.

Fixes: 95fc87b44104 ("vfio: Selective dirty page tracking if IOMMU backed device pins pages")

Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>

---
v2: updated the format of the Fixes: line. (Cornelia)
---
 drivers/vfio/vfio.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 262ab0efd06c..5e6e0511b5aa 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1949,8 +1949,10 @@ int vfio_pin_pages(struct device *dev, unsigned long *user_pfn, int npage,
 	if (!group)
 		return -ENODEV;
 
-	if (group->dev_counter > 1)
-		return -EINVAL;
+	if (group->dev_counter > 1) {
+		ret = -EINVAL;
+		goto err_pin_pages;
+	}
 
 	ret = vfio_group_add_container_user(group);
 	if (ret)
-- 
2.17.1