[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 <coh...@redhat.com>
Signed-off-by: Yan Zhao <yan.y.z...@intel.com>

---
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