vfio: grab vfio_device reference *before* exposing the sucker via fd_install()

It's not critical (anymore) since another thread closing the file will block
on ->device_lock before it gets to dropping the final reference, but it's
definitely cleaner that way...

Acked-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 2 insertions, 2 deletions

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 887ae43276bb..17830c9c7cc6 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1111,10 +1111,10 @@ static int vfio_group_get_device_fd(struct vfio_group *group, char *buf)
                  */
                 filep->f_mode |= (FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
 
-                fd_install(ret, filep);
-
                 vfio_device_get(device);
                 atomic_inc(&group->container_users);
+
+                fd_install(ret, filep);
                 break;
         }
         mutex_unlock(&group->device_lock);