vfio: put off the allocation of "minor" in vfio_create_group

The next code fragment "list_for_each_entry" is not depend on "minor". With this
patch, the free of "minor" in "list_for_each_entry" can be reduced, and there is
no functional change.

Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 6 insertions, 7 deletions

diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 23ba12afe01f..86aac7e4a050 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -234,22 +234,21 @@ static struct vfio_group *vfio_create_group(struct iommu_group *iommu_group)
 
         mutex_lock(&vfio.group_lock);
 
-        minor = vfio_alloc_group_minor(group);
-        if (minor < 0) {
-                vfio_group_unlock_and_free(group);
-                return ERR_PTR(minor);
-        }
-
         /* Did we race creating this group? */
         list_for_each_entry(tmp, &vfio.group_list, vfio_next) {
                 if (tmp->iommu_group == iommu_group) {
                         vfio_group_get(tmp);
-                        vfio_free_group_minor(minor);
                         vfio_group_unlock_and_free(group);
                         return tmp;
                 }
         }
 
+        minor = vfio_alloc_group_minor(group);
+        if (minor < 0) {
+                vfio_group_unlock_and_free(group);
+                return ERR_PTR(minor);
+        }
+
         dev = device_create(vfio.class, NULL,
                             MKDEV(MAJOR(vfio.group_devt), minor),
                             group, "%d", iommu_group_id(iommu_group));