[PATCH] drm/amdgpu: test uq_mgr list before add it to userq_mgr_list

[Prike Liang]

This test will avoid to add the uq_mgr duplicated list to
the userq_mgr_list.

Fixes: 4ed9e48f0821 ("drm/amdgpu: store userq_managers in a list in adev")
Signed-off-by: Prike Liang <prike.li...@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c 
b/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
index b661b0474409..5d533d66de85 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userqueue.c
@@ -366,7 +366,8 @@ amdgpu_userqueue_create(struct drm_file *filp, union 
drm_amdgpu_userq *args)
        }
        args->out.queue_id = qid;
        mutex_lock(&adev->userq_mutex);
-       list_add(&uq_mgr->list, &adev->userq_mgr_list);
+       if (list_empty(&uq_mgr->list))
+               list_add(&uq_mgr->list, &adev->userq_mgr_list);
        mutex_unlock(&adev->userq_mutex);
 
 unlock:
-- 
2.34.1