[PATCH V1 1/2] drm/amdgpu/userq: avoid uneccessary locking in amdgpu_userq_create

[Sunil Khatri <sunil.khatri@amd.com>]

Reorganise code to avoid holding mutex userq_mutex while
also trying to grab exec lock ww_mutex where its not needed
for function amdgpu_userq_input_va_validate

Signed-off-by: Sunil Khatri <sunil.khatri@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c | 33 +++++++++++------------
 1 file changed, 15 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
index 3a6e7a569c78..3f502c18879a 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_userq.c
@@ -737,28 +737,17 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args)
 		return r;
 	}
 
-	/*
-	 * There could be a situation that we are creating a new queue while
-	 * the other queues under this UQ_mgr are suspended. So if there is any
-	 * resume work pending, wait for it to get done.
-	 *
-	 * This will also make sure we have a valid eviction fence ready to be used.
-	 */
-	amdgpu_userq_ensure_ev_fence(&fpriv->userq_mgr, &fpriv->evf_mgr);
-
 	uq_funcs = adev->userq_funcs[args->in.ip_type];
 	if (!uq_funcs) {
 		drm_file_err(uq_mgr->file, "Usermode queue is not supported for this IP (%u)\n",
 			     args->in.ip_type);
-		r = -EINVAL;
-		goto unlock;
+		return -EINVAL;
 	}
 
 	queue = kzalloc(sizeof(struct amdgpu_usermode_queue), GFP_KERNEL);
 	if (!queue) {
 		drm_file_err(uq_mgr->file, "Failed to allocate memory for queue\n");
-		r = -ENOMEM;
-		goto unlock;
+		return -ENOMEM;
 	}
 
 	INIT_LIST_HEAD(&queue->userq_va_list);
@@ -781,12 +770,21 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args)
 		goto free_queue;
 	}
 
+	/*
+	 * There could be a situation that we are creating a new queue while
+	 * the other queues under this UQ_mgr are suspended. So if there is any
+	 * resume work pending, wait for it to get done.
+	 *
+	 * This will also make sure we have a valid eviction fence ready to be used.
+	 */
+	amdgpu_userq_ensure_ev_fence(&fpriv->userq_mgr, &fpriv->evf_mgr);
+
 	/* Convert relative doorbell offset into absolute doorbell index */
 	index = amdgpu_userq_get_doorbell_index(uq_mgr, &db_info, filp);
 	if (index == (uint64_t)-EINVAL) {
 		drm_file_err(uq_mgr->file, "Failed to get doorbell for queue\n");
 		r = -EINVAL;
-		goto free_queue;
+		goto unlock;
 	}
 
 	queue->doorbell_index = index;
@@ -794,7 +792,7 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args)
 	r = amdgpu_userq_fence_driver_alloc(adev, &queue->fence_drv);
 	if (r) {
 		drm_file_err(uq_mgr->file, "Failed to alloc fence driver\n");
-		goto free_queue;
+		goto unlock;
 	}
 
 	r = uq_funcs->mqd_create(queue, &args->in);
@@ -858,11 +856,10 @@ amdgpu_userq_create(struct drm_file *filp, union drm_amdgpu_userq *args)
 	up_read(&adev->reset_domain->sem);
 clean_fence_driver:
 	amdgpu_userq_fence_driver_free(queue);
-free_queue:
-	kfree(queue);
 unlock:
 	mutex_unlock(&uq_mgr->userq_mutex);
-
+free_queue:
+	kfree(queue);
 	return r;
 }
 
-- 
2.34.1