[PATCH 6/6] drm/amdkfd: Fix sdma queue allocate race condition

[Zeng, Oak]

SDMA queue allocation requires the dqm lock at it modify
the global dqm members. Move up the dqm_lock so sdma
queue allocation is enclosed in the critical section. Move
mqd allocation out of critical section to avoid circular
lock dependency.

Change-Id: I96abd42eae6e77c82a5ba1b8e600af3efe8d791d
Signed-off-by: Oak Zeng <Oak.Zeng at amd.com>
---
 .../gpu/drm/amd/amdkfd/kfd_device_queue_manager.c  | 24 +++++++++++-----------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
index 166636c..cd259b8 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_device_queue_manager.c
@@ -1133,23 +1133,27 @@ static int create_queue_cpsch(struct device_queue_manager *dqm, struct queue *q,
 	if (dqm->total_queue_count >= max_num_of_queues_per_device) {
 		pr_warn("Can't create new usermode queue because %d queues were already created\n",
 				dqm->total_queue_count);
-		retval = -EPERM;
-		goto out;
+		return -EPERM;
 	}
 
+	mqd_mgr = dqm->mqd_mgrs[get_mqd_type_from_queue_type(
+			q->properties.type)];
+	q->mqd_mem_obj = mqd_mgr->allocate_mqd(mqd_mgr->dev, &q->properties);
+	if (!q->mqd_mem_obj)
+		return -ENOMEM;
+
+	dqm_lock(dqm);
 	if (q->properties.type == KFD_QUEUE_TYPE_SDMA ||
 		q->properties.type == KFD_QUEUE_TYPE_SDMA_XGMI) {
 		retval = allocate_sdma_queue(dqm, q);
 		if (retval)
-			goto out;
+			goto out_unlock;
 	}
 
 	retval = allocate_doorbell(qpd, q);
 	if (retval)
 		goto out_deallocate_sdma_queue;
 
-	mqd_mgr = dqm->mqd_mgrs[get_mqd_type_from_queue_type(
-			q->properties.type)];
 	/*
 	 * Eviction state logic: mark all queues as evicted, even ones
 	 * not currently active. Restoring inactive queues later only
@@ -1161,12 +1165,8 @@ static int create_queue_cpsch(struct device_queue_manager *dqm, struct queue *q,
 		dqm->asic_ops.init_sdma_vm(dqm, q, qpd);
 	q->properties.tba_addr = qpd->tba_addr;
 	q->properties.tma_addr = qpd->tma_addr;
-	q->mqd_mem_obj = mqd_mgr->allocate_mqd(mqd_mgr->dev, &q->properties);
-	if (!q->mqd_mem_obj)
-		goto out_deallocate_doorbell;
 	mqd_mgr->init_mqd(mqd_mgr, &q->mqd, q->mqd_mem_obj,
 				&q->gart_mqd_addr, &q->properties);
-	dqm_lock(dqm);
 
 	list_add(&q->list, &qpd->queues_list);
 	qpd->queue_count++;
@@ -1192,13 +1192,13 @@ static int create_queue_cpsch(struct device_queue_manager *dqm, struct queue *q,
 	dqm_unlock(dqm);
 	return retval;
 
-out_deallocate_doorbell:
-	deallocate_doorbell(qpd, q);
 out_deallocate_sdma_queue:
 	if (q->properties.type == KFD_QUEUE_TYPE_SDMA ||
 		q->properties.type == KFD_QUEUE_TYPE_SDMA_XGMI)
 		deallocate_sdma_queue(dqm, q);
-out:
+out_unlock:
+	dqm_unlock(dqm);
+	mqd_mgr->free_mqd(mqd_mgr, q->mqd, q->mqd_mem_obj);
 	return retval;
 }
 
-- 
2.7.4