gpu: drm: amd: amdkfd: Remove create_workqueue()

alloc_workqueue replaces deprecated create_workqueue().

kfd_process_wq is used for delay destruction. A work item embedded in kfd_process gets queued to kfd_process_wq and when it executes it destroys and frees the containing kfd_process and thus itself.

This requires a dedicated workqueue because a work item once queued, may get freed at any point of time and any external entity cannot flush the work item. So, in order to wait for such a work item, it needs to be put on a dedicated workqueue.

kfd_module_exit() calls kfd_process_destroy_wq which ensures that all pending work items are finished before the module is removed.

flush_workqueue is unnecessary since destroy_workqueue() itself calls drain_workqueue() which flushes repeatedly till the workqueue becomes empty.

Hence flush_workqueue has been removed.

---
 drivers/gpu/drm/amd/amdkfd/kfd_process.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

index ac00579..b21d3fc8 100644
@@ -63,13 +63,12 @@ static struct kfd_process *create_process(const struct task_struct *thread);
 void kfd_process_create_wq(void)
 {
 	if (!kfd_process_wq)
-		kfd_process_wq = create_workqueue("kfd_process_wq");
+		kfd_process_wq = alloc_workqueue("kfd_process_wq",0,0);
 }
 
 void kfd_process_destroy_wq(void)
 {
 	if (kfd_process_wq) {
-		flush_workqueue(kfd_process_wq);
 		destroy_workqueue(kfd_process_wq);
 		kfd_process_wq = NULL;
 	}

create_workqueue(NAME) maps to alloc_workqueue(NAME, WQ_MEM_RECLAIM, 1), so the change is effectively dropping WQ_MEM_RECLAIM and changing concurrency value from 1 to WQ_DFL_ACTIVE. It'd be nice to explain why these changes are safe and I think they're. It just needs explanations.

Other than that, Acked-by: Tejun Heo <[email protected]>

Thanks.

tejun
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