Revert "nvmet-rdma: use a private workqueue for delete"

This reverts commit 2acf70ad.

The commit never really fixed the intended issue and caused all
kinds of other issues, including a use before initialization.
Suggested-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drivers/nvme/target/rdma.c

@@ -122,7 +122,6 @@ struct nvmet_rdma_device {
 	int			inline_page_count;
 };
 
-static struct workqueue_struct *nvmet_rdma_delete_wq;
 static bool nvmet_rdma_use_srq;
 module_param_named(use_srq, nvmet_rdma_use_srq, bool, 0444);
 MODULE_PARM_DESC(use_srq, "Use shared receive queue.");
@@ -1274,12 +1273,12 @@ static int nvmet_rdma_queue_connect(struct rdma_cm_id *cm_id,
 
 	if (queue->host_qid == 0) {
 		/* Let inflight controller teardown complete */
-		flush_workqueue(nvmet_rdma_delete_wq);
+		flush_scheduled_work();
 	}
 
 	ret = nvmet_rdma_cm_accept(cm_id, queue, &event->param.conn);
 	if (ret) {
-		queue_work(nvmet_rdma_delete_wq, &queue->release_work);
+		schedule_work(&queue->release_work);
 		/* Destroying rdma_cm id is not needed here */
 		return 0;
 	}
@@ -1344,7 +1343,7 @@ static void __nvmet_rdma_queue_disconnect(struct nvmet_rdma_queue *queue)
 
 	if (disconnect) {
 		rdma_disconnect(queue->cm_id);
-		queue_work(nvmet_rdma_delete_wq, &queue->release_work);
+		schedule_work(&queue->release_work);
 	}
 }
 
@@ -1374,7 +1373,7 @@ static void nvmet_rdma_queue_connect_fail(struct rdma_cm_id *cm_id,
 	mutex_unlock(&nvmet_rdma_queue_mutex);
 
 	pr_err("failed to connect queue %d\n", queue->idx);
-	queue_work(nvmet_rdma_delete_wq, &queue->release_work);
+	schedule_work(&queue->release_work);
 }
 
 /**
@@ -1656,17 +1655,8 @@ static int __init nvmet_rdma_init(void)
 	if (ret)
 		goto err_ib_client;
 
-	nvmet_rdma_delete_wq = alloc_workqueue("nvmet-rdma-delete-wq",
-			WQ_UNBOUND | WQ_MEM_RECLAIM | WQ_SYSFS, 0);
-	if (!nvmet_rdma_delete_wq) {
-		ret = -ENOMEM;
-		goto err_unreg_transport;
-	}
-
 	return 0;
 
-err_unreg_transport:
-	nvmet_unregister_transport(&nvmet_rdma_ops);
 err_ib_client:
 	ib_unregister_client(&nvmet_rdma_ib_client);
 	return ret;
@@ -1674,7 +1664,6 @@ static int __init nvmet_rdma_init(void)
 
 static void __exit nvmet_rdma_exit(void)
 {
-	destroy_workqueue(nvmet_rdma_delete_wq);
 	nvmet_unregister_transport(&nvmet_rdma_ops);
 	ib_unregister_client(&nvmet_rdma_ib_client);
 	WARN_ON_ONCE(!list_empty(&nvmet_rdma_queue_list));