[PATCH 1/2] nvmet-rdma: avoid circular locking dependency on install_queue()

[Hannes Reinecke <hare@suse.de>]

nvmet_rdma_install_queue() is driven from the ->io_work workqueue
function, but will call flush_workqueue() which might trigger
->release_work() which in itself calls flush_work on ->io_work.

To avoid that check for pending queue in disconnecting status,
and return 'controller busy' until all disconnects are completed.

Signed-off-by: Hannes Reinecke <hare@suse.de>
---
 drivers/nvme/target/rdma.c | 14 ++++++++++++--
 1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
index 4597bca43a6d..eaeb94a9e863 100644
--- a/drivers/nvme/target/rdma.c
+++ b/drivers/nvme/target/rdma.c
@@ -1583,8 +1583,18 @@ 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_wq);
+		struct nvmet_rdma_queue *q;
+		int pending = 0;
+
+		mutex_lock(&nvmet_rdma_queue_mutex);
+		list_for_each_entry(q, &nvmet_rdma_queue_list, queue_list) {
+			if (q->state == NVMET_RDMA_Q_DISCONNECTING)
+				pending++;
+		}
+		mutex_unlock(&nvmet_rdma_queue_mutex);
+		/* Retry for pending controller teardown */
+		if (pending)
+			return NVME_SC_CONNECT_CTRL_BUSY;
 	}
 
 	ret = nvmet_rdma_cm_accept(cm_id, queue, &event->param.conn);
-- 
2.35.3