nvme-rdma: cancel async events before freeing event struct

Cancel async event work in case async event has been queued up, and
nvme_rdma_submit_async_event() runs after event has been freed.
Signed-off-by: David Milburn <dmilburn@redhat.com>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/rdma.c

@@ -835,6 +835,7 @@ static void nvme_rdma_destroy_admin_queue(struct nvme_rdma_ctrl *ctrl,
 		blk_mq_free_tag_set(ctrl->ctrl.admin_tagset);
 	}
 	if (ctrl->async_event_sqe.data) {
+		cancel_work_sync(&ctrl->ctrl.async_event_work);
 		nvme_rdma_free_qe(ctrl->device->dev, &ctrl->async_event_sqe,
 				sizeof(struct nvme_command), DMA_TO_DEVICE);
 		ctrl->async_event_sqe.data = NULL;