nvme-rdma: fix possible free of a non-allocated async event buffer

If nvme_rdma_configure_admin_queue fails before we allocated
the async event buffer, we will falsly free it because
nvme_rdma_free_queue is freeing it. Fix it by allocating the buffer right
after nvme_rdma_alloc_queue and free it right before nvme_rdma_queue_free
to maintain orderly reverse cleanup sequence.
Reported-by: Israel Rukshin <israelr@mellanox.com>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Max Gurtovoy <maxg@mellanox.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>

drivers/nvme/host/rdma.c

@@ -560,12 +560,6 @@ static void nvme_rdma_free_queue(struct nvme_rdma_queue *queue)
 	if (!test_and_clear_bit(NVME_RDMA_Q_ALLOCATED, &queue->flags))
 		return;
 
-	if (nvme_rdma_queue_idx(queue) == 0) {
-		nvme_rdma_free_qe(queue->device->dev,
-			&queue->ctrl->async_event_sqe,
-			sizeof(struct nvme_command), DMA_TO_DEVICE);
-	}
-
 	nvme_rdma_destroy_queue_ib(queue);
 	rdma_destroy_id(queue->cm_id);
 }
@@ -739,6 +733,8 @@ static void nvme_rdma_destroy_admin_queue(struct nvme_rdma_ctrl *ctrl,
 		blk_cleanup_queue(ctrl->ctrl.admin_q);
 		nvme_rdma_free_tagset(&ctrl->ctrl, ctrl->ctrl.admin_tagset);
 	}
+	nvme_rdma_free_qe(ctrl->device->dev, &ctrl->async_event_sqe,
+		sizeof(struct nvme_command), DMA_TO_DEVICE);
 	nvme_rdma_free_queue(&ctrl->queues[0]);
 }
 
@@ -755,11 +751,16 @@ static int nvme_rdma_configure_admin_queue(struct nvme_rdma_ctrl *ctrl,
 
 	ctrl->max_fr_pages = nvme_rdma_get_max_fr_pages(ctrl->device->dev);
 
+	error = nvme_rdma_alloc_qe(ctrl->device->dev, &ctrl->async_event_sqe,
+			sizeof(struct nvme_command), DMA_TO_DEVICE);
+	if (error)
+		goto out_free_queue;
+
 	if (new) {
 		ctrl->ctrl.admin_tagset = nvme_rdma_alloc_tagset(&ctrl->ctrl, true);
 		if (IS_ERR(ctrl->ctrl.admin_tagset)) {
 			error = PTR_ERR(ctrl->ctrl.admin_tagset);
-			goto out_free_queue;
+			goto out_free_async_qe;
 		}
 
 		ctrl->ctrl.admin_q = blk_mq_init_queue(&ctrl->admin_tag_set);
@@ -795,12 +796,6 @@ static int nvme_rdma_configure_admin_queue(struct nvme_rdma_ctrl *ctrl,
 	if (error)
 		goto out_stop_queue;
 
-	error = nvme_rdma_alloc_qe(ctrl->queues[0].device->dev,
-			&ctrl->async_event_sqe, sizeof(struct nvme_command),
-			DMA_TO_DEVICE);
-	if (error)
-		goto out_stop_queue;
-
 	return 0;
 
 out_stop_queue:
@@ -811,6 +806,9 @@ static int nvme_rdma_configure_admin_queue(struct nvme_rdma_ctrl *ctrl,
 out_free_tagset:
 	if (new)
 		nvme_rdma_free_tagset(&ctrl->ctrl, ctrl->ctrl.admin_tagset);
+out_free_async_qe:
+	nvme_rdma_free_qe(ctrl->device->dev, &ctrl->async_event_sqe,
+		sizeof(struct nvme_command), DMA_TO_DEVICE);
 out_free_queue:
 	nvme_rdma_free_queue(&ctrl->queues[0]);
 	return error;