[PATCH WIP/RFC v3 4/6] nvme-rdma: destroy nvme queue rdma resources on connect failure

[swise@opengridcomputing.com (Steve Wise)]

> After address resolution, the nvme_rdma_queue rdma resources are
> allocated.  If rdma route resolution or the connect fails, or the
> controller reconnect times out and gives up, then the rdma resources
> need to be freed.  Otherwise, rdma resources are leaked.
> 
> Reviewed-by: Christoph Hellwig <hch at lst.de>
> Reviewed-by: Sagi Grimberg <sagi at grimbrg.me>
> Signed-off-by: Steve Wise <swise at opengridcomputing.com>
> ---
>  drivers/nvme/host/rdma.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/nvme/host/rdma.c b/drivers/nvme/host/rdma.c
> index 8d22b95..c2f6cc6 100644
> --- a/drivers/nvme/host/rdma.c
> +++ b/drivers/nvme/host/rdma.c
> @@ -87,6 +87,7 @@ struct nvme_rdma_request {
> 
>  enum nvme_rdma_queue_flags {
>  	NVME_RDMA_Q_CONNECTED = (1 << 0),
> +	NVME_RDMA_IB_QUEUE_ALLOCATED = (1 << 1),
>  };
> 
>  struct nvme_rdma_queue {
> @@ -488,6 +489,8 @@ static void nvme_rdma_destroy_queue_ib(struct
> nvme_rdma_queue *queue)
>  	struct nvme_rdma_device *dev = queue->device;
>  	struct ib_device *ibdev = dev->dev;
> 
> +	if (!test_and_clear_bit(NVME_RDMA_IB_QUEUE_ALLOCATED, &queue-
> >flags))
> +		return;
>  	rdma_destroy_qp(queue->cm_id);
>  	ib_free_cq(queue->ib_cq);
> 
> @@ -538,6 +541,7 @@ static int nvme_rdma_create_queue_ib(struct
> nvme_rdma_queue *queue,
>  		ret = -ENOMEM;
>  		goto out_destroy_qp;
>  	}
> +	set_bit(NVME_RDMA_IB_QUEUE_ALLOCATED, &queue->flags);
> 
>  	return 0;
> 
> @@ -595,6 +599,8 @@ static int nvme_rdma_init_queue(struct nvme_rdma_ctrl
> *ctrl,
>  	return 0;
> 
>  out_destroy_cm_id:
> +	if (test_bit(NVME_RDMA_IB_QUEUE_ALLOCATED, &ctrl->queues[0].flags))
> +		nvme_rdma_destroy_queue_ib(queue);

I'm changing this to test_and_clear_bit() just to keep the ALLOCATED bit off
when there is no queue allocated.

Also, if nvme_rdma_init_queue() does detect a failure and destroy the cm_id and
queue, then the calling function, nvme_rdma_init_io_queues() must not try to
stop_and_free the queu that failed.  So I need this extra change:

@@ -659,7 +659,7 @@ static int nvme_rdma_init_io_queues(struct nvme_rdma_ctrl
*ctrl)
        return 0;

 out_free_queues:
-       for (; i >= 1; i--)
+       for (i--; i >= 1; i--)
                nvme_rdma_stop_and_free_queue(&ctrl->queues[i]);

I found this by forcing rdma rejects (accidentally :)).

Steve.