[PATCHv3] nvmet-rdma: Fix missing dma sync to nvme data structures

[hch@lst.de (Christoph Hellwig)]

On Wed, Jan 18, 2017@06:22:26PM -0600, Parav Pandit wrote:
> This patch performs dma sync operations on nvme_command
> and nvme_completion.
> 
> nvme_command is synced
> (a) on receiving of the recv queue completion for cpu access.
> (b) before posting recv wqe back to rdma adapter for device access.
> 
> nvme_completion is synced
> (a) on receiving of the recv queue completion of associated
> nvme_command for cpu access.
> (b) before posting send wqe to rdma adapter for device access.
> 
> This patch is generated for git://git.infradead.org/nvme-fabrics.git
> Branch: nvmf-4.10
> 
> Signed-off-by: Parav Pandit <parav at mellanox.com>
> Reviewed-by: Max Gurtovoy <maxg at mellanox.com>
> ---
>  drivers/nvme/target/rdma.c | 16 ++++++++++++++++
>  1 file changed, 16 insertions(+)
> 
> diff --git a/drivers/nvme/target/rdma.c b/drivers/nvme/target/rdma.c
> index 6c1c368..0599217 100644
> --- a/drivers/nvme/target/rdma.c
> +++ b/drivers/nvme/target/rdma.c
> @@ -438,6 +438,10 @@ static int nvmet_rdma_post_recv(struct nvmet_rdma_device *ndev,
>  {
>  	struct ib_recv_wr *bad_wr;
>  
> +	ib_dma_sync_single_for_device(ndev->device,
> +		cmd->sge[0].addr, cmd->sge[0].length,
> +		DMA_FROM_DEVICE);
> +
>  	if (ndev->srq)
>  		return ib_post_srq_recv(ndev->srq, &cmd->wr, &bad_wr);
>  	return ib_post_recv(cmd->queue->cm_id->qp, &cmd->wr, &bad_wr);
> @@ -538,6 +542,11 @@ static void nvmet_rdma_queue_response(struct nvmet_req *req)
>  		first_wr = &rsp->send_wr;
>  
>  	nvmet_rdma_post_recv(rsp->queue->dev, rsp->cmd);
> +
> +	ib_dma_sync_single_for_device(rsp->queue->dev->device,
> +			rsp->send_sge.addr, rsp->send_sge.length,
> +			DMA_TO_DEVICE);
> +
>  	if (ib_post_send(cm_id->qp, first_wr, &bad_wr)) {
>  		pr_err("sending cmd response failed\n");
>  		nvmet_rdma_release_rsp(rsp);
> @@ -698,6 +707,13 @@ static void nvmet_rdma_handle_command(struct nvmet_rdma_queue *queue,
>  	cmd->n_rdma = 0;
>  	cmd->req.port = queue->port;
>  
> +	ib_dma_sync_single_for_cpu(queue->dev->device,
> +		cmd->cmd->sge[0].addr, cmd->cmd->sge[0].length,
> +		DMA_FROM_DEVICE);
> +	ib_dma_sync_single_for_cpu(queue->dev->device,
> +			cmd->send_sge.addr, cmd->send_sge.length,
> +			DMA_TO_DEVICE);

Why the different indentation here?  Both one or two tab indents
look fine to me in this context, but don't mix them.

Except for that this looks fine:

Reviewed-by: Christoph Hellwig <hch at lst.de>