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Subject: Re: [PATCH rdma-next v1] RDMA: Explicitly pass in the dma_device to
 ib_register_device
Message-ID: <20201005135110.GA12620@infradead.org>
References: <20201005110050.1703618-1-leon@kernel.org>
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> 
> -static void setup_dma_device(struct ib_device *device)
> +static void setup_dma_device(struct ib_device *device,
> +			     struct device *dma_device)
>  {
> +	if (!dma_device) {
>  		/*
> +		 * If the caller does not provide a DMA capable device then the
> +		 * IB device will be used. In this case the caller should fully
> +		 * setup the ibdev for DMA. This usually means using
> +		 * dma_virt_ops.
>  		 */
> +#ifdef CONFIG_DMA_OPS
> +		if (WARN_ON(!device->dev.dma_ops))
> +			return;
> +#endif

Per the discussion last round I think this needs to warn if the ops
is not dma_virt_ops, or even better force dma_virt_ops here.

Something like:

	if (!dma_device) {
		if (WARN_ON_ONCE(!IS_ENABLED(CONFIG_DMA_VIRT_OPS)))
			return -EINVAL;
		device->dev.dma_ops = &dma_virt_ops;

> +		if (WARN_ON(!device->dev.dma_parms))
> +			return;

I think you either want this check to operate on the dma_device and be
called for both branches, or removed entirely now that the callers setup
the dma params.