Re: [PATCH] dl2k: use explicit DMA_48BIT_MASK

[Jon Mason <jdmason@us.ibm.com>]

On Wed, May 10, 2006 at 08:57:18PM +0200, Francois Romieu wrote:
> Typo will be harder with this one.

While I agree that a #define is much better than the magic number, I
think this is bastardizing the intended use of DMA_*BIT_MASK.
DMA_*BIT_MASK is intended to be used in the DMA_API's checking of
DMA controller's addressable memory, where as this is masking off the
lower 48bits of a descriptor for its DMA address.  

I think a better solution (which I should've done when I pushed the
original patch) would be a driver specific #define.  

Thanks,
Jon

> 
> Signed-off-by: Francois Romieu <romieu@fr.zoreil.com>
> 
> ---
> 
>  drivers/net/dl2k.c          |   13 ++++++-------
>  include/linux/dma-mapping.h |    1 +
>  2 files changed, 7 insertions(+), 7 deletions(-)
> 
> 5019a27a2a4e259f29a7bd03e905764eedfa034c
> diff --git a/drivers/net/dl2k.c b/drivers/net/dl2k.c
> index ca73f07..18d67cf 100644
> --- a/drivers/net/dl2k.c
> +++ b/drivers/net/dl2k.c
> @@ -765,8 +765,7 @@ rio_free_tx (struct net_device *dev, int
>  			break;
>  		skb = np->tx_skbuff[entry];
>  		pci_unmap_single (np->pdev,
> -				  np->tx_ring[entry].fraginfo & 
> -						0xffffffffffffULL,
> +				  np->tx_ring[entry].fraginfo & DMA_48BIT_MASK,
>  				  skb->len, PCI_DMA_TODEVICE);
>  		if (irq)
>  			dev_kfree_skb_irq (skb);
> @@ -895,7 +894,7 @@ receive_packet (struct net_device *dev)
>  			if (pkt_len > copy_thresh) {
>  				pci_unmap_single (np->pdev,
>  						  desc->fraginfo & 
> -							0xffffffffffffULL,
> +							DMA_48BIT_MASK,
>  						  np->rx_buf_sz,
>  						  PCI_DMA_FROMDEVICE);
>  				skb_put (skb = np->rx_skbuff[entry], pkt_len);
> @@ -903,7 +902,7 @@ receive_packet (struct net_device *dev)
>  			} else if ((skb = dev_alloc_skb (pkt_len + 2)) != NULL) {
>  				pci_dma_sync_single_for_cpu(np->pdev,
>  				  			    desc->fraginfo & 
> -							      0xffffffffffffULL,
> +							      DMA_48BIT_MASK,
>  							    np->rx_buf_sz,
>  							    PCI_DMA_FROMDEVICE);
>  				skb->dev = dev;
> @@ -915,7 +914,7 @@ receive_packet (struct net_device *dev)
>  				skb_put (skb, pkt_len);
>  				pci_dma_sync_single_for_device(np->pdev,
>  				  			      desc->fraginfo & 
> -							      0xffffffffffffULL,
> +							      DMA_48BIT_MASK,
>  							       np->rx_buf_sz,
>  							       PCI_DMA_FROMDEVICE);
>  			}
> @@ -1803,7 +1802,7 @@ rio_close (struct net_device *dev)
>  		if (skb) {
>  			pci_unmap_single(np->pdev, 
>  					 np->rx_ring[i].fraginfo & 
> -						0xffffffffffffULL,
> +						DMA_48BIT_MASK,
>  					 skb->len, PCI_DMA_FROMDEVICE);
>  			dev_kfree_skb (skb);
>  			np->rx_skbuff[i] = NULL;
> @@ -1814,7 +1813,7 @@ rio_close (struct net_device *dev)
>  		if (skb) {
>  			pci_unmap_single(np->pdev, 
>  					 np->tx_ring[i].fraginfo & 
> -						0xffffffffffffULL,
> +						DMA_48BIT_MASK,
>  					 skb->len, PCI_DMA_TODEVICE);
>  			dev_kfree_skb (skb);
>  			np->tx_skbuff[i] = NULL;
> diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
> index ff61817..635690c 100644
> --- a/include/linux/dma-mapping.h
> +++ b/include/linux/dma-mapping.h
> @@ -14,6 +14,7 @@ enum dma_data_direction {
>  };
>  
>  #define DMA_64BIT_MASK	0xffffffffffffffffULL
> +#define DMA_48BIT_MASK	0x0000ffffffffffffULL
>  #define DMA_40BIT_MASK	0x000000ffffffffffULL
>  #define DMA_39BIT_MASK	0x0000007fffffffffULL
>  #define DMA_32BIT_MASK	0x00000000ffffffffULL
> -- 
> 1.3.1
> 
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