[openib-general] [PATCH v2 2/7] IB/ipath - Implement new verbs DMA mapping functions

[Ralph Campbell]

On Sun, 2006-12-03 at 10:42 +0200, Or Gerlitz wrote:
> Ralph Campbell wrote:
> > This patch implements the interposing DMA mapping functions to allow
> > support for IOMMUs and remove the dependence on phys_to_virt().
> 
> > --- /dev/null	Thu Jan 01 00:00:00 1970 +0000
> > +++ b/drivers/infiniband/hw/ipath/ipath_dma.c	Wed Nov 29 13:55:07 2006 -0800
> > +/**
> > + * ipath_dma_map_single - Map a kernel virtual address to DMA address
> > + * @device: The device for which the dma_addr is to be created
> > + * @cpu_addr: The kernel virtual address
> > + * @size: The size of the region in bytes
> > + * @direction: The direction of the DMA
> > + */
> > +static u64 ipath_dma_map_single(struct ib_device *dev,
> > +			        void *cpu_addr, size_t size,
> > +			        enum dma_data_direction direction)
> > +{
> > +	BUG_ON(!valid_dma_direction(direction));
> > +	return (u64) cpu_addr;
> > +}
> 
> if ipath_dma_map_single is a NO OP
> 
> > +/**
> > + * ipath_sync_single_for_cpu - Prepare DMA region to be accessed by CPU
> > + * @device: The device for which the DMA address was created
> > + * @addr: The DMA address
> > + * @size: The size of the region in bytes
> > + * @dir: The direction of the DMA
> > + */
> > +static void ipath_sync_single_for_cpu(struct ib_device *dev,
> > +				      u64 addr,
> > +				      size_t size,
> > +				      enum dma_data_direction dir)
> > +{
> > +	dma_sync_single_for_cpu(dev->dma_device, addr, size, dir);
> > +}
> 
> then why ipath_sync_single_for_cpu does something? am i just pointing on 
> a cleanup or there's something more deep here?
> 
> Or.

Good catch. There is nothing going on here.
The dma_sync_single_* should be NOPs.