[openib-general] IB/ipath - Implement new verbs DMA mapping functions

[James Lentini]

On Fri, 3 Nov 2006, Ralph Campbell wrote:

> On Fri, 2006-11-03 at 12:54 -0500, James Lentini wrote:
> > Ralph,
> > 
> > Could you add documentation to Documentation/infiniband/ explainin 
> > when a ULP needs to use the new verbs DMA mapping functions (what 
> > structures/function parameters must be specified using this API)? 
> 
> Good idea.  I will.

Thank you Ralph. This will be a big help to present and future ULP 
authors.

> > Did you consider creating a new type, ib_dma_addr_t, and using this 
> > type for the verb structure members/function parameters that require 
> > it?
> 
> I didn't really think about it since I was trying to make identical
> replacements for dma_map_single(), etc. which return dma_addr_t.
> That would pretty much force ib_dma_addr_t to be the same as
> dma_addr_t.

I suggested it as a way to self document the verbs API. It would make 
clear that for certain variables a call to the IB DMA mapping API was 
necessary. Of course, that benefit has to be weighed against the 
obfuscation created by an new typedef.