Re: [Qemu-devel] [RFC PATCH 01/13] Generic DMA memory access interface

Richard Henderson
2011-06-01T15:16:49Z

On 06/01/2011 07:29 AM, Avi Kivity wrote:
> On 06/01/2011 05:01 PM, Richard Henderson wrote:
>> > + err = dev->mmu->translate(dev, addr,&paddr,&plen, is_write);
>>
>> I see you didn't take my suggestion for using an opaque callback pointer.
>> Really and truly, I won't be able to use this as-is for Alpha.
>>
>
> Rather than opaques, please pass the DMA engine itself and use container_of().

The dma engine object is currently sitting in the PCIBus structure.
Which is private, and can't be extended by a host bridge implementation.

The entire code could be re-arranged, true, but please suggest something
reasonable.

> We should be removing opaques, not adding them.

See my followup elsewhere. Opaques *can* be cleaner than upcasting,
particularly if there are too many hoops through which to jump.

r~