Re: [RFT][PATCH] generic device DMA implementation

[Alan Cox]

On Sat, 2002-12-28 at 03:39, Adam J. Richter wrote:
> 	I know Documentation/DMA-mapping.txt says that, and I
> understand that wmb() is necessary with consistent memory, but I
> wonder if rmb() really is, at least if you've declared the data
> structures in question as volatile to prevent reordering of reads by
> the compiler.

Compiler ordering != Processor to memory ordering != PCI device view
ordering

volatile may not be enough.

Alan