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

Alan Cox (
30 Dec 2002 00:45:54 +0000

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

volatile may not be enough.


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