Missing cache flush.

[David S. Miller]

Jeff Garzik writes:
 > David Woodhouse wrote:
 > > I was pointed at Documentation/DMA-mapping.txt but that doesn't seem very
 > > helpful - it's very PCI-specific, and a quick perusal of pci_dma_sync() on
 > > i386 shows that it doesn't do what's required anyway.
 > 
 > What should it do on i386?  mb()?

The x86 doesn't have dumb caches, therefore it really doesn't need to
flush anything.  Maybe a mb(), but that is it.

Later,
David S. Miller
davem at redhat.com