[openib-general] Re: [PATCH 5 of 13] ipath - use proper address translation routine

[Roland Dreier]

    Arjan> do you really NEED the vaddr?  (most of the time linux
    Arjan> drivers don't need it, while other OSes do) If you really
    Arjan> need it you should grab it at dma_map time ...  (and
    Arjan> realize that it's not kernel addressable per se ;)

Yes, they need some kind of vaddr.

It's kind of a layering problem.  The IB stack assumes that IB devices
have a DMA engine that deals with bus addresses.  But the ipath driver
has to simulate this by using a memcpy on the CPU to move data to the
PCI device.

I really don't know what the right solution is.  Maybe having some way
to override the dma mapping operations so that the ipath driver can
keep the info it needs?

 - R.