Re: SCSI breakage on non-cache coherent architectures

Matthew Wilcox
2007-11-19T12:32:53Z

On Mon, Nov 19, 2007 at 04:35:23PM +1100, Benjamin Herrenschmidt wrote:
> The other one I'm hitting now is that the SCSI layer nowadays embeds the

'nowadays'? It has always been so.

> sense_buffer inside the scsi_cmnd structure without any kind of
> alignment whatsoever. I've been hitting irregulary is a crash on SCSI command
> completion that seems to be related to corruption of the "request"
> pointer in struct scsi_cmnd and I think it might be the cause.
> I'm now trying to setup a proper repro-case.

What other drivers do is DMA to their own allocation and then memcpy to
the sense buffer.

There is a movement to allocate the sense data as its own sg list, but
I don't think that patch has even been posted yet.

--
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