Re: dma api errors with swiotlb

From: Christoph Hellwig
Date: Wed Sep 04 2019 - 09:16:40 EST

On Wed, Sep 04, 2019 at 03:02:14PM +0200, Thomas Hellström (VMware) wrote:
> It looks like it does that, although when we send it, the SWIOTLB error has
> already occured and been printed out, and then the sequence starts again.

Well, the only way to really find out is to try. We also have a
backoff algorithm in the SCSI midlayer, so it should not be much of
an inpact. If you care about the warnings they can be disabled using
DMA_ATTR_NO_WARN. I have to admit that I'm not even sure the warnings
are all that useful, but that's something you need to take up with
the swiotlb maintainer.