RE: WARNING in dma_map_page_attrs

[Parav Pandit]

> From: hch@xxxxxx <hch@xxxxxx>
> Sent: Tuesday, October 27, 2020 1:41 PM
> 
> On Mon, Oct 26, 2020 at 05:23:48AM +0000, Parav Pandit wrote:
> > Hi Christoph,
> >
> > > From: Jakub Kicinski <kuba@xxxxxxxxxx>
> > > Sent: Saturday, October 24, 2020 11:45 PM
> > >
> > > CC: rdma, looks like rdma from the stack trace
> > >
> > > On Fri, 23 Oct 2020 20:07:17 -0700 syzbot wrote:
> > > > syzbot has found a reproducer for the following issue on:
> > > >
> > > > HEAD commit:    3cb12d27 Merge tag 'net-5.10-rc1' of
> git://git.kernel.org/..
> >
> > In [1] you mentioned that dma_mask should not be set for dma_virt_ops.
> > So patch [2] removed it.
> >
> > But check to validate the dma mask for all dma_ops was added in [3].
> >
> > What is the right way? Did I misunderstood your comment about
> dma_mask in [1]?
> 
> No, I did not say we don't need the mask.  I said copying over the various
> dma-related fields from the parent is bogus.
> 
> I think rxe (and ther other drivers/infiniband/sw drivers) need a simple
> dma_coerce_mask_and_coherent and nothing else.

I see. Does below fix make sense?
Is DMA_MASK_NONE correct?