lkml.org 
[lkml]   [2020]   [Jul]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH v4 5/7] powerpc/iommu: Move iommu_table cleaning routine to iommu_table_clean
From
Date
On Tue, 2020-07-21 at 19:52 -0500, Brian King wrote:
> >
> > As of today, there seems to be nothing like that happening in the
> > driver I am testing.
> > I spoke to Brian King on slack, and he mentioned that at the point DDW
> > is created there should be no allocations in place.
>
> I think there are a couple of scenarios here. One is where there is a DMA
> allocation prior to a call to set the DMA mask. Second scenario is if the
> driver makes multiple calls to set the DMA mask. I would argue that a properly
> written driver should tell the IOMMU subsystem what DMA mask it supports prior
> to allocating DMA memroy. Documentation/core-api/dma-api-howto.rst should
> describe what is legal and what is not.
>
> It might be reasonable to declare its not allowed to allocate DMA memory
> and then later change the DMA mask and clearly call this out in the documentation
> if its not already.
>
> -Brian

Thank you for the feedback Brian!

That makes sense to me. I will try to have this in mind for the next
patchset.

Best regards,

\
 
 \ /
  Last update: 2020-07-23 01:46    [W:0.060 / U:0.696 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site