Re: [RFC PATCH 1/2] swiotlb: Split up single swiotlb lock

[Robin Murphy]

On 2022-04-28 15:45, Christoph Hellwig wrote:
> On Thu, Apr 28, 2022 at 03:44:36PM +0100, Robin Murphy wrote:
> > Rather than introduce this extra level of allocator complexity, how about
> > just dividing up the initial SWIOTLB allocation into multiple io_tlb_mem
> > instances?
>
> Yeah.  We're almost done removing all knowledge of swiotlb from drivers,
> so the very last thing I want is an interface that allows a driver to
> allocate a per-device buffer.

FWIW I'd already started thinking about having a distinct io_tlb_mem for 
non-coherent devices where vaddr is made non-cacheable to avoid the 
hassle of keeping the arch_dma_sync_* calls lined up, so I'm certainly 
in favour of bringing in a bit more flexibility at this level :)

Robin.