Re: [PATCH 08/28] MIPS: make dma_sync_*_for_cpu a little less overzealous

On Wed, Aug 19, 2020 at 08:55:35AM +0200, Christoph Hellwig wrote:

When transferring DMA ownership back to the CPU there should never be any writeback from the cache, as the buffer was owned by the device until now. Instead it should just be invalidated for the mapping directions where the device could have written data. Note that the changes rely on the fact that kmap_atomic is stubbed out for the !HIGHMEM case to simplify the code a bit.

Signed-off-by: Christoph Hellwig hch@lst.de

arch/mips/mm/dma-noncoherent.c | 44 +++++++++++++++++++++------------- 1 file changed, 28 insertions(+), 16 deletions(-)

Acked-by: Thomas Bogendoerfer tsbogend@alpha.franken.de