On Tue, Jan 10, 2023 at 04:03:06PM +0100, Arnd Bergmann wrote: > On Tue, Jan 10, 2023, at 08:01, Christoph Hellwig wrote: > > On Mon, Jan 09, 2023 at 01:59:12PM +0100, Arnd Bergmann wrote: > >> I had another look at the arm64 side, which (like the zicbom > >> variant) uses 'clean' on dma_sync_single_for_device(DMA_FROM_DEVICE), > >> as that has changed not that long ago, see > >> > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=c50f11c6196f45c92ca48b16a5071615d4ae0572 > > > > which IIRC has been reverted recently. > > To clarify: I was looking at arch_sync_dma_for_device(), which > changed from 'invalidate' to 'clean' last June in commit > c50f11c6196f ("arm64: mm: Don't invalidate FROM_DEVICE buffers > at start of DMA transfer"). I don't see a revert for that. > > The one that was reverted recently is arch_dma_prep_coherent, which > was changed and reverted in > > c44094eee32 Aug 23 2022 flush->clean > b7d9aae4048 Dec 6 2022 clean->flush > > I'm primarily interested in the streaming mappings (arch_sync_*) > at the moment. Just as an FYI, but we plan to revert the revert (i.e. go back to 'clean') here once Qualcomm's modem firmware loader has been updated: https://lore.kernel.org/r/20230109034843.23759-1-quic_sibis@xxxxxxxxxxx Will
