From: Jose Abreu <[email protected]> Date: Tue, 30 Jul 2019 15:57:16 +0200
> With recent changes that introduced support for Page Pool in stmmac, Jon > reported that NFS boot was no longer working on an ARM64 based platform > that had the IP behind an IOMMU. > > As Page Pool API does not guarantee DMA syncing because of the use of > DMA_ATTR_SKIP_CPU_SYNC flag, we have to explicit sync the whole buffer upon > re-allocation because we are always re-using same pages. > > In fact, ARM64 code invalidates the DMA area upon two situations [1]: > - sync_single_for_cpu(): Invalidates if direction != DMA_TO_DEVICE > - sync_single_for_device(): Invalidates if direction == DMA_FROM_DEVICE > > So, as we must invalidate both the current RX buffer and the newly allocated > buffer we propose this fix. > > [1] arch/arm64/mm/cache.S > > Reported-by: Jon Hunter <[email protected]> > Tested-by: Jon Hunter <[email protected]> > Fixes: 2af6106ae949 ("net: stmmac: Introducing support for Page Pool") > Signed-off-by: Jose Abreu <[email protected]> Applied.
