Messages in this thread | | | Date | Tue, 30 Jul 2019 10:26:38 -0700 (PDT) | Subject | Re: [PATCH net] net: stmmac: Sync RX Buffer upon allocation | From | David Miller <> |
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From: Jose Abreu <Jose.Abreu@synopsys.com> 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 <jonathanh@nvidia.com> > Tested-by: Jon Hunter <jonathanh@nvidia.com> > Fixes: 2af6106ae949 ("net: stmmac: Introducing support for Page Pool") > Signed-off-by: Jose Abreu <joabreu@synopsys.com>
Applied.
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