Messages in this thread | | | Date | Fri, 1 Oct 2021 06:19:59 +0200 | From | Christoph Hellwig <> | Subject | Re: DPAA2 triggers, [PATCH] dma debug: report -EEXIST errors in add_dma_entry |
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On Tue, Sep 14, 2021 at 03:45:06PM +0000, Ioana Ciornei wrote: > [ 245.927020] fsl_dpaa2_eth dpni.3: scather-gather idx 0 P=20a7320000 N=20a7320 D=20a7320000 L=30 DMA_BIDIRECTIONAL dma map error check not applicable· > [ 245.927048] fsl_dpaa2_eth dpni.3: scather-gather idx 1 P=20a7320030 N=20a7320 D=20a7320030 L=5a8 DMA_BIDIRECTIONAL dma map error check not applicable > [ 245.927062] DMA-API: cacheline tracking EEXIST, overlapping mappings aren't supported > > The first line is the dump of the dma_debug_entry which is already present > in the radix tree and the second one is the entry which just triggered > the EEXIST. > > As we can see, they are not actually overlapping, at least from my > understanding. The first one starts at 0x20a7320000 with a size 0x30 > and the second one at 0x20a7320030.
They overlap the cache lines. Which means if you use this driver on a system that is not dma coherent you will corrupt data.
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