Hi Ben, On Mon, 2015-08-10 at 12:12 +0200, Ben Hutchings wrote: > 3.2.71-rc1 review patch. If anyone has any objections, please let me know. > > ------------------ > > From: Alexey Brodkin <alexey.brod...@synopsys.com> > > commit f1590670ce069eefeb93916391a67643e6ad1630 upstream. > > Current implementation of descriptor init procedure only takes > care about setting/clearing ownership flag in "des0"/"des1" > fields while it is perfectly possible to get unexpected bits > set because of the following factors: > > [1] On driver probe underlying memory allocated with > dma_alloc_coherent() might not be zeroed and so > it will be filled with garbage. > > [2] During driver operation some bits could be set by SD/MMC > controller (for example error flags etc). > > And unexpected and/or randomly set flags in "des0"/"des1" > fields may lead to unpredictable behavior of GMAC DMA block. > > This change addresses both items above with: > > [1] Use of dma_zalloc_coherent() instead of simple > dma_alloc_coherent() to make sure allocated memory is > zeroed. That shouldn't affect performance because > this allocation only happens once on driver probe. > > [2] Do explicit zeroing of both "des0" and "des1" fields > of all buffer descriptors during initialization of > DMA transfer. > > And while at it fixed identation of dma_free_coherent() > counterpart as well. > > Signed-off-by: Alexey Brodkin <abrod...@synopsys.com> > Cc: Giuseppe Cavallaro <peppe.cavall...@st.com> > Cc: arc-linux-...@synopsys.com > Cc: linux-kernel@vger.kernel.org > Cc: David Miller <da...@davemloft.net> > Signed-off-by: David S. Miller <da...@davemloft.net> > [bwh: Backported to 3.2: > - Adjust context, indentation > - Normal and extended descriptors are allocated in the same place here] > Signed-off-by: Ben Hutchings <b...@decadent.org.uk>
This patch looks good to me. Moreover that was exactly what I initially done on top of 3.18, see https://github.com/foss-for-synopsys-dwc-arc-processors/linux/commit/f2105b2ba9b3444568b32caca1ab253b88058fc2 So feel free to add Acked-by and/or Tested-by: Alexey Brodkin <abrod...@synopsys.com> -Alexey-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/