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H A D | dma.c | 4c612add Tue Jul 24 09:13:02 CDT 2018 Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> ARC: dma [non IOC]: fix arc_dma_sync_single_for_(device|cpu)
ARC backend for dma_sync_single_for_(device|cpu) was broken as it was not honoring the @dir argument and simply forcing it based on the call: - arc_dma_sync_single_for_device(dir) assumed DMA_TO_DEVICE (cache wback) - arc_dma_sync_single_for_cpu(dir) assumed DMA_FROM_DEVICE (cache inv)
This is not true given the DMA API programming model and has been discussed here [1] in some detail.
Interestingly while the deficiency has been there forever, it only started showing up after 4.17 dma common ops rework, commit a8eb92d02dd7 ("arc: fix arc_dma_{map,unmap}_page") which wired up these calls under the more commonly used dma_map_page API triggering the issue.
[1]: https://lkml.org/lkml/2018/5/18/979 Fixes: commit a8eb92d02dd7 ("arc: fix arc_dma_{map,unmap}_page") Cc: stable@kernel.org # v4.17+ Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> [vgupta: reworked changelog] 4c612add Tue Jul 24 09:13:02 CDT 2018 Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> ARC: dma [non IOC]: fix arc_dma_sync_single_for_(device|cpu) ARC backend for dma_sync_single_for_(device|cpu) was broken as it was not honoring the @dir argument and simply forcing it based on the call: - arc_dma_sync_single_for_device(dir) assumed DMA_TO_DEVICE (cache wback) - arc_dma_sync_single_for_cpu(dir) assumed DMA_FROM_DEVICE (cache inv) This is not true given the DMA API programming model and has been discussed here [1] in some detail. Interestingly while the deficiency has been there forever, it only started showing up after 4.17 dma common ops rework, commit a8eb92d02dd7 ("arc: fix arc_dma_{map,unmap}_page") which wired up these calls under the more commonly used dma_map_page API triggering the issue. [1]: https://lkml.org/lkml/2018/5/18/979 Fixes: commit a8eb92d02dd7 ("arc: fix arc_dma_{map,unmap}_page") Cc: stable@kernel.org # v4.17+ Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> [vgupta: reworked changelog]
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