From: Alexander Duyck <alexander.h.duyck@xxxxxxxxx> Subject: arch/metag: add option to skip DMA sync as a part of map and unmap This change allows us to pass DMA_ATTR_SKIP_CPU_SYNC which allows us to avoid invoking cache line invalidation if the driver will just handle it via a sync_for_cpu or sync_for_device call. Link: http://lkml.kernel.org/r/20161110113503.76501.80809.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Alexander Duyck <alexander.h.duyck@xxxxxxxxx> Cc: James Hogan <james.hogan@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- arch/metag/kernel/dma.c | 16 +++++++++++++--- 1 file changed, 13 insertions(+), 3 deletions(-) diff -puN arch/metag/kernel/dma.c~arch-metag-add-option-to-skip-dma-sync-as-a-part-of-map-and-unmap arch/metag/kernel/dma.c --- a/arch/metag/kernel/dma.c~arch-metag-add-option-to-skip-dma-sync-as-a-part-of-map-and-unmap +++ a/arch/metag/kernel/dma.c @@ -484,8 +484,9 @@ static dma_addr_t metag_dma_map_page(str unsigned long offset, size_t size, enum dma_data_direction direction, unsigned long attrs) { - dma_sync_for_device((void *)(page_to_phys(page) + offset), size, - direction); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + dma_sync_for_device((void *)(page_to_phys(page) + offset), + size, direction); return page_to_phys(page) + offset; } @@ -493,7 +494,8 @@ static void metag_dma_unmap_page(struct size_t size, enum dma_data_direction direction, unsigned long attrs) { - dma_sync_for_cpu(phys_to_virt(dma_address), size, direction); + if (!(attrs & DMA_ATTR_SKIP_CPU_SYNC)) + dma_sync_for_cpu(phys_to_virt(dma_address), size, direction); } static int metag_dma_map_sg(struct device *dev, struct scatterlist *sglist, @@ -507,6 +509,10 @@ static int metag_dma_map_sg(struct devic BUG_ON(!sg_page(sg)); sg->dma_address = sg_phys(sg); + + if (attrs & DMA_ATTR_SKIP_CPU_SYNC) + continue; + dma_sync_for_device(sg_virt(sg), sg->length, direction); } @@ -525,6 +531,10 @@ static void metag_dma_unmap_sg(struct de BUG_ON(!sg_page(sg)); sg->dma_address = sg_phys(sg); + + if (attrs & DMA_ATTR_SKIP_CPU_SYNC) + continue; + dma_sync_for_cpu(sg_virt(sg), sg->length, direction); } } _ -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
