Hi Vinod, On Fri, Oct 9, 2015 at 9:42 PM, Vinod Koul <vinod.koul@xxxxxxxxx> wrote: > On Thu, Oct 08, 2015 at 02:36:57PM +0530, Rameshwar Prasad Sahu wrote: >> The DMA engine supports memory copy, RAID5 XOR, RAID6 PQ, and other >> computations. But the bandwidth of the entire DMA engine is shared >> among all channels. This patch re-configures operations availability >> such that one can achieve maximum performance for XOR and PQ >> computation by removing the memory offload operations. >> >> Signed-off-by: Rameshwar Prasad Sahu <rsahu@xxxxxxx> >> --- >> drivers/dma/xgene-dma.c | 1 - >> 1 file changed, 1 deletion(-) >> >> diff --git a/drivers/dma/xgene-dma.c b/drivers/dma/xgene-dma.c >> index 8d57b1b..cd38022 100644 >> --- a/drivers/dma/xgene-dma.c >> +++ b/drivers/dma/xgene-dma.c >> @@ -1707,7 +1707,6 @@ static void xgene_dma_set_caps(struct xgene_dma_chan *chan, >> dma_cap_zero(dma_dev->cap_mask); >> >> /* Set DMA device capability */ >> - dma_cap_set(DMA_MEMCPY, dma_dev->cap_mask); >> dma_cap_set(DMA_SG, dma_dev->cap_mask); > > This will not work. Still clients can invoke memcpy operation. You need to > remove the callback Got it, instead of removing the callback registration can we keep it inside the condition like.. if (dma_has_cap(DMA_MEMCPY, dma_dev->cap_mask)) dma_dev->device_prep_dma_memcpy = xgene_dma_prep_memcpy; > > -- > ~Vinod -- To unsubscribe from this list: send the line "unsubscribe dmaengine" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html