From fdaf9c4b22247a6cc6cda9459be3e52764c14d95 Mon Sep 17 00:00:00 2001 From: Lars-Peter Clausen Date: Wed, 25 Apr 2012 20:50:52 +0200 Subject: dmaengine: Use dma_sg_len(sg) instead of sg->length sg->length may or may not contain the length of the dma region to transfer, depending on the architecture - dma_sg_len(sg) always will though. For the architectures which use the drivers modified by this patch it probably is the case that sg->length contains the dma transfer length. But to be consistent and future proof change them to use dma_sg_len. To quote Russel King: sg->length is meaningless to something performing DMA. In cases where sg_dma_len(sg) and sg->length are the same storage, then there's no problem. But scatterlists _can_ (and one some architectures) do split them - especially when you have an IOMMU which can allow you to combine a scatterlist into fewer entries. So, anything using sg->length for the size of a scatterlist's DMA transfer _after_ a call to dma_map_sg() is almost certainly buggy. The patch has been generated using the following coccinelle patch: @@ struct scatterlist *sg; expression X; @@ -sg[X].length +sg_dma_len(&sg[X]) @@ struct scatterlist *sg; @@ -sg->length +sg_dma_len(sg) Signed-off-by: Lars-Peter Clausen Acked-by: Linus Walleij Signed-off-by: Vinod Koul --- drivers/dma/coh901318.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/dma/coh901318.c') diff --git a/drivers/dma/coh901318.c b/drivers/dma/coh901318.c index dc89455f5550..c0b650c70bbd 100644 --- a/drivers/dma/coh901318.c +++ b/drivers/dma/coh901318.c @@ -1040,7 +1040,7 @@ coh901318_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, if (!sgl) goto out; - if (sgl->length == 0) + if (sg_dma_len(sgl) == 0) goto out; spin_lock_irqsave(&cohc->lock, flg); -- cgit v1.2.3-59-g8ed1b