From c456797681db814f4f5b36909e8e94047bf53d9c Mon Sep 17 00:00:00 2001 From: Nicolas Ferre Date: Tue, 11 Sep 2012 17:21:45 +0200 Subject: [PATCH] dmaengine: at_hdmac: check that each sg data length is non-null Avoid the construction of a malformed DMA request sent to the DMA controller. Log message is for debug only because this condition is unlikely to append and may only trigger at driver development time. Signed-off-by: Nicolas Ferre Cc: Stable [2.6.31+] Signed-off-by: Vinod Koul --- drivers/dma/at_hdmac.c | 11 +++++++++++ 1 file changed, 11 insertions(+) diff --git a/drivers/dma/at_hdmac.c b/drivers/dma/at_hdmac.c index 6c09e186e960..7ab6e26664a7 100644 --- a/drivers/dma/at_hdmac.c +++ b/drivers/dma/at_hdmac.c @@ -689,6 +689,11 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, mem = sg_dma_address(sg); len = sg_dma_len(sg); + if (unlikely(!len)) { + dev_dbg(chan2dev(chan), + "prep_slave_sg: sg(%d) data length is zero\n", i); + goto err; + } mem_width = 2; if (unlikely(mem & 3 || len & 3)) mem_width = 0; @@ -724,6 +729,11 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, mem = sg_dma_address(sg); len = sg_dma_len(sg); + if (unlikely(!len)) { + dev_dbg(chan2dev(chan), + "prep_slave_sg: sg(%d) data length is zero\n", i); + goto err; + } mem_width = 2; if (unlikely(mem & 3 || len & 3)) mem_width = 0; @@ -757,6 +767,7 @@ atc_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl, err_desc_get: dev_err(chan2dev(chan), "not enough descriptors available\n"); +err: atc_desc_put(atchan, first); return NULL; }